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The Concept of Genotypic IQ is False and Socially Destructive

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The concept of “genotypic IQ” (GIQ) refers to a theoretical genetic potential of IQ. Basically, GIQ is one’s IQ without any corresponding environmental insults, and of course it is due the interaction of many genes each with small effect (which is the justification for GWAS). This, though, is like the concept of true score. “A true score is the hypothetical average of a thousand parallel testings of someone’s intellectual abilities.” Nevertheless, this concept of GIQ is used by hereditarians to proclaim that “genotypic intelligence is deteriorating” (Lynn, 1998) and this is due to “dysgenic fertility“, which is “a negative correlation between intelligence and the number of children” (Lynn and Harvey, 2008: 112), while “genotypic IQ” is “Genotypic intelligence is the genetic component of intelligence and it is this that has been declining” (Lynn and Harvey, 2008: 113) or is the IQ they have if they have access to optimal environments. I will argue in this article why the concept of GIQ is nonsense.

What is GIQ?

So GIQ is the so-called genetic component of intelligence. This, of course, is based on the assumption that genes are causative for IQ. This is based on the assumption that, however weakly, heritability can tell us anything about genetic causation (it can’t).

Lynn (2015) talks about the GIQs of Africans, pygmies, and aborigines. He also claims that the IQ of African Americans is “solely genetically determined“, since it hasn’t changed in some 80 years. This claim, though, is false (Dickens and Flynn, 2006). Nevertheless, the claim of GIQ arises due to the assumption—which hasn’t been tested, nor can it—that IQ and other psychological traits are caused/influenced by genes. I have argued at length that this claim is false.

It seems that the only people discussing this concept are the usual suspects (Lynn, 2015, 2018; Woodley of Menie, 2015; Madison, Woodley of Menie, and Sanger, 2016; Kirkegaard, Lasker, and Kura, 2019; Piffer, 2023). The decline in so-called genotypic IQ is used as a cudgel to try to argue that “dysgenic effects” of low IQ women having more children is leading to this effect. Weiss (2021: 35) puts it like this:

If women with a low IQ give birth to their children earlier than women with a high IQ, the mean genotypic IQ of the population will also decrease (Comings 1996), even if the number of children in both population strata should be the same. If the number of children across the IQ distribution is not equal (Blake 1989), the next generation will have a different IQ distribution.

Quite obviously, the hereditarian claim of GIQ is that some individuals—and of course groups—are genetically more intelligent than others. Nevertheless, a women “with a low IQ” doesn’t have a low IQ due to genetics; if we think about the nature of IQ and the types of items on the test, we then come to the conclusion that these tests aren’t a test of one’s genetic potential for learning ability (as many have claimed), but it’s merely what one has been exposed to and learned.

We have also used this concept of GIQ to attempt to show that these genes we have found to be associated with IQ have been in decline. Cretan (2016)—in a paper titled “Was Cro-Magnon the Most Intelligent Modern Human?“—tries to argue that GIQ has decreased since Neolithic times, and that the decrease in height and brain size since then is expected, since they are moderately correlated. However, the so-called brain size increase seems to be an artifact (Deacon, 1990a, 1990b). Cretan (2016: 158-159) writes:

Genotypic” intelligence changes across millennia because the genetic variants, or alleles, that enable people to develop higher intelligence change their frequencies due to mutation and selection. Evolution by mutation and selection implies that at a certain selection pressure favoring higher intelligence, the genotypic intelligence of a population remains constant. At selection pressures below this break-even point, intelligence will decrease; at higher selection pressure, intelligence will increase. In the complete absence of selection, genotypic IQ will not remain constant.

As we can see, this concept of GIQ and the so-called decrease in it has been sounding hereditarian alarm bells for decades. People like Lynn and Jensen push eugenic ideals on the basis of low intelligence people having more children, pushing for a negative eugenic practice to prevent people with low IQ from having children. Jensen, in his infamous 1969 paper, was pretty much explicit with these aims, and then in 1970 he stated that heritability can tell use one’s genetic standing when it comes to intelligence. Richard Lynn, in his review of Cattell’s Beyondism, called for “realistically phasing out” certain populations, but that it wasn’t eugenic:

“Is there a danger that current welfare policies, unaided by eugenic foresight, could lead to the genetic enslavement of a substantial segment of our population?” – Jensen, 1969: 95How Much Can We Boost IQ and Scholastic Achievement?

“What the evidence on heritability tells us is that we can, in fact, estimate a person’s genetic standing on intelligence from his score on an IQ test.” – Jensen, 1970, Can We and Should We Study Race Difference?

“What is called for here is not genocide, the killing off of the populations of incompetent cultures. But we do need to think realistically in terms of “phasing out” of such peoples.” [Lynn]

This is an example of negative eugenics—preventing those who were thought to have undesirable traits from breeding. William Shockley—who was Arthur Jensen’s inspiration—talked about paying people to undergo sterilization. This was called the voluntary sterilization bonus plan:

Shockley is proposing varying bonuses to anyone with an IQ under 100 who agrees to be sterilized upon reaching child-bearing age. He would pay volunteers $1,000 for every IQ point below 100, with “$30,000 put into a trust fund for a 70-IQ moron, potentially capable of producing 20 children.”

Under the plan, bonuses would also go to potential parents based on the “best scientific estimates” of their having such “genetically carried disabilities as hemophilia, sickle cell anemia, epilepsy, Huntington’s chorea and so on,” with taxpayers getting no money to participate.

This is another example of negative eugenics, but there is of course also positive eugenics—encouraging those with desired traits to have more children. In his article Bright New World, Moen (2016) discusses this kind of positive eugenics, while endorsing the claim of GIQ. Moen proposed that women should be paid modest sums of cash to have children with high IQ sperm donors, not their husbands:

Here I would like to suggest an alternative way to raise global IQ: giving prospective mothers modest monetary incentives to have children that genetically belong not to their husbands (or to ordinary sperm donors) but to high-IQ sperm donors.

These are the kinds of views and ultimate consequences that derive from such thinking that there is GIQ. Since we know that IQ can’t be genetic, there can be no GIQ. If there can be no GIQ, then such proposals like these negative and positive eugenic ideas that I just cited would merely just be getting rid of people that are not socially desireable—mainly the lower class, along with blacks since they are more likely to be lower class and have lower IQs (due to knowledge exposure and differential access to cultural and psychological tools). This concept of GIQ has, since the advent of IQ tests in America, been used to sterilize people in the name of eugenics. The moral wrongness of eugenics is why we should reject this concept, nevermind the irreducibility arguments. Eugenic policies discriminate against people based on arbitrary criteria and violate their reproductive rights.

Arguments against GIQ

Now that I have described what GIQ is and how it has been used in the past in the name of eugenics, here are a few arguments to invalidate the concept.

P1: If IQ is solely determined by one’s genetic makeup, then IQ scores should remain stable through one’s lifetime.
P2: IQ scores do not remain relatively stable through one’s lifetime.
C: Thus, IQ is not solely determined by one’s genetic makeup.

P1: If IQ is solely determined by genetics, then individuals with high IQ parents should also have high IQ scores.
P2: If individuals with high IQ parents also have high IQ scores, then adoption should not affect their IQ scores.
P3: Adoption does affect the IQ scores of individuals with high IQ parents.
C: Thus intelligence is not solely determined by genetics.

This argument contradicts the main claim of GIQ, since adoption has been shown to raise IQ (see Capron and Duyme, 1989; Locurto, 1990; Flynn, 1993; Duyme, Dumaret, and Tomkiwicz, 1999; Kendler et al, 2015; see Nisbett et al, 2012 for review).

P1: If the concept of GIQ were true, then one’s IQ would be determined by their genetics.
P2: Genes don’t determine traits, nevermind psychological ones.
C: Therefore, the concept of GIQ is false.

P1: If psychological traits are reducible to genetics, then environment plays no role in shaping IQ and the concept of GIQ is true.
P2: The environment plays a significant role in shaping IQ, as adoption studies show.
C: Therefore psychological traits are not reducible to genetics and the concept of GIQ is false.


P1: If psychological traits are irreducible, then the concept of GIQ is false.
P2: Psychological traits are irreducible.
C: Therefore, the concept of GIQ is false.

Both of these argument draw on the irreducibility of the mental arguments I’ve been making for years. If the mental is irreducible to the physical, then the concept of GIQ can’t possibly be true.

P1: Either the concept of GIQ is true and implies that IQ is determined by genes alone, or the concept of GIQ is false and other factors other than genes contribute to IQ.
P2: If the concept of GIQ is true and implies genetic determinism, then it ignores the significant impact that environmental factors have on IQ and may perpetuate discrimination against those with low IQ.
P3: If the concept of GIQ is false and other factors other than genes contribute to IQ, then efforts should be focused on addressing these other factors rather than assuming that genes are the sole determinant of IQ.
C: Thus, either the concept of GIQ perpetuates discriminatory attitudes if true, or it distracts from addressing the true determinants of IQ if false.

P1 is logically true, while P2 and P3 are supported by scientific evidence, so the argument is plausible.

The concept of GIQ assumes that IQ is largely determined by genetics, and that individuals have different genetic potentials for IQ. There is no clear, consistent definition of intelligence. The factors that contribute to IQ are complex and multifaceted. So any attempt at reducing one’s IQ to their genes or to make predictions about one’s IQ from their genes along is inherently flawed and oversimplified. Thus, the concept of GIQ is not a valid or useful way of understanding intelligence, and so attempts to use it to make policy or social decisions would be misguided. So this argument challenges the concept of GIQ, since there is no accepted definition of intelligence. That’s more than enough to discount the concept entirely.


I have described the concept of GIQ that many hereditarians in the literature have espoused. It is described as one’s genetic potential for IQ sans environmental insults. The usual suspects are arguing for a GIQ. However as can be seen historically, this concept had led to destructive consequences for groups of people and individuals who are deemed less intelligent. It has been argued that those who have low IQs should not have children and that either people should be paid to not have children and get sterilized or to influence high IQ mother’s to have children not with their husbands but high IQ sperm donors. Eugenics is morally wrong so we should not do that, nevermind the fact that genes don’t work how hereditarians need them to. Nevertheless, I have given a few arguments that the concept of GIQ is misleading at worst and socially destructive at best. This is yet another reason why we should ban IQ tests.

Thus, the concept of GIQ is merely false eugenic nonsense.


Prenatal Testing to Screen for Diseases is Eugenic: The Eugenic Nature of Prenatal Testing

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The concept of eugenics has a long history. Back in 2018, I surveyed the history of eugenics throughout antiquity to the modern day in different countries. It seems that the Greeks were the first to employ the concept. Both Aristotle and Plato wanted the state go be in charge of the birthing process, which is a classical definition of eugenics. People have even been sterilized in recent history, as recent as 20 years ago in California.

After the defeat of the Nazis in WW2, though, such eugenic ideas have never left. They have just changed form. We are in the new millennium and so we have new technologies that may allow us to screen for certain disseases and terminate then early on in the process. In this article, I will argue that using such technologies to prevent the births of such people are eugenic. I will give a few arguments and then I will connect them.

The “new eugenics”, same as the old eugenics

“New eugenics” refers to the use of advanced genetic technologies to improve or enhance genetic traits of humans or to selectively breed humans with desired traits while discouraging or preventing the reproduction of those with undesired traits. This tracks with “classical eugenics”, which was a socio-political movement in the late 18th to early 19th century which aimed at improving the human gene pool through encouraging the selective breeding of those with desirable traits while discouraging or preventing the reproduction of those with undesired traits, through coercion such as forced sterilization and euthanasia of individuals who have undesired traits like mental illness, physical disabilities or criminal tendencies. So as can be seen, both the old and new eugenics both involve the same basic practice of selective breeding of humans based on their genetic traits. Thus, both forms of eugenics are reductive in nature.

Both kinds of eugenics are morally wrong. By “morally wrong” I mean that it is not in accordance with accepted ethical principles and values. So calling eugenics “morally wrong” indicates that it is ethically unacceptable to most people, since it goes against the fundamental principles of human dignity, social justice, and human autonomy.

It’s a violation of human dignity and autonomy (Zaluski, 2010) since it makes decisions about a person’s life and reproductive choices based on their genetic makeup rather than their own desires and preferences. It can also stigmatize certain groups while perpetuating existing socio-economic inequalities by reinforcing the dominance of certain groups while marginalizing others. So it can result in further stigmatization and discrimination of certain groups based on their perceived genetic traits which would then lead to a loss of social cohesion along with a decrease in societal well-being. Selective breeding can also lead to a loss of genetic diversity in humans, which could then have further negative effects on our species’ ability for long-term survival and adaptation. And there are concerns involving the new eugenics like gene editing and PGD while there of course could be unintended, unforseen consequences and side effects while new forms of inequality and discrimination could emerge.

So here is the argument that eugenics is morally wrong.

P1: If a practice involves the selective breeding of humans based on their genetic traits, it is permissible only if it respects the autonomy and dignity of all individuals involved.
P2: Eugenics involves the selective breeding of humans based on their genetic traits.
P3: Eugenics does not respect the autonomy and dignity of all individuals involved.
C: Therefore, eugenics is morally wrong.

Premise 1 can be defended by the idea that every human has inherent value and deserves to be treated with respect and dignity regardless of their genetic makeup. Premise 2 is an accepted feature of both the old and the new eugenics. Premise 3 can be supported on the basis that eugenic practices involve the imposition of genetic traits on individuals without their consent, and it could also lead to the stigmatization and marginalization of those with so-called undesired genetic traits which would violate the fundamental ethical principles of human dignity and autonomy. So from (1), (2), and (3), and Conclusion follows that eugenics is morally wrong since it involves the selective breeding of humans based on their genetic traits while failing to respect the autonomy and dignity of all individuals involved.

Eugenics won’t work because genetic reductionism is false

Genetic reductionism is the view that genes are the primary determinants of human traits. It is the view that complex traits and behaviors can be reduced to and explained by genetic and biological factors while non-genetic and environmental factors are insignificant determinants. In the eugenic view—and in the view of most people—traits are primarily genetically caused, and by using genetic engineering and similar new-age tools, we can then guide out evolution and prune out both genes that lead to undesired traits and, in effect, people too. However, genetic reductionism is false. It is false because there is no privileged causal role in development of any of the developmental resources, genes included (Noble, 2012). So it then follows that eugenics can’t work, since eugenics is genetically reductionistic, and genetic reductionism is false. So the practice of eugenics is unlikely to work and may lead to unintended consequences. Here’s the formalized argument:

P1: If eugenics is based on the assumption that genetic traits are the primary determinants of human traits, then eugenics is genetically reductionistic.
P2: Eugenics is based on the assumption that genetic traits are the primary determinants of human traits.
P3: Genetic reductionism is false.
C: Therefore, eugenics cannot work.

Just like eugenics is genetically reductionistic, so is hereditarianism and that’s also why hereditarianism cannot work. And many hereditarians, like Lynn, Jensen, Shockley, and Cattell held eugenic views (just like Murray and Herrnstein, but they were much more careful with their language, though the underlying ideas are the same) and they are, of course, genetic reductionists. It is, after all, with the advent of IQ tests that eugenics had it’s start in America, and that’s one of the reasons why IQ tests should be banned, since they can and have led to morally wrong policies.

New genetic technologies are eugenic

I have given a pro- and anti-argument for the use of preimplantation genetic diagnosis (PGD) back in 2018. PGD is a procedure which allows parents to screen embryos for genetic abnormalities before implatiation during IVF. This process is often based on the desire to avoid certain traits or to select for certain desirable traits. As I argued above, the new boss is the same as the old boss—the new eugenics has similar end-goals as the old eugenics. PGD doesn’t involve coercion or forced sterilization like the old eugenics, yet it still has intended goals which are similar to the old eugenics by creating “genetically better” people by selecting for certain genes while avoiding others, under the assumption of genetic causation of socially-desired and undesired traits. This can then lead to the homogenization of our species, since people with certain traits could become more common while others without them become rarer. This can also lead to the discrimination of those who do not have the desired traits. Thus, PGD is a form of new eugenics and it is eugenic because it has the same end-goals as the old eugenics.

P1: If PGD isn’t a form of new eugenics, then it does not involve a selective breeding process based on genetic traits that can lead to a homogenization of the human population and discrimination against those who do not possess the desired traits.
P2: PGD does involve a selective breeding process based on genetic traits that can lead to a homogenization of the human population and discrimination against those who do not possess the desired traits.
C: Therefore, PGD is a form of new eugenics.

I have already provided an argument which establishes that eugenics is morally wrong. Now here are a few more arguments which establish PGD as a eugenic practice.

P1: If prenatal testing is used to screen for diseases to abort babies, then it is selectively terminating those with undesirable genetic traits.
P2: If selective termination of those with undesirable genetic traits is practice then it is a eugenic practice.
C: Thus, if prenatal testing is used to screen for diseases to abort babies, then it is a eugenic practice.

P1: If prenatal testing is not a eugenic practice, then it is not selectively terminating those with undesirable genetic traits.
P2: Prenatal testing is selectively terminating those with undesirable genetic traits.
C: Therefore prenatal testing is a eugenic practice.

P1: If a practice is eugenic, then it involves the selective breeding or termination of individuals with undesirable genetic traits.
P2: Prenatal testing involves the selective termination of individuals with undesirable genetic traits.
C: Therefore, prenatal testing is a eugenic practice.

As can be seen, it is quite obvious that the new eugenics is the same as the old eugenics and the goals shared are very similar. Thus, the only distinction between old and new eugenics is that for the new eugenics there is no state coercion for the use of the new genetic technologies to screen for undesired traits like diseases. In this regard, it is used negatively, but there is though the chance that it will be used positively. By “negative” and “positive” I’m referring to negative and positive eugenics.

Now, I can connect the arguments I’ve made and argue that eugenics is morally wrong and that it rests on the false premise of genetic reductionism.

P1: If prenatal testing is used to screen for diseases to abort babies, then it is a eugenic practice.
P2: If selective breeding or termination of individuals with undesirable genetic traits is a eugenic practice, then eugenics is based on the false premise of genetic reductionism.
P3: Eugenics that is based on the false premise of genetic reductionism ignores the complex interplay between genetics, environmental factors and other developmental resources and fails to fully appreciate the inherent worth and value of every human being.
C: Therefore, using prenatal testing to screen for diseases to abort babies is a form of eugenics that is based on the false premise of genetic reductionism and is morally wrong.

IQ, embryo selection and PGS

While we have already begun to implement such tools and methods in the public, a recent study concluded that testing embryos for complex traits like height and IQ is “premature”, with the top-scoring PGS embryos gain would be approximately equal to 2.5cm in height and 2.5 IQ points (Karavani et al, 2019). But these values were derived from PGS which were derived from GWAS, so it’s just based on correlation. Most authors of course assume that “intelligence” is “highly polygenic”, they need not only correlation, but a mechanism (Munday and Savalescu, 2021). Unfortunately, the eugenic dreams of IQ-ists to increase IQ through these methods won’t work. Since one’s IQ is a function of the type of psychological and cultural tools they are exposed to from birth, and the items on the test are biased towards a certain social class, there are known ways to increase IQ that don’t have anything to do with genetically reductionist GWAS/PGS/PGD pipe dream. The argument can be made like this:

P1: The potential gain of embryo screening for traits such as height and cognitive ability is not significant.
P2: The gain due to embryo screening for height and cognitive ability is small, with an average gain of only ≈2.5 cm for height and ≈2.5 IQ points for cognitive ability.
C: Therefore, there is no significant case for using preimplantation genetic diagnosis to select embryos for implantation based on height or cognitive ability.

Of course, this doesn’t mean that even if the so called gains were significant and that PGS were causal that we should use PGD to select those traits


Although it has been said that common arguments against genetic reductionism rest on a strong version of genetic reductionism/determinism, and so the arguments “are therefore unsound” (Resnick and Vorhaus, 2006). The kinds of arguments, assumptions and considerations in this discussion of genetic modification and PGD assume, also, any kind of genetic determinism of traits.

At the end of the day, methods like PGD can lead to the destruction of fetuses on the basis of its genetic constitution. Eugenic selection could also have unintended consequences in the future since genetic variance could be reduced which would impinge on one’s ability to choose a partner, so it would lead to a limitation in partners for future people. Irrespective of the moral arguments made here, I think that the open future argument makes the best case against genetic modification of humans. This will yet again be another argument from human autonomy. Not only will we be impinging on one’s individual autonomy, but we don’t even know what kind of traits could be desirable from a survival point of view in the future. So that’s another reason to not genetically modify embryos or to select certain embryos over others.

P1: Future people have a moral right to choose (or not) the characteristics of their own genome.
P2: Genetic modification of an embryo involves making choices about the characteristics of the future person’s genome.
C: Therefore genetic modification of an embryo is morally impermissible since it violates the moral right of the future person to choose (or not choose) the characteristics of their own genome.

While genetic reductionism is a form of biological determinism, there is also what is called epigenetic determinism. Any kind of reducing X to deterministic proclivities is false. Nevertheless, I have distinguished between the old and the new eugenics, and showed that the only difference between them is that in the new eugenics, there is no state-sponsored coercion or forced sterilization occurring. (Although that, sadly still happens today.) Since genetic reductionism is false, then any attempt to “defend eugenics” (Anomaly, 2018; Wilson, 2019; Veit et al, 2021) are doomed to fail. But genetic engineering “is objectionable because it represents a bid for mastery and dominion that fails to appreciate the gifted character of human powers and achievements” (Sandell, 2007).

Devestating Objections to the Rushton-Lynn Cold Winters Theory

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Cold winters theory (CWT) attempts to explain the variation in IQ scores between countries. According to the theory, what explains a suite of observed differences is differential evolution by natural selection in different environments. Due to the exodus out of Africa, this led to the colonization of new biomes with novel things that early Man would not have been accustomed to. Thus, they would then need to be able to adapt their actions and behavior to their new environment. Since they were in novel environments, early man would then need to acquire new skills to survive. So those who could not, had a lower chance to reproduce, and so, there was selection-for and selection-against certain traits. So, over time, this led to differences in the phenotype between groups that evolved in different environments, and the driver of this was natural selection. Hereditarians have said as much, and this theory is a cornerstone to their thinking. The observed differences, in order to be of any use to hereditarians, must be due to evolution, particularly due to evolution by natural selection.

However, although natural selection isn’t itself a mechanism (Fodor, 2008; Fodor and Piattelli-Palmarini, 2010), it is generally understood that natural selection actually decreases genetic variation in a trait (Howe, 1997: 70; Richardson, 2017: 46) . Thus, if the differences in IQ between races were due to natural selection, then there would be decreased, not increased, variability in IQ/intelligence between races.

Emil Kirkegaard has a good overview of the history of this theory. Nevertheless, I myself have made critiques of CWT, which rely on the fact that it makes no risky, novel predictions (contra Lynn). In this article, I will mount some more arguments against CWT, and I will further show how the logic for the theory crumbles due to the use of shoddy reasoning and the use of ad hoc hypotheses to save the theory from falsification. I will conclude that the CWT has no scientific value and is nothing more than a just-so story that explains what it purports to explain while not successfully predicting novel evidence.

Cold winter theory – Lynn

One of the earliest instance of CWT can be found in Wallace (1864). In his article, he states things that contemporary hereditarians would then argue. In 1987, Richard Lynn argued that the selective pressures of cold winters explains the high IQs of “Mongoloids” (Asians) (Lynn, 1987). Lynn states that the higher IQs of Asians can be explained by the selective pressures of cold environments. He posits adaptations that evolved in Asians, which cold winter environments then selected-for. In 1991, Richard Lynn argued that surviving in novel environments that our species didn’t evolve in led to selective pressures which increased the IQs of “Caucasoids” and “Mongoloids.” The two groups had to survive in cognitively demanding environments and, due to the cold, needed to create shelters, make clothes and fire along with hunting game. So this explains why the two groups have evolved greater intelligence than Africans. Although Ian Deary is himself an IQ-ist, he rightly states that Lynn’s theory is nothing more than a just-so story:

Another review of the thorny issue which Lynn deals with in the first paper may be judged worthwhile if there is a wealth of convincing new evidence, or a Flynn-like (1987) fine-toothcombing of the past evidence. Neither of these objectives is achieved. Therefore, the Pandora’s box has been opened once more, some may say, to no great purpose. What of Lynn’s evolutionary account of the origins of intelligence test score differences between groups? It puts me in mind of Kipling’s Just So stories. When one is more used to examining factor analyses or anova tables the type of evolutionary evidence that is offered here is difficult to evaluate. One suspects that there is an infinite number of more or less plausible historical accounts of the causes of racial differences in IQ test scores, and that all would leave aside uncomfortable facts (like the intelligence needed to exist in hot arid climates). The issue addressed in Lynn’s first paper is difficult enough, but the evidence is far too sparse to be telling the story of how the eskimo got his/her flat nose. (Deary, 1991: 157)

Thus, if this relationship were to hold, then those who experienced the harshest, coldest conditions should have the highest IQs. However, this is not what we see. Arctic people have IQs around 91, and so, this seems to be a piece of evidence against CWT. Lynn, though, has an ad hoc hypothesis for why they don’t have higher IQs—they had a small population size and so high IQ generic mutations didn’t have a large chance to appear and then become stabilized in the genome like they did for Asians (population size for Arctic people 56,000; for Asians 1.4 billion; Lynn, 2006: 157). So due to geographic isolation along with a small population size, Arctic people did not have the chance to gain higher IQs. This is nothing more than an ad hoc hypothesis—an ad hoc hypothesis is produced “for this”, and a hypothesis is ad hoc if it cannot be independently verified. It’s a case of special pleading, as Scott McGreal’s argues.

The fact of the matter about CWT, is that the conclusion was known first (higher IQs in certain geographic areas), and then a form of reverse reasoning was used in order to attempt to ascertain the causes of the observed differences between groups. This is known as reverse engineering, where reverse engineering is defined as “a process of figuring out the design of a mechanism on the basis of an analysis of the tasks it performs” (Buller, 2005: 92). This is also one of Smith’s (2016: 227-228) just-so story triggers:

1) proposing a theory-driven rather than a problem-driven explanation, 2) presenting an explanation for a change without providing a contrast for that change, 3) overlooking the limitations of evidence for distinguishing between alternative explanations (underdetermination), 4) assuming that current utility is the same as historical role, 5) misusing reverse engineering, 6) repurposing just-so stories as hypotheses rather than explanations, and 7) attempting to explain unique events that lack comparative data.

Lynn (1990) attempted to integrate gonadotropin levels, testosterone and prostate cancer into the theory, stating that by having fewer children and showing mote care to them, non-African populations then shifted to a K strategy, which then led to a concomitant decrease in testosterone and subsequently aggressive tendencies (Rushton, 2000: 263). However, this is based on the false assumption that testosterone is directly responsible for aggression, meaning that as testosterone increases so does aggression. They have the cause and effect backwards, though—aggression leads to an increase in testosterone, so Lynn’s explanation fails.

Rushton then comes along and champions Lynn’s “contributions to science” (Rushton, 2012), while also praising Lynn’s theory as explain why northerly populations evolved higher IQs and larger brains than southerly populations (Rushton, 2005), while making the grandiose claim that “documenting global race differences in intelligence and analysing how these have evolved may be his crowning achievement” (Rushton, 2012: 855). Rushton wrote an Amazon review of Lynn’s book, and then again in the white nationalist magazine VDare. Of course Rushton would go to bat for Lynn, since Lynn’s theory is a cornerstone of Rushton’s r/K selection theory, which is where we will now turn.

Cold winter theory – Rushton

Starting in 1985, Rushton began arguing that there was a suite of dozens of traits that the races differed on (Rushton, 1985). He collated his arguments in his first book, Race, Evolution, and Behavior (Rushton, 1995), and he argued that what explained the differences in these traits between his races were the selective factors that influenced and dictated survival in those environments. Rushton and Jensen (2005: 265-266; cf Andrade and Redondo, 2019) argued that there are genetically-driven differences in IQ scores between races (blacks and whites, in this instance), and one of the largest reasons for these differences was the different types of environments the two races were exposed to:

Evolutionary selection pressures were different in the hot savanna where Africans lived than in the cold northern regions Europeans experienced, or the even colder Arctic regions of East Asians. These ecological differences affected not only morphology but also behavior. It has been proposed that the farther north the populations migrated out of Africa, the more they encountered the cognitively demanding problems of gathering and storing food, gaining shelter, making clothes, and raising children successfully during prolonged winters (Rushton, 2000). As these populations evolved into present-day Europeans and East Asians, the ecological pressures selected for larger brains, slower rates of maturation, and lower levels of testosterone—with concomitant reductions in sexual potency, aggressiveness, and impulsivity; increases in family stability, advanced planning, self-control, rule following, and longevity; and the other characteristics listed in Table 3.

So this is where Rushton’s r/K selection comes in. He proposed that “some groups of people are more K selected than others” (Rushton, 1990: 137). So if some groups are more K selected than others, then some groups would have different trait values when compared to others, and this seems to support Rushton’s theory. However, Rushton’s theory can be explained environmentally, without appealing to genetics (Gorey and Cryns, 1995) and it also has not been independently replicated (Peregrine, Ember and Ember, 2003).

Devestating Objections to CWT

Objection 1: The fact of the matter is, when it comes to CWT, this is a perfect example of ideas and beliefs that shift with the time based on current observations. Aristotle argued that since the ancient Greeks had the middle geographic position between Asia and the rest of Europe, they were spirited and intelligent and therefore continued to be free while those who inhabited cold places like Europe lacked intelligence and skill, they had spirit while those in Asia were intelligent while being skilful in temperament, while also being subject to slavery. It was the Greeks who were right in the middle—they were just right, like Goldilocks—to have both all of the good and none of the bad traits they associated with those in other geographic locales. Meloni (2019: 42) cited one Roman officer who stated that recruitment of individuals from cold climates “as they had too much blood and, hence, inadequate intelligence. Instead, he argued, troops from temperate climates be recruited, as they possess the right amount of blood, ensuring their fitness for camp discipline (Irby, 2016).” This is solid evidence that who is or is not “intelligent” can and has changed with the times, along with other explanations of differences between people. This, then, proves the contingency of the concept of “more intelligent people”, and that people will marshal any kind of evidence for their pet theories at the time they have observed them and work backwards to form an argument, a kind of inference to best explanation. Thus, an evolutionary psychologist or IQ-ist transported back to antiquity would have formulated a different theory of intelligence, which obviously would have been at-odds with what they try to argue for today.

Objection 2: In 2019, I contrasted the CWT with the vitamin D hypothesis. I argued that there was one successful novel prediction made by the VDH—namely the convergent evolution of skin color in hominids that left Africa (Chaplan and Jablonski, 2009: 452), which was successfully predicted by Chaplan and Jablonski (2000). I wrote:

If high ‘intelligence’ is supposedly an adaptation to cold temperatures, then what is the observation that disconfirms a byproduct hypothesis? On the other hand, if ‘intelligence’ is a byproduct, which observation would disconfirm an adaptationist hypothesis? No possible observation can confirm or disconfirm either hypothesis, therefore they are just-so stories. Since a byproduct explanation would explain the same phenomena since byproducts are also inherited, then just saying that ‘intelligence’ is a byproduct of, say, needing larger heads to dissipate heat (Lieberman, 2015). One can make any story they want to fit the data, but if there is no prediction of novel facts then how useful is the hypothesis if it explains the data it purports to explain and only the data it purports to explain?

It is possible to think up any kind of story to explain any observation to give it an air of scientific objectivity. Of course it is possible to argue that other climates can select higher intelligence, as Anderson (1991), Graves (2002), and Flynn (2019) have argued. Sternberg, Grigorenko, and Kidd (2005) have also argued that it is possible to think of any kind of explanation/story for any kind of observed data. Nevertheless, the fact of the matter is this: There is no reason to accept the CWT, since there is no independent evidence for the theory in question.

Objection 3: If the Lynn-Rushton CWT were correct, then we would observe lower variation in IQ scores between whites and Asians, since it is well-accepted that natural selection reduced genetic variation in traits that are important for survival (Howe, 1997: 70; Richardson, 2017: 46). In the hereditarian conception, of course intelligence is important for survival, and so if the hereditarian argument for CWT is true, then we should observe lower variance in IQs in whites and Asians compared to blacks, but we don’t see this. (Also see Bird, 2020 for an argument against the hereditarian hypothesis, showing that there is no natural selection in blacks and whites on cognitive performance.)

Objection 4: Hereditarians have relied on the concept of heritability for decades. If T is highly heritable, then T has a genetic component and what explains the variance in T is genetics, not environment. Many critiques of the heritability concept have been mounted (eg Moore and Shenk, 2016), and they spell trouble for the hereditarian CWT and the hereditarian hypothesis as a whole. But these estimates are derived from highly confounded studies, and so the “laws” derived from them are anything but.

Objection 5: Rushton and Lynn posit that Asians are K- while Africans are r-selected. Rushton rightly stated that Africans endure endemic and infectious disease, which he wrongly stated was an r trait. He also stated that cold winters shaped K traits in Asians and European populations. However, based on the (accepted at the time) tenets of r/K selection, it would actually be Africans that are K and Asians that are r, since groups that move out of environments they evolved in and into new ones are freed from density-dependent control (Anderson, 1991: 59).

Objection 6: The irreducibility of the mental to the physical means that psychology can’t be an object of selection since it is not physical. Intelligence is posited as a psychological trait, so it cannot be selected. This is a devestating objection to not only the CWT but to most hereditarian hypotheses which reduce mental states to brain states or genes. Such irreducibility arguments make hereditarianism untenable.

Arguments against CWT

With all this being said, here are a few arguments derived from the discussions above. It is well-established that the CWT hardly had any evidentiary basis. It’s merely the argument of ideologues.

P1: If CWT were true, then there would be independent evidence for it.
P2: There is no independent evidence for the CWT.
P3: The correlation between race and IQ is better explained by social and environmental factors than by the CWT.
P4: The evidence cited in support of the CWT, including Lynn’s national IQ data, is fraudulent and lacks scientific rigor.
C: Therefore, the CWT is false.

Premise 1: This is a basic tenet of scientific explanation. Independent evidence refers to evidence not used in the construction of the hypothesis. The only evidence for CWT is the observation of differences in IQ between people that inhabit different geographic locations. So if CWT were true, it is entailed that there should be independent, novel evidence to support the hypothesis. It is evidence that isn’t based on the original assumptions or data used to construct the hypothesis. If there is, then that raises the probability that the state of affairs that is proposed is true. Independent, novel evidence is important, since it helps confirm or disconfirm a theory or hypothesis by providing additional support from sources that were not originally taken into account. Evidence is novel when it is not already known or expected based on prior knowledge or previous observations. So novel evidence would, in this instance, refer to evidence that supports the theory and is distinct from the evidence that is used to support it. So in order for CWT to be scientifically valid, there would need to be independent evidence that shows a direct causal link between intelligence and cold winters.

Premise 2: This is a denial of the claim that there is independent evidence that supports CWT, on the accepted definition of “novel, independent evidence.”

Premises 3 and 4: These two premises are linked—access to education along with nutrition better explains the relationship between latitude and IQ. There is also the fact that Lynn’s “national IQs” are fraudulent (Sear, 2022). Thus, there is no evidentiary reason to accept Lynn’s IQs (the only reason is bias and that it “explains” the differing civilizational states of different races). It’s merely working backwards (returning to reverse engineering) since they have their conclusion in mind and then construct an argument to prove their already-held conclusion.

So the Conclusion follows—CWT is false since there is no independent, novel evidence for it. Therefore the only reason to believe it is bias in thinking against groups of people.

P1: The CWT suggests that differences in average IQ scores between racial groups can be largely explained by differences in the coldness of the winter climates that these groups evolved in.
P2: All of the evidence used to support the CWT is based on previously existing data, such as Lynn’s national IQ data or historical temperature records.
P3: There is no new independent evidence that supports the CWT beyond this existing data.
C: Thus, there is no novel, independent evidence for the CWT.


P1: If there is new independent evidence for the CWT, then the CWT can be independently supported.
P2: There is no novel independent evidence for CWT beyond the existing data.
C: So the CWT cannot be supported by new independent evidence.

These arguments are valid and I hold them to be sound, based on the discussion in this article and my previous articles on the matter of CWT and the prediction of novel facts of the matter.


We don’t need evolutionary stories to explain IQ differences between countries (Wicherts, Borsboom, and Dolan, 2010). Lynn’s national IQ data is highly suspect and should not be used (Sears, 2022). High intelligence would be useful in all environments. The Rushton-Lynn CWT states that those who migrated to more northerly, colder biomes needed to plan ahead for the winter, and they would also need to plan and create hunting parties to procure food. This, of course, is ridiculous. Because you need to plan ahead to survive anywhere. Moreover, Will et al (2021) state that their:

analyses detected no such association of temperature with brain size. … These results suggest that brain size within Homo is less influenced by environmental variables than body size during the past 1.0 Ma.

This is of course a huge strike against the Rushton-Lynn CWT. Anthropological evidence also conflicts with the CWT (MacEachern, 2006).

Since I have shown that the evidentiary bases of the CWT doesn’t hold, then it isn’t logical to hold the belief that the CWT is true. Views like this are expressed in Rushton (2000: 228-231)Jensen (1998: 170, 434-436) and Lynn (2006: Chapters 15, 16, and 17). Since the main proponents of the model hold eugenist ideas, then it can be posited that they have underlying alterior motives for pushing this theory. Even a claim that there is “molecular genetic evidence” for CWT fails, due to, again, the irreducibility of the mental.

Nevertheless, there is no novel, independent evidence for the belief that cold winters shaped our minds and racial differences in psychological traits after the exodus out of Africa. There can be no evidence for it since we lack time machines and we can’t deconfound correlated traits. So these considerations point to the conclusion that the CWT is a mere story based on data which was then used to work backwards from an already-held conclusion. Thus, CWT is false.

Rushton, Lynn, Kanazawa (2008, 2012), (Kanazawa assumed a flat earth in his 2008 paper; Wicherts et al, 2012) Hart (2009), and Winegard, Winegard, and Anomaly (2020) therefore, are nothing more than just-so storytellers since they lack novel evidence for their assertions. So the so-called argument for evolutionary differences in intelligence/IQ rests on a house of cards that is simple to push over. The six objections laid out in this article are devestating for the CWT. There never was any evidentiary support for CWT—the kind that scientific hypotheses need in order to be valid, it’s merely an ideological series of statements, not an actual scientific hypothesis.

The Distinction Between Psychological and Racial Hereditarianism

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The hereditarian hypothesis posits that genetic/biological factors are responsible for IQ (“intelligence”) and other psychological traits. The claim is basically, IQ is heritable. It is heritable on the basis of twin, family and adoption studies, along with results from GCTA, GWAS and other newer tools that were created in order to lend credence to the twin, family and adoption estimates.

I have distinguished before between what I call “psychological hereditarianism” and “racial hereditarianism.” In this article, I will distinguish between the two more, and while psychological hereditarianism isnt necessarily racist, it can be used for racist aims.

Psychological hereditarianism

Psychological hereditarianism is the belief that psychological differences between people are due largely to genetic or biological factors rather than environmental ones. Claims such as this have been coming from twin studies for decades, and it has been commonly said that such studies have proven that aspects of our psychological constitution are genetically heritable, that is genetically transmitted.

Four kinds of studies exist which lend credence to psychological hereditarianism—family studies, twin studies, adoption studies, and GWAS.

Family studies

Family studies examine the similarities in individuals of the same family when it comes to their cognitive abilities (scores on IQ tests). These studies show that those who share more genes have similar scores than those who don’t. To the hereditarian, this is evidence for their hypothesis that genetic factors contribute to psychological traits and differences in them. Correlations are used to measure the strength of the relationship. An expected value of 50 percent (.5 correlation) between siblings is expected, as they share half of their genes. The correlation that is expected between unrelated individuals is 0, since they presumably don’t share genes (that is, they’re not from the same family).

However, there is one huge issue for family studies—environmental confounding. While people in the same families of course share the same genes, they also share the same environments. So family studies can’t be used as evidence for the psychological hereditarian hypothesis. Behavioral geneticists agree that these studies can’t be used for the genetic hypothesis for psychological traits, but they disagree with the implications of this claim for the next thing I will discuss.

Twin studies

Twin studies again use the correlation coefficient and compare twins raised together or “apart”, to then argue that genes play a substantial role in the etiology of psychological traits like “IQ.” These studies have found that identical twins have more similar cognitive abilities than fraternal twins, which to the twin researchers points to the conclusion that genetic factors contribute to substantially to psychological traits like IQ and other traits. However, the main limitation of such studies comes down to twins reared together. It is assumed that identical and fraternal twins share equally similar environments. This claim, as admitted by twin researchers themselves, is false (Joseph, 2014; Joseph et al, 2015). They then pivot to two arguments—Argument A and Argument B (Joseph et al, 2015)—but A is merely circular and B needs to be shown to be true by twin researchers, that is, they need to rule out and identify trait-relevant factors.

Limitations of twin studies include: not being generalizable to the general population; they’re based on many of the same (false) assumptions that were originally formulated on the 1920s at the advent of twin studies; the findings are misunderstood and blown out of proportion; they lead to volunteer/recruitment bias; and it doesn’t allow the disentangling of G and E since they interact (Sahu and Prasuna, 2016). The “advantages” of these studies aren’t even advantages, since it is conceptually impossible to tease out the relative contributions of G and E to a trait. Nevertheless, twin studies don’t show that psychological hereditarianism is true, and perhaps the most famous twin study of all—the MISTRA—hid the data of its fraternal twins (the controls). Joseph (2022) has an in depth critique of the MISTRA and why conclusions from it should be outright rejected.

Adoption studies

The issues with adoption studies are large, as large as the issues with twin studies. Assignment of adoptees to homes isn’t random, they look for homes that are closer to the homes of the biological mother. This restriction of range reduces the correlation between the adopted children and adopted parent. Adoptees also experience the womb of their biological mother’s (obviously). The adoptive parents are also given information about the adoptee’s family, and this along with conscious and unconscious treatment of the adoptee may help in making the adopted child different (see Richardson and Norgate, 2006; Moore, 2006; Joseph, 2014). Basically, the additive gene model is false, and adoptions don’t simulate a random design.


The larger issue at hand here is how the aforementioned have been used to search the genome for the genes that lead to the high heritabilities of IQ. This has then led to the creation of polygenic scores. These studies examine the association between genes and IQ in large samples of individuals. These studies compare the genomes of people who have a certain trait, and they then look for correlations between the genes and the traits in that population. GWASs may miss rare genes with large effects. These studies only merely show associations between genes and traits, not causation. Another issue is population stratification—which is “differences in allele frequencies between cases and controls due to systematic differences in ancestry” (Freedman et al, 2004). GWAS, then, are compromised by this stratification, and attempts to correct for it have been found wanting (Richardson, 2017; Richardson and Jones, 2019; Richardson, 2022). There is also the fact that larger sample sizes won’t help the endeavor of proving that genes contribute to psychological traits—since large databases contain arbitrary correlations, then by increasing the sample size this then highly increases the chance for spurious correlations (Claude and Longo, 2017). At the end of the day, the associations found are weak and could possibly even be meaningless (Noble, 2018). There is also the fact that PGS ignore development and epigenetics (Moore, 2023). Basically, genes don’t work how hereditarians need them to.

The fact of the matter is, these research methods continue to push the false dichotomy of nature vs nurture (the first instance of which appeared in a 13th century French novel on gender). There is also the fact that the “laws of behavioral genetics” rest on twin, family and adoption studies. So if the assumptions of these studies are false, then there is no reason why we should accept the conclusions from them. There are no “laws” in biology, especially not the “laws of behavioral genetics.”

Racial hereditarianism

Racial hereditarianism, on the other hand, is the belief that there are inherent, genetic differences in cognitive ability and other psychological traits between racial and ethnic groups. One—most often unstated—claim is that one group of people are inferior to another (as can be evidenced by the labels of the categories used by Terman), and it has been used to justify discriminatory policies and forced sterilization of people found to have lower IQs. Genetic inheritance explains the how and why of some races having higher IQs than others.

The most famous racial hereditarians are Lynn, Rushton, and Jensen. Over the last 50+ years, these authors have dedicated their lives to proving that certain racial groups have higher IQs than others for genetic reasons. These differences aren’t due just to environment or culture, they say, there is a significant genetic component to the differences in scores between racial and ethnic groups. Since IQ is related to success in life—that is, since IQ is needed for success—then what explains average life outcomes between racial and ethnic groups are their IQs and the ultimate cause is their genes which ultimately cause their IQ scores. Due to the strength of genetic factors on IQ, they say (like Jensen), social programs are doomed to fail.

The argument against psychological hereditarianism and racial hereditarianism

The argument against these is simple—the mental is irreducible to the physical and so, while there are of course correlations between “traits” like IQ and genes, that doesn’t mean they’re causal and due to the irreducibility of the mental to the physical, we can’t find what they need us to find in order to prove their theses.

P1: If racial hereditarianism is true, then cognitive differences between racial groups are primarily due to genetic factors.
P2: There is no empirical (or logical) evidence that supports the claim that cognitive differences between racial groups are primarily due to genetic factors.
C: Thus, racial hereditarianism is false.

P1: If psychological hereditarianism is true, then individual differences in psychological traits are due primarily to genetic factors.
P2: There is no empirical (or logical) evidence that supports the claim that individual differences in psychological traits are primarily due to genetic factors.
C: Thus, psychological hereditarianism is false.

The irreducible complexity of mental states/psychological traits means that it’s impossible for them to be caused or influenced by genetics meaning that both psychological and racial hereditarianism are false. Both psychological and racial hereditarianism, as their unstated assumptions, rely on a type of physicalism to where mental states can be reduced to genes or the brain/brain states. Both kinds are a physicalist theory of mind, and since physicalism is false so are psychological and racial hereditarianism. This is yet more evidence that hereditarianism is false and so it strengthens the argument for banning IQ tests.


Both forms of hereditarianism I’ve discussed here are false, and ultimately they are false since the mental is reducible to the physical. Both of them, however, are inherently reductionist and attempt to reduce people to their genes or their brains. They have, in the past, led to the sterilization of certain people deemed “unfit.” Of course, the hereditarian hypothesis isn’t necessarily racist, though it can be used for racist aims. It can also be used for classist aims. It can be launched at whatever a society deems “unfit”, and then they can try to correlate biological factors with what they deem “unfit.” The very notion that certain races are superior or inferior on intelligence is a form of racism. Such ideas have been used in the recent past in order to justify discriminatory policies against people. So while the psychological hereditarian hypothesis may not be racist (it could be classist, though), how it has been articulated and then even put into practice is inherently racist. In any case, here’s the argument that the hereditarian hypothesis is a racist hypothesis.

P1: If the hereditarian hypothesis is true, then differences in IQ and other traits among racial and ethnic groups are primarily due to genetic factors rather than environmental or social factors.
P2: Differences in IQ and other traits among racial and ethnic groups are not primarily due to genetic factors, but rather environmental or social factors.
C1: Therefore, the hereditarian hypothesis is not true.
P3: If the hereditarian hypothesis is not true, then it cannot be used to make claims about inferiority or superiority.
P4: The hereditarian hypothesis has, historically been used to make claims about the innate superiority or inferiority of certain racial groups, thereby justifying discriniminatory policies and harmful stereotypes.
C2: Therefore, the hereditarian hypothesis is a racist hypothesis.

I’ve shown how P1 and P2 are true exhaustively, so C1 follows from those 2 premises. P3 follows from the conclusion in C1, and P4 is a historical fact. So C2 follows. So by referring to the hereditarian hypothesis as a racist hypothesis, I mean that the hypothesis has been entangled with racist and discriniminatory policies since it’s inception.

So I have articulated a distinction between psychological and racial hereditarianism, where psychological hereditarianism is about the genetic transmission of psychological traits and where racial hereditarianism is the belief that there are inherent racial differences in psychological traits due to genetic differences between groups. While there are of course genetic differences between groups and individuals, it doesn’t follow that said genetic differences cause differences in psychological traits, which is the main claim of hereditarianism. The issue of the reducibility of the mental isn’t an empirical matter, it’s a conceptual one. So the hereditarian hypothesis, therefore, is refuted on conceptual, a priori grounds.

A Priori and Empirical Arguments for Multiple Realizability

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What is the multiple realizability argument?

The multiple realizability argument (MRA) is an argument directed at type-identity theories of mind, while being used for and against functionalist theories of mind. (I think Ross’ 1992 argument in Immaterial Aspects of Thought and Feser’s 2013 arguments refute functionalist theories.) First formulated by Hilary Putnam in 1975, the argument he formulated can be put like this:

P1. If type-physicalism is true, then every mental property can be realized in exactly one physical way.
P2. It is empirically highly plausible that mental properties are capable of multiple realizations.
C1. It is (empirically) highly plausible that the view of type-physicalism is false (modus tollens, P1, P2). (From Just the Arguments, 81. Putnam’s Multiple Realization Argument against Type-Physicalism)

P1 states the scope of type-physicalism—that all mental states are realizable in one and only one physical way. P2 states that it is probable that mental properties are capable of multiple realizations. This premise is an empirical one, and so we need evidence to believe it. Then, the conclusion is that type-physicalism is false sine mental states are multiply realizable. Quite obviously, this argument shows that mental states don’t reduce to brain states, which means that physicalism is false. Since P2 needs defense, I will defend it in this article while giving my own formulation of the MRA.

Here is my formulation of it:

P1: If mental properties were identical to physical properties, then any change in one entails a change in the other.
P2: Mental properties can change without any corresponding change in physical properties.
C: So mental properties aren’t identical to physical properties.

As you can see, like Putnam’s formulation, P2 is an empirical claim and so needs empirical support. So if one mental state can be realized in multiple ways, then type-physicalism (mind-brain identity) is false. I will spend the rest of this article arguing for the truth of P2 and then provide an argument from analogy showing that mental states are multiply realizable.

An a priori argument for multiple realizability

If the MRA were true, then there would be evidence of a specific mental state that is realized in multiple physical ways. While empirical evidence is irrelevant to metaphysical possibility (and to concepts), multiple realizability can be known a priori. Before I give the empirical argument from analogy for multiple realizability, I will give the a priori argument.

P1: Mental states and processes exhibit certain characteristic features and properties like intentionality, subjectivity, and causality.
P2: If mental states are multiply realizable, then they are not reducible to their underlying physical properties.
C: Thus, mental states and processes are not reducible to their underlying physical properties.


P1: M has properties P1, P2, P3…
P2: If M is multiply realizable, then M is not reducible to it’s physical properties.
C: Therefore, M is irreducible to its physical properties.

Premise 1: Mental states and processes are characterized by what they do rather than what they’re “made of.” Intentionality is the ability for mental states to be “about” things, while directed at objects, events or states of affairs like when a belief or proposition is about a certain end goal. So M properties aren’t reducible to any P properties, and intentionality is a property of mental states which set them apart from physical states, since purely physical things can never have the ability to intend. Subjectivity refers to the fact that mental states are experienced through a first-personal perspective which can’t be observed or measured by others. This property sets M states apart from P states, since physical states can be studied and observed from a third-personal perspective. So while we can study brain states, since mental states don’t reduce to brain physiology, then by studying brain states we aren’t studying the mind. Lastly the property of causality refers to the fact that mental states and processes have causal effects on action and behavior, cognition and other mental states and processes. So the distinctive role that mental states and processes play in generating action, behavior, and cognition cannot be captured by studying the brain or the body.

Premise 2: This premise highlights the fact that multiple realizability implies that mental states can be realized in a multitude of physical states and processes without any loss of mental properties. So the Conclusion follows that mental states and processes are irreducible to their underlying physical properties.

So if mental states and processes have characteristic features that distinguish them from other kinds of states and processes, and if they can be realized by multiple physical systems, then they cannot be reduced to one physical system.

Defending P2: Empirical evidence for multiple realizability

The way that Putnam and I have formulated the argument for MR is an empirical claim. So empirical claims require empirical evidence. While the previous argument was a priori, it could therefore be argued without empirical evidence.

The example of visual perception. Most animals on earth have vision. The visual systems of animals have evolved to help them survive in their ecologies. Humans have three cone types in their eyes which allows them to see a range of colors. On the other hand, some birds have four cone types which allow them to see a wider range of color than humans, and the fourth cone thsg birds have allows them to see more colors than humans (Stoddard et al, 2020). Bats have evolved eyesight that allows them to see in low light environments, while eagles have evolved eyesight that allows them to see objects at great distances. So despite differences in the visual systems between animals, they can all recognize objects and visually navigate their ecologies. So different animals have evolved different vision systems that help in a certain niche. Furthermore, different types of photoreceptors have evolved in different animals, with different connections between the eye and the brain, which began evolving around 600 million years ago, with the Cambrian explosion leading to body plans and systems which then supported vision (Lamb, Pugh Jr, and Collin, 2008; Lamb, Collin, and Pugh Jr, 2011; Asteriti, 2015). These photoreceptors come in two kinds—ciliary type (c-type) or rhabdomeric type (r-type); vertebrates seek to have a unique mix of these cone types which allow a wide range of vision (Marshedian and Fain, 2017). Certain eye structures have also evolved independently (Land and Nilsson, 2012). So different animals have different numbers of photoreceptors and cones, which help them to visualize their environment; the diversity of rods and photoreceptors in the animal kingdom is vast (Piechl, 2005). Thus, the evidence cited here shows that different animals have differently-evolved visual systems, but they can still visualize their environments even though the physical systems that allow it are different.

The brain’s ability to compensate from injury and the brain’s of athletes and musicians. After a traumatic brain injury occurs, the brain—being plastic—can rewire itself to carry different functions after an injury. For example, in the blind, the visual cortex is repurposed and processes tactile and auditory stimuli (Elbert et al, 2002; Lane et al, 2015; Gori et al, 2019). The primary motor cortex in musicians is larger than non-musicians, and this is due to constant practice on their instrument of choice (Toyka and Freund, 2006; Watson, 2006; Olszewska et al, 2021). Basketball players have larger cortical areas associated with visual processing and attention (Kim et al, 2022) along with athletes having different cortical neuronal networks than novices (Tan et al, 2017). This then is solid evidence for the claim that learning new skills and continously performing them at an expert level leads to changes in the brain (Park et al, 2015). Further, when it comes to the brain’s ability to heal from an injury, it has been shown that if a certain brain area is impacted, other parts of the brain will pick up the slack of the injured part, which shows the plasticity of the brain and the brain’s ability to compensate for an injury to it by directing and making new neural pathways to carry out new tasks (Nishimura et al, 2009; Su, Veeravuga, and Grant, 2016; Hylin, Kerr, and Holden, 2017). Thus, the evidence cited here shows how the brain can adapt to tasks that a person performs, and how it can adapt to changes to it (like injury) and even repurposing certain parts of itself in people with certain disabilities. This, like the example of visual perception, lends further support for the claim that different physical systems can perform the same mental function.

Brain-computer interfaces. Lastly, we have brain-computer interfaces. These interfaces “acquire brain signals, analyze them, and translate them into commands that are relayed to output devices that carry out desired actions” (Shih et al, 2012). These interfaces allow humans to control things with their thoughts, bypassing the need for physical interfaces; this technology also allows individuals to control certain kinds of devices using brain waves using their mental intentions (Mak and Wolpaw, 2010). People with these interfaces can control prosthetic limbs (Mischenko et al, 2017; Murphy et al, 2017; Asanza et al, 2022). These interfaces have also been explored to give people the ability to communicate with speech again (Brumberg et al, 2010). This also supports MR since brain-computer interfaces which use EEG to record brain activity could translate mental states into movements while interfaces that use implanted electrodes may allow an individual to control a robotic arm. Thus, the development of this technology shows that different mental states can be realized in different physical systems which is then dependent on the type of interface used.

Strappini et al (2020) provide yet more empirical support for MR. They write:

Here, we illustrate some cases that provide empirical evidence in support of MRT. Recently, it has been proposed that foveal agnosic vision, like peripheral vision, can be restored by increasing object parts’ spacing (Crutch and Warrington, 2007Strappini et al., 2017b). Agnosic fovea and normal periphery are both limited by crowding, which impairs object recognition, and provides the signature of visual integration. Here, we define a psychological property of restored object identification, and we cross-reference the data of visually impaired patients with different etiologies. In particular, we compare the data of two stroke patients, two patients with posterior cortical atrophy, six cases of strabismic amblyopia, and one case with restored sight. We also compare these patients with unimpaired subjects tested in the periphery. We show that integration (i.e., restored recognition) seems to describe quite accurately the visual performance in all these cases. Whereas the patients have different etiologies and different neural correlates, the unimpaired subjects have no neural damage. Thus, similarity in the psychological property given the differences in the neural substrate can be interpreted in relation to MRT and provide evidence in its support

While Booth (2018: 143-144) uses the example of multilingualism to support MR:

First, there are multiple ways of speaking a second-language, based on difference between high proficiency early and late bilinguals. Second, there are multiple ways of being a speaker of a given language, specifically as a monolingual or bilingual speaker of that language, where the language is the bilingual speaker’s L1. These examples meet the conditions advanced by Polger and Shapiro for examples of multiple realization, and should therefore be accepted as genuine cases of multiple realization.

Now that I have given a good overview of the evidence in support of MR, I will not provide the argument.

The empirical argument from analogy for multiple realizability

P1: Different animals have evolved different vision systems to suite their ecologies.
P2: Humans have a trichromatic visual system while some birds have tetrachromatic visual system while some insects have compound eyes.
P3: Despite differences in these visual systems, these animals all are able to perform similar visual tasks, like spatial navigation and object recognition.
P4: Studies of brain damage and neuroplasticity show that different brain regions can take on different functions after injury or training, like blind people using the visual cortex for auditory processing, muscisians having larger motor areas for finger control, and basketball players having larger cortical areas associated with visual processing and attention.
P5: The development of brain-computer interfaces show that mental states can be translated into different forms of output, like movement, speech, and text, using different physical devices.
C: Thus, multiple realizability is true, since the mental state of visual perception (and other mental states) can be realized in different physical systems without affecting functioning.

P1: If mental states can only be realized in a single physical system, then all animals with similar cognitive tasks should have identical neural structures.
P2: Different animals have different neural structures for performing similar cognitive tasks, like visual perception.
C: Thus, mental states cannot be realized in a single physical system.

P1: If mental states can only be realized in a single physical system, then all animals with similar cognitive tasks should have identical neural structures.
P2: If all animal with similar cognitive tasks have identical neural structures, then different animals should not have different neural structures for performing similar cognitive tasks.
P3: Different animals have different neural structures for performing similar cognitive tasks, like spatial navigation, object recognition and visual perception.
C: Thus, mental states cannot be realized by a single physical system.


I have provided both an a priori and a posteriori argument for the MRA. The a priori argument shows that multiple realizability is metaphysically possible, while the empirical evidence I have cited along with the empirical premises in my arguments have shown that multiple realizability is an empirically defensible position. It seems to me that it is intuitive that different mental states can be realized by different physical systems and not only one kind of physical system.

The a priori argument shows that mental states and physical states have different properties; physical states cannot have the properties that mental states have. So this shows that it’s metaphysically possible the MR is true, while the empirical evidence and arguments I have mounted show that it is true in our world as well. Mental states can’t be reduced to physical states, mental states are causally efficacious, and there are multiple ways to achieve the same cognitive function, like visual perception across the animal kingdom. The example of visual perception of different animals, studies of athletes, musicians, and people with traumatic brain injuries, and even brain-computer interfaces show that different mental states can be realized in multiple physical ways.

So if this is true, then multiple realizability is true. If multiple realizability is true, then type-physicalism is false, and therefore identity theories of mind need to find another avenue to prove their thesis. Mind-brain identity is clearly false; mind doesn’t reduce to brain and mental states can be realized by different physical systems. This is yet another argument against physicalism—the attempted reduction of mind to brain. Physicalism is quite clearly false.

There is No Such Thing as a “Male” and “Female” Brain

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Almost seven years ago I argued that there is such a thing as a “male” and “female” brain. Now, I’m not so sure on that belief. Because a claim like that reduces to the claim that there are two different KINDS of brain—make and female. This, though, is basically a mereological fallacy. Brains aren’t gendered/sexed, people are. Brains don’t have genders, people have genders. This doesn’t mean that there are no sex differences in the brain, that claim would be ridiculous. But the actual claim—a claim that I think is perfectly defensible—is that there ARE NOT two different kinds of brain. This is the conclusion that I will argue for in this article.

The brain mosaic

Questions like “Is the brain gendered?are the wrong kinds of questions to ask. Not only is it implying that there is more than one kind of brain, it is also implying that the brain is itself gendered. The claim that the brain is gendered is patently false; brains don’t have genders, people have genders, and people aren’t—nor do they reduce to—their brains. Therefore brains aren’t gendered.

When does a feature of a brain count as that which is typical of a male brain and vice versa for women? How many of these differences would there need to be in one brain to designate that brain as male or female? Of course there are average differences which I don’t think anyone would deny, but these average differences between brains wouldn’t license the claim that there are two different kinds of brain just like the fact that there are average differences in hearts between men and women don’t license the claim that there are two different kinds of heart. The only clear-cut average difference between the brains of men and women are that of size—women’s brains are about 11 percent smaller than men’s when body size is accounted for (Eliot et al, 2021). But mere size differences, also, do not license the claim that there are two different kinds of brain. For there to be male and female brains—two types of brain—there needs to be a property or set of properties which are exclusive to the two brains, but there are no such properties. Again, no one denies average sex differences, what is denied is that there are two different kinds of brain.

In recent years, talk in the neurosciences have shifted away from such a binary claim to that of mosaicism (Joel, 2011, 2012, 2021; Joel et al, 2015). Fine, Joel, and Rippon even have an explainer about sex, gender, brains and behavior. Joel et al (2015) analyzed four datasets of 1400 individuals examining the size and characters of brain regions that show the largest sex differences. They found substantial overlap between features, and that, on each end of the distribution, there were more males and more females, respectively. However, they had a novel finding: Many of the brains that were analyzed had many components of each “kind” of brain—they contains a mosaic of each of the ends of the distribution (male and female). Thus, the claim that brains are a mosaic or intersexed are true. So sex doesn’t determine brain type and, even though there are average differences between men and women, these average differences don’t add up to the claim that there are two different kinds of brain. Sex is dimorphic, but brains aren’t—brains are monomorphic.

Monomorphic not dimorphic

Sexual dimorphism is where the genders of a specific species have differences that aren’t solely (that is, not related to) due to their sexual characteristics. Monomorphic species, though, are similar in everything but their sexual characteristics. There is only one form with all individuals in that species having the same physical characters with little to no variation in them. So the claim that brains are dimorphic means that there are two kinds of brain—meaning, male and female. These terms (monomorphic and dimorphic) refer to variation in traits, with the term monomorphic referring to little or no variation while the term dimorphic refers to a situation in which there is noticeable variation. Certain bird species have different physical characteristics such as sex-specific markings, size differences and color differences which would mean they are dimorphic. On the other hand, other kinds of bird species may have the same kinds of physical characteristics meaning they are dimorphic.

If there is only one form of trait in a population, then the population is monomorphic. If there are two distinct forms of a trait in a population, then that population is dimorphic. Thus if there is little to no variation in the expression of a trait within a population then that population is monomorphic; if there is noticeable variation in the expression of a trait in a population then that population is dimorphic.

Eliot et al (2021) showed that brains aren’t dimorphic, they are monomorphic. The only reliable difference between the two are that of brain size, with women having an 11% smaller brain than men, which is smaller than that of the heart, lungs, and kidneys. Therefore, once brain size is accounted for, there are little no variation between brains (Eliot et al state the few reliable differences between brains are byproducts of brain size, so brain differences between sex/genders “explains” 1 percent of the total variance which means that brain differences which could be attributed to sex and gender are minuscule compared to individual variation.)

But for all the surplus of brain-level data on male-female difference, surprisingly few clear findings have emerged, and even less to justify labeling the human brain as “sexually-dimorphic.” Nor does anything in this massive data collection actually explain male/female differences in psychology or mental health (De Vries and Södersten, 2009Hirnstein et al., 2019) in spite of decades of such promise. To the contrary, the data show that male and female brains are overwhelmingly similar, or monomorphic, and suggest that finding such neural correlates will more fruitfully be achieved through study at the individual, as opposed to s/g group level.

Rather, a picture is emerging not of two brain types nor even a continuous gradient from masculine to feminine, but of a multidimensional “mosaic” of countless brain attributes that differ in unique patterns across all individuals (Joel et al., 2015). Although such differences may, in a particular sample, sum up to discriminate male from female brains, the precise discriminators do not translate across populations (Table 7; see also Joel et al., 2018Sanchis-Segura et al., 2020) so are not diagnostic of two species-wide types. In this sense, the brains of male and females are not dimorphic (like the gonads) but monomorphic, like the kidneys, heart and lungs, which can be transplanted between women and men with great success. (Eliot et al, 2021)

Mccarthy and Arnold (2011) explain why the belief that there are sex-specific circuits, which is due to the investigation of a small number of dimorphisms in the brain:

The repeated investigation of a relatively small number of sexual dimorphisms may have contributed to the false impression that a few discrete male or female circuits sit in an otherwise sexually monomorphic brain. The notion that for specific behaviors there is a discrete male neural circuit versus a discrete female neural circuit remains widely held despite a lack of empirical evidence of the existence of either.

The argument against the “two kinds of brain” argument

In this section, I will synthesize the preceding sections into an argument which argues that there aren’t two kinds of brain, male and female.

P1: If there are two kinds of brain (male and female) then there should be clear and distinct differences in brain structure and function between men and women.
P2: Studies have shown that there is a wide range of variation in brain structure and function among individuals of the same sex and also between men and women.
C1: Therefore, the available evidence doesn’t support the claim that there are clear and distinct differences in brain structure and function between men and women.
P3: The claim that there are two kinds of brain (male and female) is based on the assumption that there are clear and distinct differences in brain structure and function between men and women.
C2: Therefore, the claim that there are two kinds of brain (make and female) is not supported by available evidence.

Premise 1: This premise is based on the assumption that male and female brains are fundamentally distinct from each other, to such an extent that they can be categorized into two separate categories. There is, though, much overlap between the structure and function between brains belonging to men and brains belonging to women. For example, the Joel et al (2015) study cited above concluded that there is no such thing as a “male” and “female” brain, but there is a continuum of brain characteristics which are influenced by G and E factors. Rippon et al (2014) don’t argue that there are no differences in brain structure and function between sexes, but they do argue that such differences don’t license the claim that there are two forms—kinds—of brain. It is, again, important to note that none of these researchers argue that there are no sex differences; the claim is that these sex differences don’t add up to make “male” or “female” brains, they don’t belong to two different categories. Joel and Fausto-Sterling (2016) write:

We argue that the existence of differences between the brains of males and females does not unravel the relations between sex and the brain nor is it sufficient to characterize a population of brains. … Studies of humans further suggest that human brains are better described as belonging to a single heterogeneous population rather than two distinct populations.

Premise 2: The references on the brain mosaic back up P2. The differences that do exist are small (as noted by Eliot et al, 2021) and these differences do not support that claim that human brains are dimorphic. There is much overlap between brains of men and women and even significant variation in brain function and structure between individuals of the same sex.

Conclusion 1: Based on the two previous premises, the claim that human brains are dimorphic are clearly false. Differences are not clear-cut (and what differences do exist are small) and there is no one property or set of properties between brains that would designate one “male” and another “female.”

Premise 3: P3 is based on the history of this kind of research, in which it was assumed that there are two different kinds of brain—male and female. Jordan-Young and Rumiati (2012) argue that much of the research on sex differences in the brain is based on the binary assumption—since sex is binary, then the brains inside of the heads of the individuals must be sexed too. They assume that such differences exist in the brains exist and then go looking for them. Of course, more often than not, if you’re looking for something you’re going to find it. At the end of the day, the fact that sex and gender (s/g; Eliot et al, 2021) are so tightly interwoven (but still distinct) that even if there are biological differences, untangling them will be next to impossible, just like when it comes to heritability and the nature-nurture debate.

Conclusion 2: This conclusion logically follows from P3, since the claim that there are male and female brains is based on an outdated and oversimplified understanding between biology (brain) and sex. Any differences that do exist are small, influenced by numerous factors, and fall along a continuum, not a dimorphic binary.

So it thusly follows that there are not two different kinds of brain; the dimorphic assumption is false and brains, like other internal organs, are monomorphic.

Gender isn’t natural

Here, I have two arguments. One that establishes that gender and sex aren’t the same, and another that establishes that gender is not natural (it is social).

P1: If gender and sex are the same, then the characters and roles associated with being male and female are biologically determined.
P2: The characters and roles associated with being male and female are not purely biologically determined.
C: Thus, gender and sex are not the same.

P1 is based on the assumption that if g and s are the same, then all characters associated with male and female are biologically determined. Gender is a social construct which changes with the times and is different across cultures and time periods. (Like, for example,) So this indicates that such differences are not solely biologically determined. P2 states that gender roles are context- and time-sensitive. So roles and expectations of men and women are not solely biologically determined. The conclusion then logically follows: If the differences between men and women aren’t purely biologically determined, then gender doesn’t reduce to biology. So sex and gender are different because the characters and roles of men and women aren’t purely biologically determined, which means that gender isn’t reducible to biology.

Now here is my argument that gender is not natural, meaning it is social:

P1: All things that are “natural” are socially unmediated and inevitable (all A are B).
P2: Gender is socially-mediated and not inevitable (C is not B).
C: Therefore, gender is not natural (C is not A).

I think P1 is the only premise that one would reject. But to best defend P1, I only need to appeal to the definition of “natural.” “Natural” refers to anything that exists in the world independent of human society, culture, or intervention. Natural phenomena aren’t socially-mediated meaning that they aren’t shaped by human norms, values or practices and are inevitable due to certain physical laws. By “socially unmediated” I mean a phenomenon which isn’t dependent on human values, norms, or practices which occur independent of human intervention which are not subject to variation or change based on social context or historical period. By “inevitable” I mean phenomena which are subject to natural laws which are universal and unchanging. I can also defend P1 by arguing the distinction between facts and values. Natural phenomena are facts that exist beyond human values. Anything that is subject to human values or norms would be socially mediated, which would include gender.

Now that I have successfully defended P1, to defend P2 one easy example is that of color. It has been argued that men and women prefer different colors due to our hunter-gatherer ancestry (Hulbert and Ling, 2007). Pink used to be seen as a color for boys while blue used to be seen as a color for girls. (See here and here.) The conclusion then follows, since the premises are true and the argument is valid.

Men and women and IQ

Lastly I will discuss the preceding arguments in the context of IQ. For example, Lynn (1994) argues that there is a 4 point difference between men and women in IQ, and relates it to selection pressures. Kanazawa (2009) argues that men have higher IQ than women since men are taller than women, and when height is controlled, women have higher IQ. Irving and Lynn (2006) and Lynn and Kanazawa (2011) also note a small difference between the sexes. But Halpern and Wai (2019) rightly note the historical reasons why there is such a small—almost nonexistent—difference in IQ between men and women:

Massive amounts of data show that although there are some on average differences in specific cognitive abilities, there is considerable overlap in the male and female distributions. There are no sex differences in general intelligence – standardized IQ tests were written to show no differences, and separate assessments that were not written with this criterion show no differences in general intelligence.

When creating his Stanford-Binet test, Terman thought that men and women should be equal in IQ, and so he adjusted his test to reflect this (a priori) assumption. Ackerman (2018) describes this well:

There is an important historical reason why there are negligible gender differences in omnibus IQ assessments. … Terman … decided that there was adequate justification for equality of IQ scores across the sexes, and so he constructed his IQ test to be specifically balanced.

We don’t need to use differences in height, or stories about evolutionary selection pressures, or differences in brain size to explain the small difference between and women on IQ tests. We only need to look at how the tests are constructed, as the considerations from Terman and also Rosser (1989) show. Thus, we don’t need to look to biology and brains to explain the small difference. It is due to how the tests are constructed.


Taken together, the three sections here point to one conclusion: The nonexistence of male and female brains means that gender doesn’t reduce to biology (the brain), nor do brain differences cause IQ differences between men and women. While hereditarians do argue that the brain size differences between men and women “explain” the slight 4 point or so difference in IQ between men and women, and while women do have about an 11 percent smaller brain than men on average, this does not (1) license the claim that brain size is causal for the small IQ differences and (2) justify the claim that there are two distinct kinds of brain (male and female). So claims from people like Murray (2020) that there are two kinds of distinct brain fail. When does a feature count as “typical” of the so-called male or female brain and how many of these features would one of these brains need to have to be designated as male or female? Brains aren’t gendered or sexed, people are, and people aren’t their brains.

P1: If male and female brains don’t exist, then any observed differences in cognitive ability between men and women are likely to be explained by cultural and social factors along with how the tests are constructed.
P2: Male and female brains do not exist.
C: Thus, any observed differences in cognitive ability between men and women are likely to be explained by cultural and social factors along with how the tests are constructed.

Brains are not sexed or gendered, humans (and their selves) are sexed or gendered. While gender identity does exist, it’s irreducible to biology and it is a form of personal identity. As I stated at the outset, the claim that there are male or female brains or that brains are sexed is a mereological fallacy since those are properties of the whole (human) rather than their parts (the brain). These arguments also have implications for claims that transgendered people have brains of “the other sex.” For if two types of brains do not exist, then those claims are false. “Brain sex”, therefore, is a nonsense, incoherent term. Human brains are monomorphic, not dimorphic.

Contra Hereditarians, Temperature is not Like IQ, nor are Thermometers like IQ Tests

2550 words

The invention of the thermometer made it possible to objectify the attribute of temperature, to quantify it, and to measure it with a high degree of reliability. With some important qualifications, the situation is similar in the case of intelligence tests. … To object to this procedure by arguing that the IQ cannot be regarded as being interchangeable with intelligence, or that intelligence cannot really be measured, or that IQ is not the same as intelligence, is to get bogged down in semantic morass. It is equivalent to arguing that a column of mercury in a glass tube cannot be regarded as synonymous with temperature, or that temperature cannot really be measured with a thermometer. – Jensen, 1973: 343, 345; Can we and should we study race differences?

In assessing the methodological role of IQ tests in each of the research programmes, thermometers provide an instructive analogy, for the relationship of thermometers to thermodynamics is rather similar to that of IQ tests to theories of intelligence. (Urbach, 1974: 104)

‘if the measurement of temperature is scientific (and who would doubt that it is?) then so is that of intelligence.’ (Eysenck, quoted in Nash, 1990: 131)

If psychology can’t be measured then that is a huge barrier in the way of psychology actually becoming a science like all of the other sciences it tried to mimic. Psychology has been trying to become a legitimate science for years now. There is of course the so-called replication crisis in psychology (Baker, 2016; Oberauer and Lewandowsky, 2019), but psychologists say that this doesn’t extend to “intelligence”. However, I have argued that psychologists are mistaken. If psychological traits exist (and they do), and if they are a product of immaterial minds (they are), then how could they be measured by empirical methods? That’s the troubling issue for psychology—if psychometrics isn’t measurement (Uher, 2021), and if psychological traits aren’t quantitative (Michell, 1997) and if psychological phenomena aren’t manipulable nor controllable (Trendler, 2009), then how can psychology be an empirical science (Smedslund, 2016)?

Why the Berka-Nash measurement objection matters and what it means for temperature and IQ

This objection is simple—something can be said to be measurable if and only if there is a specified measured object, object of measurement and measurement unit (Berka, 1983; Nash 1990). Where a specified measured object is the thing or phenomenon to be measured, an object of measurement refers to the property that is measured, and the measurement unit refers to a standardized unit which is used to quantify the specified measured object. Since there are, by admission of psychologists, no measurement units in psychology (specifically for IQ, as admitted by Haier (2014, 2018) then it seems that a science of psychology—a science of the mind—is impossible.

In the past, IQ-ists have claimed that their discipline is a science and if temperature can be measured, why can’t intelligence? Nash (1990: 131) puts this succinctly:

First, the idea that the temperature scale is an interval scale is a myth and, second, a scale zero can be established for an intelligence scale by the same method of extrapolation used in defining absolute zero temperature. In this manner Eysenck (p. 16) concludes, ‘if the measurement of temperature is scientific (and who would doubt that it is?) then so is that of intelligence.’ It should hardly be necessary to point out that all of this is special pleading of the most unabashed sort. In order to measure temperature three requirements are necessary: (i) a scale, (ii) some thermometric property of an object and, (iii) fixed points of reference. Zero temperature is defined theoretically and successive interval points are fixed by the physical properties of material objects. As Byerly (p. 379) notes, that ‘the length of a column of mercury is a thermometric property presupposes a lawful relationship between the order of length and the temperature order under certain conditions.’ It is precisely this lawful relationship which does not exist between the normative IQ scale and any property of intelligence.

Basically, what is the property that IQ tests measure? The answer to the question, it seems, is elusive. Contrary to popular belief of IQ-ists, they do not have any refuge by attempting an argument from analogy on IQ tests and thermometers. IQ tests measure intelligence, says the IQ-ist, just like thermometers measure temperature. However, there is no property measured by IQ tests while the property measured by thermometers is thermal expansion—which is a physical property. Thus, contra Eysenck and Jensen, their attempted analogy fails. The construct of temperature was validated in a non-circular manner independent of the original measurement tool used to measure it (see Chang, 2007). The same cannot be same for IQ.

In a wonderful discussion about the measurement of temperature and how it is nothing at all like “intelligence” (and by identity, how the thermometer is nothing like the IQ test), Evans and Waites (1981: 181) write in their book IQ and Mental Testing: An Unnatural Science and its Social History:

The comparison between IQ test development and thermometer development would be appropriate if the history of thermometers had been quite different from what actually took place. Suppose that it was as follows. A crude thermometer was devised. Further thermometers were then invented, and accepted as satisfactory provided that they yielded results which correlated reasonably well with those obtained from the original device. Research into the relationship between heat and other things produced roughly similar results when different thermometers were used, and when this was not the case, a variety of ad hoc explanations were put forward to account for this. It was not considered necessary to investigate the anomalies further because the rough similarities were considered to be much more significant than the anomalies. In this hypothetical case, we have a very good analogy with the development of IQ tests and with research into such topics as the heritability of IQ, and the relationship between IQ and educational achievement. The reason why there is such a sharp contrast between IQ psychology and what actually took place in the theory of heat and thermometer development follows from our discussion of contemporary psychobiology in Chapter 4. It proved extremely productive to conceive of heat as a unidimensional measurable quantity; it is not productive to conceive of human intelligence in this way.

IQ-ists have claimed for decades that IQ (“intelligence”) is basically identical to temperature. Going back to Nash above, there was a scale, a thermometric property of an object, and a fixed point of reference, along with a lawful relationship between the length of mercury in a thermometer and the temperature, say, outside. There is a theory that is used to validate temperature and thermometers and there is no such sinilar theory for IQ and it’s relation to “intelligence”; there is no validating theory for it like there is for temperature.

The kinetic theory of gases validates temperature and thermometers. The length of a column of mercury increases or decreases due to the surrounding temperature of the environment that the thermometer is in. As the mercury in the thermometer is heated (meaning, when the temperature in the environment increases), this results in an increase of the kinetic energy of the mercury particles. So as this kinetic energy increases, the mercury particles move faster and faster while colliding with each other which then causes the mercury in the thermometer to increase. Meanwhile, as the temperature in the environment deceases, the average kinetic energy of the molecules decreases which then causes the mercury to contract and subsequently decrease in the thermometer. This relationship is quite clearly lawlike and a physical relationship.

The arguments

Now here are a few more arguments that psychology can’t be measured.

P1: Scientific measurement requires a consistent and standardized way of observing or quantifying an object or phenomenon.
P2: Psychological traits cannot be observed or quantified in a consistent or standardized way.
C: So psychological traits cannot be measured scientifically.

P1: If psychological traits are a meaningful object of scientific measurement, then they must be observable or measurable in a consistent and standardized way.
P2: Psychological traits cannot be observed or quantified in a consistent and standardized way.
C: So psychological traits aren’t a meaningful object of scientific investigation.

P1: If X is a specified measured object, or phenomenon, then X can be measured using a standardized measurement unit.
P2: Psychological traits cannot be measured using a standardized measurement unit.
C: So psychological traits aren’t a specified measured object or phenomenon. 

P1: If temperature and IQ were similar, then there would be a theory of cognitive processes similar to the kinetic theory of gases.
P2: There is no theory of cognitive processes similar to the kinetic theory of gases.
C: Thus, temperature and IQ are not similar (MT, P1, P2)
P3: There was a theory of temperature developed in the past.
P4: There was no theory of cognitive processes developed in the past.
C2: So temperature and IQ are not similar and there is no theory of cognitive processes similar to the kinetic theory of gases. (MT, C1, P3, P4)

P1 sets up the conditional relationship between IQ and temperature being similar, and a theory of cognitive processes. P2 states that there is no theory of cognitive processes that is akin to the kinetic theory of gases. The conclusion then follows that IQ and temperature are not similar. P3 and P4 are then deployed to show that while there was a theory developed to account for and explain temperature, there was no such theory for human intelligence (“IQ”) , per Ian Deary: “There is no such thing as a theory of human intelligence differences—not in the way that grown-up sciences like physics or chemistry have theories” (quoted in Richardson, 2012).

So it is therefore false, contra the protestations from Jensen, Eysenck, and Urbach, that IQ is similar to temperature, since temperature is a physical property. If you ask any IQ-ist “What property is being measured by IQ tests?”, they won’t be able to provide a satisfactory answer. That’s because there is no theory behind what the tests are “measuring”. Temperature is a fundamental aspect of the physical world. It is a physical property. Since science only deals with physical properties and phenomena, then it can deal with temperature. Since psychological traits are immaterial, they are therefore immeasurable since they lack a specified measured object, object of measurement and measurement unit.

P1: If temperature and IQ were similar, then they would share similar properties and characteristics.
P2: Temperature is a physical property that can be measured using various devices.
P3: IQ is a psychological construct, and can’t be measured using physical instruments.
C: So temperature and IQ do not share similar properties and characteristics.

P1 is based on the idea that if temperature and IQ were similar as had been asserted for years by hereditarians, then they would have theories explaining then along with the underlying mechanisms for them. This has occurred for temperature, but not for IQ. So the premise suggests that temperature and IQ are not similar. P2 is based on the idea that there is a well-established theory of temperature, but not IQ (see Richardson and Norgate, 2015 for examples of real, valid measures of unseen functions and mechanistic relations between variables). There is no overarching theory of IQ that can explain all aspects of it in the same way that the kinetic theory of gases explains temperature. P3 and P4 are based on historic facts: as alluded to above, the kinetic theory of temperature explains the behavior of molecules which then explains the expansion of mercury in a thermometer (it explains the expansion and contraction of materials and temperature); while there is no single theory that can be considered to be such an explanation for IQ. Therefore, temperature and IQ are not similar, and attempts to treat them as similar are unwarranted.

Now here is the master argument, which I call the physical properties and theories argument, which establishes that temperature is measurable since it is a physical property with an established theory while the same isn’t true for IQ.

P1: Physical quantities are measurable.
P2: Temperature is a physical quantity.
C: Thus, temperature is measurable. (MP, P1, P2).
P3: Psychometric intelligence (“IQ”) is a hypothetical construct.
P4: Hypothetical constructs are unobservable.
P5: If something is unobservable, then it is immeasurable and so it cannot be quantified.
C2: Psychometric intelligence is unobservable and so it is immeasurable thus it can’t be quantified (MT, P1, P3, P4, P5).
P6: The validity of a measurement is based on a well-established theory.
P7: There is a well-established theory of temperature.
C3: Therefore, measurements of temperature are valid. (MP, P6, P7)
P8: There is no well-established theory of cognitive processes.
P9: Psychometric intelligence is (supposedly) a measure of cognitive processes.
C4: Thus, measurements of psychometric intelligence lack validity. (HS, P6, P7, P8,P9)


As can be seen, even if we accept claims from IQ-ists (and we definitely don’t have to), then what they try to argue for still fails. Over the decades, quite a few authors have attempted an argument by analogy—that if the measurement of temperature was a valid scientific method, then so was the measurement of intelligence using IQ tests. However I have provided a few (more) arguments for the claim that IQ is nothing like temperature since temperature is a physical property and psychological traits (IQ) have no theory so they therefore cannot be measurable (along with numerous other arguments). The fact of the matter is, contra Jensen, Eysenck and Urbach, thermometers and temperature are not related—that is, they are not identical with—IQ tests and IQ/intelligence, since one is physical and based on actual physical measurements with a theory and a specified measured object, object of measurement and measurement unit. The same, obviously, cannot be said for IQ. Thus, the claims put forth by Jensen, Eysenck and Urbach fail. Measurement by fiat—like “intelligence”—aren’t theoretically justified (Berka, 1983: 131). I have, yet again, shown that IQ is not a physical measurement, and so, IQ isn’t a physical property, and that there is no specified measured object, object of measurement and measurement unit for IQ. Therefore, temperature is NOT to IQ like thermometers are NOT to IQ tests.

The scale for temperature measurement was originally defined by stipulation with regard to the mercury thermometer. In this case, the notion of temperature can be interpreted only for materials within the range of their values between the point of thawing and the boiling point of mercury. Since an empirical law exists, according to which one may view temperature (under a constant pressure) in this range as a function of volume, we can measure the temperature of materials indirectly, on the ground of laws, by means of a gas thermometer, i.e., by virtue of establishing the volume which will be occupied by a definite standard amount of gas (under the specified pressure) in contact with the measured material. Should we now use a derived measurement by stipulation, we might decide that temperature will also exist outside the range of the original measurement of the functions of volume. Within the framework of measuring temperature by means of a mercury thermometer, the use of a gas thermometer represents a derived measurement on the basis of laws, while outside this framework it represents a derived measurement by means of stipulation. (Berka, 1983: 130)

Gender Identity is Personal Identity

1500 words

It has been common in recent years to claim that gender identity (GI) doesn’t exist. For example, one religious argument that GI doesn’t exist is that since God made only men and women, then we should not “overrule the work of God.” However, to claim that GI doesn’t exist is patently ridiculous. It’s ridiculous since GI is merely a subset of personal identity (PI). PI exists, so GI exists too, since GI is a subset of PI. I will provide an argument for the claim that GI is PI and if GI is PI, then GI exists.

The origins of the nature-versus-nurture debate

In his book Genes, Determinism, and God, Denis Alexander cited what may be the first instance of the nature versus nurture dichotomy. A 13th century novel called Silence was discovered in 1911, and in it is perhaps the first discussion of nature versus nurture. In the story, the kind of England married the daughter of the king of Norway which the ended a long war they were in. The king of England then passed a law stating that family inheritances cannot be passed on to women. After passing this law, the king was rescued by a knight from a dragon. So the king offered the knight an estate and a lady of his choosing, who turned out to be the king’s nurse. They then got married and then had a daughter who was unable to inherit their money due to the law the king previously passed. So the knight and the nurse named their child Silentius, and then tasked two of their servants to raise the child as a boy.

Alexander then quotes the book in which nature, nurture, and reason are personified and then duel over the ultimate identity of Slientius. Nature states that Silentius is a girl, and that she should return to her appropriate gender role. Nurture and reason then convince Silentius that it would be better go continue being a boy, since they could be put to death if her identity was discovered.

Alexander (2074: 39) quotes what Nature and Nurture said to Silentius in the novel:

This is a fine state of affairs,
You conducting yourself like a man,
running about in the wind and scorching sun
when I used a special mold for you,
When I created you with my own hands,
When I heaped all the beauty I had stored up upon you alone! (2502-9)

But nurture will have none of it:

Nature, leave my nursing alone,
or I will put a curse on you!
I have completely dis-natured her. (2593-5)

Silentius is then brought to the king’s court, where the queen falls in love with Silentius since she sees Silentius as a man. The queen then eventually grows to hare Silentius and tries to have Silentius killed. So the queen sends Silentius to try to capture Merlin, since it is said that he could not be captured since he acted like a beast. Silentius then cooked him some meat and gave him some wine and captured him. So Nurture influenced Merlin to become like a beast and not eat cooked food, so when Silentius gave Merlin cooked food, Merlin then gave into his nature and rejected the nurturing of himself as a beast. Now that Nature had won out with Merlin, now it was Silentius’ turn to have nature win out with them.

With Nature’s final triumph, the time is ripe for unmasking Silence. On his way to Eban’s palace, Merlin laughs at various people for no apparent reason. Attacked by people as a false prophet and pressed by King Eban, Merlin is forced to reveal the reasons behind his laugh: he laughs at a group of lepers begging for alms because they are standing on buried treasures; at a man burying his child with a priest by his side because the child is in fact the priest’s. Finally, he laughs at a nun in the Queen’s entourage because that nun is only a woman in clothing, just as Silence is only dressed up as male. The ‘nun’ turns out to be the Queen’s lover in disguise, while, marvelled by all, Silence reveals why ‘she’ becomes ‘he’. The romance ends with a classic happy ending: the Queen is punished by death, and Silence, now changing her name to Silentia, becomes the new queen. (The Boy Who Was a Girl: The Romance of Silence)

So Nature won out from Nurture two times in this story, once regarding Silentius and then again regarding Merlin. So, contrary to popular belief that Francis Galton was the one to pit nature and nurture against each other, (one of) the earliest instances of the dueling aspects of Nature and Nurture was from that 13th century French novel. Obviously, Silentius’ GI was that of a man since that is how they were raised. But then, ultimately, Nature won out and Silentius went back to living as a women.

Now, this is just a story and of course nature vs nurture is a false dichotomy, but it is interesting to note the earliest instances of the nature-nurture debate. In any case, it’s also a good illustration of how GI is PI.

The argument that gender identity is personal identity

The argument is simple—PI is the unique numerical identity identity of a person over time. On a bodily account of PI, persons are identical to their bodies. On the brain account, we are identical to our brains. We are not identical to our bodies (Lowe’s 2010 argument), nor are we identical to our brains (Gabriel’s 2017 argument). So I am not my body nor am I my brain. So what am I? I am an immaterial self (Lund’s 2005 argument) and I am not reducible to the brain or nervous system (aspects that are studiable by science) (Hasker’s 2010 argument). So I hold to the simple view of personal identity.

Noonan (2019a: 27-28; also see Noonan, 2019b) writes:

Persistence of body and brain or psychological continuity and connectedness are criteria of personal identity only in the sense of evidence: they are not what personal identity consists in. Indeed, there is nothing (else) that personal identity consists in: personal identity is an ultimate unanalysable fact, distinct from everything observable or experienceable that might be evidence for it. Persons are separately existing entities, distinct from their brains, bodies and experiences. On the best-known version of this view, a person is a purely mental entity: a Cartesian pure ego, or spiritual substance. This is in fact the form in which the view is adopted by its contemporary defenders, among whom the most prominent are Chisholm and Swinburne. Following Parfit, I shall call this the simple view.

Mental entities are “private, non-material objects” (Sussman, 1975) so persons are purely mental entities which are not reducible nor identical to brains or bodies. GI is one’s personal conception of self and GI is a subset of PI. So if PI exists, then so does GI. Now here is the argument that gender identity is a form of personal identity.

P1: PI refers to the unique characteristics and qualities that define an individual as a distinct entity.
P2: GI is a core aspect of one’s self-concept and self-expression which deeply influences their personal experiences and relationships.
P3: If an aspect of a person’s self-concept and self-expression deeply influences their personal experiences and relationships, then it is a key component of their PI.
C: Thus, GI is a form of PI.


P1: If PI is the set of characteristics that define an individual, then GI is a form of PI.
P2: If GI is a fundamental aspect of a person’s self-concept and self-expression, then GI is a form of PI.
P3: GI is a fundamental aspect of a person’s self-concept and self-expression.
C: So GI is a form of PI.

Both of these arguments are valid and sound, therefore GI is a form of PI. So if PI exists then it follows that GI exists. So claims to the contrary that GI doesn’t exist are therefore false.


I have shown that GI exists and I have successfully argued that it is a form of PI. This then refutes claims that GI doesn’t exist. I discussed one of the first instances of the nature versus nurture dichotomy from a 13th century French novel called Silence, where Nature, Nurture, and Reason are personified, in an attempt to get people to go with their “natures” over their nurtures. In the story, Nature eventually wins out. Though in real life, this doesn’t work out due to the interaction between nature and nurture, genes and environment. So this instance is one of the first instances of the debate, which predates Galton by almost 500 years.

I then discussed what PI is and of course rejected the brain, body and physical views of PI. This is because we are partly immaterial, that is, the self is an immaterial substance or mental entities. I then, finally, presented two arguments that GI is a form of PI. PI clearly exists, so if PI exists then GI exists. It’s that simple.

A Critical Analysis of Kershnar’s Argument in Moral Value and Racial Differences

1800 words

In the year 2000, philosopher Stephen Kershnar published a paper titled Intrinsic Moral Value and Racial Differences (Kershnar, 2000). In the article, he argues that whites and Asians have greater per capita moral value than blacks, since ceteris paribus, autonomy is proportional to intelligence and moral value is proportional to intelligence. In this article, I will show how Kershnar’s argument is flawed.

Kershnar’s argument

(P1) Other things equal, intrinsic moral value is proportional to autonomy.
(P2) Other things equal, autonomy is proportional to intelligence.
(C1) Hence, other things equal, intrinsic moral value is proportional to intelligence. [(PI), (P2)]
(P3) Whites and Asians have greater per capita levels of intelligence than blacks.
(C2) Hence, other things equal, whites and Asians have greater per capita intrinsic moral value than blacks. [(Cl), (P3)]
(P4) Other factors do not offset this difference in per capita moral value.
(C3) Hence, all things considered, whites and Asians have greater per capita intrinsic moral value than blacks. [(C2), (P4)]

The inference in C1 is transitive property of equality where if A = B and B = C then A = C. Intrinsic moral value is proportional to autonomy (A = B) (P1), while autonomy is proportional to intelligence (B = C) (P2), so intrinsic moral value (A) is proportional to intelligence (C), so A = C justifying the inference. It also uses a form of proportional reasoning to show the A = C (intrinsic moral value = intelligence). P3 and C1 are then used to derive C2 through deduction. He then assumes the truth of P4, which then establishes C3, which states that, ceteris paribus, whites and Asians have greater per capita moral value than blacks, so C2 and P4 are used to derive the conclusion in C3.

Critical discussion of Kershnar’s argument is scant, being that over the 23 years since the paper was published, there are a mere 7 citations of the paper, 3 of which are from Kershnar himself. The implication of the argument is that the United States should deprioritze aid to Africa, since rendering aid there would be useless based on their average “intelligence.” He, of course, relies on IQ differences between blacks, whites, and Asians as grounds for his argument here. He brings up the myth of “general intelligence”. In any case, he states that differences in IQ being due to genetic or environmental factors doesn’t matter—since lowered IQ due to environmental factors result in “a lowered level of intelligence that results from environmental deprivation correlates with less autonomy, other things equal, every bit as much as a lowered level of intelligence that results from genetic factors” (Kershnar, 2000: 217). This claim, of course, is nonsense, as IQ isn’t a measure at all, nevermind a measure of “general intelligence.” Thus, C1 and P3 can be rejected, which would mean that, also, C2 then doesn’t follow.

Kershnar’s argument is basically saying that whites and Asians have more inherent value or worth than whites and Asians. Conclusion C2 which is derived from P3 is false and if is further based on a misunderstanding between the nature of IQ scores and so-called “intelligence.” Nevermind the fact that Asians are a selected population. Now I will discuss each premise.

Premise 1: This premise claims that intrinsic moral value (IVM) is proportional to autonomy. It is a reductionist view, which equates morality with autonomy. Numerous other factors also contribute to autonomy, and autonomy and moral value cannot be reduced to a single number. Nevermind the fact that IVM and autonomy aren’t measurable variables.

Premise 2: Like P1, P2 also assumes a reductionist view of of autonomy which equates it with “intelligence.” I don’t doubt that cognitive ability is related to autonomy, however, Kershnar’s claim that autonomy is proportional to intelligence is outright false, and so P2 must be rejected.

Conclusion 1: Even IF P1 and P2 are accepted (and I see no reason why we should accept them), it does not follow that IMV is proportional to “intelligence.” Many other factors contribute to IMV than merely “intelligence.” Thus, P2 and C1 are not entirely true.

Premise 3: This claim is just straight-up false. There is no reason to claim that differences in IQ scores are differences in “intelligence.” While Kershnar does assume that IQ is a measure of g, and also tries to argue that even if the observed IQ differences are due to either genetic or environmental factors that it doesn’t hurt his overall argument, it actually does. Due to what we know about the nature of IQ test construction and the ability to build in or out what the test constructors desire, we therefore cannot and should not accept the claim in premise 3. Furthermore, there are philosophical arguments (Spencer, 2014; Hardimon, 2017) that while race exists and is a social construct of a biological reality, we cannot be justified in claiming that, over and above physical differences, genes contribute to socially-desired/-valued traits. Even if there were differences in “intelligence” between races, this would not justify the claim that differences in Intelligence and autonomy translate to IMV. The rejection of P3 makes his argument crumble.

Conclusion 2: This conclusion is outright racist. It is racist since it assumes that intelligence is directly related to moral worth. The claim that certain racial groups have more intrinsic value than others has been, in the past, used to justify morally repugnant actions such as Jim Crow, slavery and segregation. C2 isn’t false because it’s racist—that’s merely a descriptive claim about C2—but it is false since it is based on false premises (C1 and P3). So C2 must be rejected.

Premise 4: This premise is straight up ridiculous. It is false because it assumes that other factors don’t off-set IMV. IMV is influenced not only by individual characteristics or traits, but also by social and cultural contexts and factors such as education and upbringing.

Conclusion 3: C3 is derived from C2 and P4. As already discussed, C2 is outright racist but it being racist isn’t why it’s false, it’s false since it is based on false premises. P4, again assumes that no other factors influence per capita IMV.

Refuting Kershnar’s argument

Now that I have analyzed Kershnar’s premises, I will now provide an argument against Kershnar’s argument.

P1: Autonomy isn’t solely determined by cognitive ability.
P2: IMV isn’t solely determined by cognitive ability or autonomy.
P3: The claim that whites and Asians have greater per capita intrinsic moral value than blacks based on differenced in cognitive ability is unfounded and outright discriniminatory.
C: Thus, the argument that whites and Asians have a greater per capita IMV than blacks is invalid and so Kershnar’s argument isn’t sound.

P1 states that autonomy isn’t solely determined by cognitive ability. There are many other factors that determine autonomy, like socio-environmental factors which are independent of cognitive ability. P2 asserts that other factors contribute to an organism’s moral value. The idea that cognitive ability is related to one’s moral value has been used in the past to justify discriminatory policies and forced sterilization of people found to be “low IQ.” This is one reason why IQ tests should be banned, since they have been used to justify discriminatory policies and sterilization in the past. Further, infants, children, people with cognitive disabilities and animals are considered to have moral value, even though they don’t have the same cognitive capacities as adult humans. P3 claims that Kershnar’s overall claim that whites and Asians have greater per capita IMV than blacks is unfounded, along with the fact that it is outright discriniminatory. Here is an argument for P3:

P1: If claims of IMV based solely on differences in cognitive ability are justified, then discriniminatory beliefs and practices are also justified.
P2: Discriniminatory beliefs and practices are not justified.
C: So claims of IMV based solely on cognitive ability aren’t justified.

Thus, the conclusion of the original argument against Kershnar’s argument follows—like in my argument to ban IQ tests, if we belief the hereditarian hypothesis is true and it is false, then it will lead to certain discriniminatory policies and beliefs. Since Kershnar’s argument is, basically, an argument using hereditarianism for our moral values, then this, too, is another reason why IQ tests should be banned. Nevertheless, Kershnar’s argument isn’t sound and it is refuted.


An implication of Kershnar’s argument is that we should not give aid to African countries (I argue that we should) and that, if we saved Europeans and Africans, that it would be more morally praiseworthy to have saved Europeans over Africans (Engelbert, 2015). Engelbert’s (2015: 186) note 16 also talks about the “repugnancy” and “absurdity” of Kershnar’s argument.

On the absurdity point: Kershnar’s argument that more intelligent beings possess greater autonomous agency is based almost entirely upon thought experiments involving comparisons between humans and non-human animals, or between humans with normal cognitive abilities and those with serious disorders that inhibit mental functioning. Thus, the notion of “intelligence” he utilizes bears little resemblance to the use of the term in psychometrics (from which he draws his claim that racial groups differ in “intelligence”). Kershnar provides no reason for thinking that autonomy, understood in the way moral philosophy uses the term, is proportional to intelligence in the psychometric sense. On the repugnancy point, it’s also worth noting that Kershnar’s extrapolation of comparisons between “human beings and pigs” (2000, p. 222) to comparisons between Whites and Blacks is full of troubling implications.

Nevertheless, Kershnar’s argument is outright racist, but that doesn’t mean that it’s false. I have outlined the reasons why it’s false, his assumptions are hardly argued for (like the claim that autonomy is proportional to “intelligence”), and so, Kershnar’s argument must be rejected. I also have provided a counterargument against Kershnar’s, which thusly invalidates it. Now here is one final argument against Kershnar’s:

P1: All human beings have inherent moral value and worth regardless of their cognitive ability and race.
P2: Autonomy is a fundamental principle of moral value.
P3: Autonomy isn’t solely determined by cognitive ability but also by factors like cultural background, personal experience, and social context.
C: Thus, it is morally wrong to claim that whites and Asians have greater IMV than blacks based solely on cognitive ability, since it violates the principle of non-discrimination.

At the end of the day, Kershnar’s argument seems to be deployed in order to deny aid to African countries. However, giving aid to African countries will decrease their birthrate, as empirically shown in other countries. C3 in Kershnar’s argument is both scientifically and morally flawed. For reason—among the others laid out above—Kershnar’s argument is unsound and must be rejected. Kershnar’s argument applies hereditarian “science” to moral worth of racial groups, which is another reason why the argument doesn’t work, since hereditarianism isn’t a valid science.

An Argument for the Existence of Mind and Intentional Consciousness

2100 words

Consciousness and mind are uniquely human attributes. They allow us to reason and act intentionally. But what establishes the claim that consciousness and mind exist if they are immaterial? I have a few arguments for the claim, and I will also add a semi-updated version of the argument I made against animal mentality. So I will combine the argument that humans possess a mind (that is, that the mind is real and has referents) with the argument that nonhuman animals lack propositional attitudes and so they lack language and intentional states, and so they lack minds like humans. So the conclusion will be guaranteed—minds exist and only humans are in possession of them. First I will provide the argument that the mind exists since the existence of consciousness implies the existence of a nonphysical entity. After defending the premises, I will then shift to the argument that the problem of mental causation isn’t a problem for dualism. Then I will argue that only humans have minds and, due to the nature of intentionality and normativity of psychological traits, nonhuman animals lack minds like humans since they lack the prerequisites that entail having a mind.

An argument for the existence of mind

P1: Consciousness is a real, undeniable phenomenon that cannot be fully explained by physical or material processes.
P2: If consciousness cannot be fully explained by physical or material processes, then it must be a nonphysical phenomenon.
C1: Thus consciousness is a nonphysical phenomenon.
P3: The existence of a nonphysical phenomenon requires the existence of a nonphysical entity that can support or generate such phenomena.
C2: So the existence of consciousness implies the existence of a nonphysical entity.
C3: This nonphysical entity is the mind, so the mind exists.

Call this the argument from consciousness. Consciousness is a subjective, first-personal experience that everyone has and which cannot be reduced to physical or material processes. It is an experiential fact that each and every one of us is aware of their experiences and their thoughts, feelings, and perceptions; these cannot be explained by material or physical brain processes, due to the explanatory gap argument.

Premise 1: Of course we can study NCCs (neural correlates of consciousness), and this is what neuroscience does, but that’s not the same as studying the mind. The actualization of mind is not the same as that of digestion; gastroenterologists can study the physiological process of digestion, but neuroscientists can’t study the mind, since the mind isn’t merely brain physiology or brain/CNS (central nervous system activity) activity.

Premise 2: We can study material and physical processes, like brain states/physiology/CNS, using scientific inquiry. But if consciousness cannot be fully explained by physical or material processes, then it must be explained by the existence of a nonphysical entity and this also suggests that consciousness is an irreducible, nonphysical phenomenon.

Conclusion 1 then logically follows from P1 and P2.

Premise 3: Like P2, if consciousness is a nonphysical phenomenon, then it must be explained by a nonphysical entity since physical accounts cannot fully account for consciousness.

Conclusion 2 then logically follows from P3 and P4, and then conclusion 3 then follows from C2. So the argument is established on the grounds that consciousness exists and cannot be explained by material or physical processes, and if something exists which cannot be explained by physical or material processes then this implies the existence of a nonphysical entity that can support or generate such consciousness, and this nonphysical entity is referred to as MIND.

The limitations of material and physical explanations entail that the mind isn’t a physical process or a function of physical processes. The Knowledge Argument concludes that everything can’t be explained by physical or material processes, which would then strengthen the overall argument for the existence of an immaterial substance that explains consciousness. So there is a knowledge gap between physical explanations and subjective, individual explanations, and this is what the Knowledge Argument gets at. (Morch’s explanatory knowledge argument against physicalism establishes that some facts are nonphysical, which establishes the existence MIND.)

If the mind is immaterial, then how does it interact with the physical brain?

This question has been said to be a knockdown argument against dualism. If M and P are two different substances, how can they be said to interact? How, then, can the mind cause things to happen in the physical world? This is known as the problem of mental causation. How can mental events have any causal efficacy on physical events?we then need to establish between event causation and intentional causation (Lowe, 2001, 2009).

Intentional causation is mental causation (fact causation), and bodily causation is physical causation. Mental causation doesn’t reduce to physical causation, and this is because mental causation is intentional whereas physical causation isn’t. We have voluntary control over our actions, and so, we can intend to do things. So in Lowe’s (2006, 2010, 2012) non-Cartesian substance dualism (NCSD), persons or selves are distinct from their physical bodies and parts of their physical bodies. NCSD can better explain mental causation than the alternative materialist/physicalist theories, and so it can’t explain the intentionality of mental causation. The self is not the body, mental states aren’t physical states/processes (nor are they reducible to physical states/processes). The intentional content of mental states explains their uniqueness in contrast to physical states and event causation (Lowe, 1999).

P1: If M events cause P events, then mental causation isn’t a problem for dualism.
P2: Mental events do cause physical events.
C: So mental causation isn’t a problem for dualism.

So this is based on Lowe’s distinction between event and agential causation. Agential causation means that an agent can cause events that mere physical event causation cannot and agential causation cannot be reduce to event causation. Agents aren’t events nor are they processes, al they are entities with powers that can enact causal chains. So mental events which are caused by agents can cause physical events sans violating any laws of nature, and this doesn’t require that mental events are identical to or reducible to physical events. Thus if mental events can cause physical events—which we have experiential and empirical evidence that they do—then the problem of mental causation does not pose a problem for dualism.

Premise 2 now needs defense. Mental events like thoughts, beliefs and desires can cause bodily movements. If you desire to go to the store and buy something, then your desires are directing your actions; the mental intention to move the body is then carried out. Also, experiencing pain (a mental event) can cause a reaction, which would then cause the avoidance of the source of the pain. Furthermore, we also deliberate on what to do, while considering different outcomes and options and then act based on our mental states at the time. Lastly, if mental events did not cause physical events, then we wouldn’t be able to hold people responsible for their intentional actions. So P2 is true and the conclusion then follows that mental causation isn’t a problem for dualism.

Then we have Krodel’s (2013) counterfactual argument for mental causation which can be formed like this:

If the mind were different, then the physical world would have been different, al M events cause P events in the world. Krodel (2013: 3) puts it like this:

My headache caused me to take an aspirin. This claim sounds as natural as any. A dualist too can make it. More importantly, a dualist can provide a rigorous argument for it. Nothing depends on the specifics of headaches and our reactions to them, so let m be some actually occurring mental event and b it’s actually occurring later behavioral effect (‘putative behavioral effect’, if you like, to quell any suspicion of begging the question). The argument has a complicated part with the conclusion that if m had not occurred, then b would not have occurred, and a simple part with the conclusion that m caused b. Let us start with the complicated part:

(1) If none of m’s physical bases had occurred, then b would not have occurred.
(∼∪P → ∼B)

(2) If m had not occurred, then none of m’s physical bases would have occurred.
(∼M → ∼∪P)

(3) If none of m’s physical bases had occurred, then m would not have occurred.
(∼∪P → ∼M)

(4) If m had not occurred, then b would not have occurred.
(∼M → ∼B)

It can also be put like this:

P1: If a mental event didn’t occur, then a physical event wouldn’t have occurred.
P2: If a mental event didn’t occur, then a different physical event would have occurred.
C: So the mental event causally contributed to the physical event.

So mental events make the difference to the counterfactual dependence of the physical events on the mental causes. So the mental event is causally relevant to the instantiation of the physical event, even if the mental event isn’t causally necessary. So again, the problem of mental causation isn’t a problem for dualism.

The argument for the uniqueness of human intentional consciousness

This is going to be a long argument, so bear with me.

P1: Humans are capable of intentional action, which involves the use of reason and purpose to achieve goals.
P2: Intentional action requires a mental capacity to represent and reason about the world.
P3: This mental capacity is what we refer to as MIND.
C1: Thus, humans possess a mind. (modus ponens, P1, P2, P3)
P4: Humans have intentional consciousness which involves being aware of thoughts, beliefs, and desires along with the ability to form and pursue goals.
P5: Intentional consciousness requires the ability to represent and reason about mental states.
P6: The possession of a mind is necessary for intentional consciousness.
C2: So humans have intentional consciousness (modus ponens, P6, C1).
P7: To be able to think, an organism must have a full range of propositional attitudes like beliefs, desires, intentions, and knowledge.
P8: Having a full range of propositional attitudes rests on having language.
P9: Nonhuman animals lack language.
P10: Nonhuman animals lack a full range of propositional attitudes.
P11: Since a full range of propositional attitudes is necessary for thinking, then nonhuman animals can’t think.
C3: So nonhuman animals lack MIND. (modus tollens, P3, P10, P11)
P12: Nonhuman animals have phenomenal consciousness, that is, there is something it is like to be a certain animal.
P13: Phenomenal consciousness does not require the ability to represent and reason about mental states.
P14: Intentional consciousness is a higher level of consciousness that requires both phenomenal consciousness and the ability to reason about and represent mental states.
C4: Therefore, no nonhuman animal possesses intentional consciousness. (modus tollens, C2, P12, P14)

P1-P6 establish that humans possess a mind and intentional consciousness and that nonhuman animals lack intentional consciousness. P7-P11 build on this and introduce the ideas that in order to think, an organism needs to have a full range of propositional attitudes, and since a full range of propositional attitudes rests on having language, and nonhuman animals lack language, then nonhuman animals can’t think which then leads to the conclusion that nonhuman animals lack MIND because thinking is a necessary component of MIND. P12-P14 state the distinction between phenomenal and intentional consciousness, and show that nonhuman animals have phenomenal consciousness but not intentional consciousness. Phenomenal consciousness does not require the ability to represent and reason about mental states, which is necessary for intentional consciousness.

So, minds exist and humans have them, humans have intentional consciousness (since humans can reason to achieve goals), nonhuman animals lack mind (since they lack language and therefore propositional attitudes) and nonhuman animals lack intentional consciousness (since they have phenomenal consciousness and no nonhuman animal can have intentional consciousness).


I have argued that humans have consciousness and that consciousness isn’t reducible to physical or material processes. Consciousness is a nonphysical phenomenon and since it is nonphysical, then only an immaterial, nonphysical thing can support or generate nonphysical consciousness and this immaterial thing is the mind. Mental causation isn’t a problem for dualism, since mental events can and do cause physical events. Krodel’s counterfactual argument for mental causation was provided to help establish the claim. Lastly, I argued that humans are capable of intentional action and so they possess minds, while arguing that humans have intentional consciousness nonhuman animals lack mind and so nonhuman animals lack intentional consciousness. This is due to the fact that nonhuman animals lack language and so they lack propositional attitudes and therefore intentional states.

So the ultimate conclusion here is that humans are special, a part of our constitution is nonphysical and irreducible (MIND), and so nonhuman animals don’t share MIND since they lack language and propositional attitudes, so they lack intentional consciousness.