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P1: Dualism is the belief that the mind is a nonphysical entity that is distinct from the body.

P2: If dualism is true, then the mind cannot be studied by science since science can only study physical processes and phenomena.

C: Thus, since dualism is true, the mind cannot be studied by science. (modus tollens, P1, P2)

P1 defines what dualism is. P2 states that if dualism is true then it cannot be studied by science since science can only study what is physical and it’s processes. So the conclusion follows from P1 and P2 using modus tollens, since dualism is true then the mind cannot be studied by science. Evidence and reasons for each premise will be given in the body of this article.

Introduction

The relationship between the mind and body—termed “the mind-body problem”—has puzzled us for many millennia. Over this time period, many philosophical theories/arguments have been made claiming to solve the problem. From physicalist, to dualist, to eliminativist, to idealist, and everything in between, many arguments have been mounted that claim to have solved the problem. The solution (or lack thereof) to the problem has implications on what we think of the mind and how—if it is indeed possible—to study the mind using the principles of science. In this article, I will review some arguments for physicalism of the mind, some hereditarian thoughts on the mind (since hereditarianism is a form of mind-brain identity theory), and finally, I will argue that if the mind is not a physical object then it cannot be (1) selected for by the environmental filter that “selects for/against” deleterious/advantageous traits and (2) an object of scientific study. Mind is distinct from body, making it outside the realm of scientific explanation. Psychology is said to be the scientific study of the mind, but if what I argue here is true, then there cannot be a science of the mind as the mind is immaterial.

The nature of mind

What is the mind? The mind is, very simply, what allows our mental life—it’s a set of mental faculties which allow our mental life. Concepts of the mind are similar cross-culturally in 5 different cultures and these concepts are present by mid-childhood but there were differences in how the social-emotional concepts were thought of (Weisman et al, 2021). Physicalists claim that since the mind is just the brain, then if we study the brain then we can study the mind—what allows our mental life.

On functionalism about the mind, the mind is what the brain does just like digestion is what the stomach does. That is, digestion is just the result of physical processes that occur when one is hungry and then eats so then the mind is what the brain does and this mental activity arises when the agent sees physical things. However, minds are intentionally constituted, and digestion is not so this analogy fails.

So the implicit claim here is that there can basically be a physiology of the mind on functionalism. Functionalist accounts of the mind suggest that mental particulars could be physical and so by studying the physiological states of the brain, we can then study the mind. Since physiology is a result of the interactions between mental life and what the agent experiences/sees then we can study this process scientifically. But there are problems with the functionalist account of mind.

The two main issues are (1) functionalism can be seen to be a type of mind-brain identity (which is the claim that mental states are merely brain states and so the mind is identical to the brain and its physiological processes; Smart, 2007) and (2) since all formal thinking is determinate and no physical process can be determinate then formal thinking cannot be physical or a result of physical processes, which then refutes functionalism of the mind (Ross, 1992; see also Feser, 2013). The argument can be formulated like this:

1) All formal thinking is incompossibly determinate
2) No physical process or functions of physical processes are incompossibly determinate
∴Thoughts aren’t a physical or functional process; no physical process is formal thinking; therefore functionalism and physicalism are false

The claim that the mind is what the brain does entails that mind reduces to brain and so the brain is the thing that thinks and feels and decides. This, however, is an example of the mereological fallacy (Kitchen, 2015). This kind of conceptual confusion arises when one imputes psychological predicates to the part (in this case the brain) when they actually apply to the whole (the self, “I”, the person). Brains don’t think, humans think. Brains don’t get sad, happy, or angry. Humans do. Brains are needed to think, to be happy, sad or angry. But this does not entail that brains are “feeling” the emotions or thinking. Psychologist Richard Haier has a lecture titled The Intelligent Brain, and this shows that he falls prey to the mereological fallacy. The brain is the thing that allows us to think, this is true. But to IQ-ists like Haier, it is the “quality” of the brain (whatever that would mean) that would dictate IQ scores. (This claim can be evidenced by looking at Haier’s brain imaging studies and attempts to correlate/localize aspects of cognition to fMRI readings and similar technologies along with his 2016 book—The Neuroscience of Intelligence. But we cannot localize parts of the brain to aspects of our cognition using meta-analyses of fMRI and IQ studies, see Uttal, 2012, 2014.) Hereditarians fall into this same conceptual confusion about the relationship to the mind and the brain, which I will review below.

Cognitive scientists, it is said, have been “implicit” dualists; that is, what they write can be construed as having dualist sympathies and that they are guilty of the mereological fallacy (Bennett and Hacker, 2004; Smit and Hacker, 2014; Kitchen, 2015; Boyles and Garrison, 2017). The mind is NOT merely the brain, as many have claimed. And if one does make that claim then they are guilty of the mereological fallacy.

The physicalist argument for mind-brain identity and functionalism is therefore refuted on a priori grounds. Since physical states are indeterminate, that means that there is nothing about a particular physical state that would tell you exactly what it would/could be and it could in fact be many incompossible forms. The argument shows that the mind is non-physical and if it is non-physical then it cannot be studied by physical sciences.

Dualism is true

If dualism is true, then attempts at a science of the mind are impossible. The immateriality of the mind can be proven a priori. Empirical evidence, then, is irrelevant to a priori, conceptual arguments. Conceptual arguments are based on logical coherence and not empirical evidence.

Thomas Nagel (2012), with the publication of his Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False, set off a firestorm with his arguments against Darwinism (as did Fodor and Piattelli-Palmarini, 2009; see Evan, 2014). Nagel argues that the natural and social sciences cannot explain the existence of the mind and so we must revise our conception of nature. Nagel’s (2012: 23) argument is:

But if the mental is not itself merely physical, it cannot be fully explained by physical science. And then, as I shall argue, it is difficult to avoid the conclusion that those aspects of our physical constitution that bring with them the mental cannot fully be explained by physical science either. If evolutionary biology is a physical theory—as it is generally taken to be—then it cannot account for the appearance of consciousness and other phenomena that are not physically reducible. So if mind is a product of biological evolution—if organisms with mental life are not miraculous anomalies but an integral part of nature—then biology cannot be a purely physical science.

Mind is not a product of biological evolution since it is not physical, but if we accept physicalist premises then biology is something more than a physical science. I don’t think many physicalists would accept this. The first argument in this passage is sound and it establishes the fact that what is not physically reducible (consciousness) cannot be explained by science. If science cannot study what is immaterial, then it cannot explain what is immaterial. So science therefore cannot explain the mind. Since (some forms of) materialism requires reductionism and reductionism is false, then materialism cannot explain the mind. The argument has force against, of course, evolutionary psychology as well. Along with being a field full of just-so stories, even if we disregard that, since the object of their “study” isn’t physical, then we cannot explain it using scientific principles and so, natural selection about the mind fails which then refutes neo-Darwinian hereditarian theories of the mind and the evolution of racial differences in mind, as well.

Of course, the physical being a necessary pre-condition for human mindedness matters, but it is not a sufficient condition to explain our mental life (Gabriel, 2017). The claim that the mind can be explained scientifically is, also, basically scientism, which is the claim that we can only derive knowledge from our 5 senses. Some arguments that argue for the physicality of mind state that if brain damage occurs then the mind is, too, affected and this proves that the mind has a physical basis. This, however, is expected on a dualist account as well. Scientists (physiologists) can study physiological states, but since the mind isn’t simply the brain’s physiology—that is, since the mind is not identical to physical or functional states (i.e., the mind is not simply what the brain does just like digestion is what the stomach does)—then since the arguments given above prove the immateriality of mind, mind is outside of the realm of scientific study.

Scott Brisbane argues a case against physicalism and for a form of substance dualism. Using modus ponens, he argues that a physicalist would try to argue that: If we are the result of natural evolutionary forces, then physicalism is true. However on the modus ponens form, if we are the result of natural evolutionary forces, then physicalism is true.

Yet, placing talks of biological origins aside, consider this evolutionary argument framed in the modus ponens form:

1. If we are the result of naturalistic, evolutionary forces, then physicalism is true.
2. Humans are merely the result of naturalistic, evolutionary processes.
3. Therefore, physicalism is true.

Despite differing words, physicalism is assumed for both sides in the first premise, which clearly begs the question. Yet the dualist could turn the argument around to be more favourable:

1. If we are the result of naturalistic, evolutionary forces, then physicalism is true.
2. Physicalism is not true.
3. Therefore, we are not the result of naturalistic evolutionary processes.

If evidence for a non-physical mind is good, then perhaps the latter modus tollens form of the argument should be embraced?

Now, the thing is, we are not simply just bodies or just brains (which is why Markus Gabriel’s (2017) book I am not a Brain is important reading here). If we are not simply bodies or brains, then there is an aspect of our constitution that is not physical. If there is an aspect of our constitution that is not physical, then physicalism is false. If physicalism is false, then science cannot study the mind since the mind is immaterial.

Robledo-Cardona (2021) argues for what he terms “biological materialism”—which is an attempt to naturalize/biologicize the mind. The claim is that consciousness is an evolved biological mechanism that was naturally selected for. He argues that consciousness is a biological mechanism that is composed of parts and organizations—neurons and wiring, respectively. (This is like what Bennett and Hacker call “neural materialism.”) Reading this paper, the author assumes that there is something “it is like” to be certain animals (it is true that there is something that “it is like” to be certain animals) and that this “what-it’s-likeness” is selected-for by natural selection. This assumption is false, since only physical things can be selected, “what-it’s-likeness” isn’t physical, and no argument the author made undercuts any argument made by Fodor and Piatteli-Palmarini (2009). He assumes that natural selection causes biological mechanisms.

Under Robledo-Cardona’s (2021) biological materialism, “a man is a sum of physical objects that is more than an aggregate of parts since these parts are organized. The same would apply to consciousness: a biological mechanism that consists of both parts (neurons) and organization (wiring).” But if we take “Man” to mean a “self”, if we take the self to be “I”, if we take “I” to be simple and not composed of proper parts, and if our brain contains proper parts, then “I” am not my brain and by studying the brain science is not studying “I”, it is only studying a part of “I” that cannot be reduced. “I” cannot be reduced, nor can it be divisible into parts since it is simple (Barnett, 2010). Barnett’s argument from simplicity can be formualted like this:

I am simple; I contain no proper parts (there is no such thing as half an “I”); but my brain contains proper parts (that is, my brain is divisible, there is such a thing as half a brain); therefore “I” am not my brain.

This argument is like Descartes argument from divisibility: My brain can be divided but my mind cannot. If my brain can be divided and my mind cannot, then it follows that my mind is not identical to my brain; the mind is distinct from the brain (that is it is a distinct subtance). “I”—that is, the bearer of mental states—cannot be divided even though my body and its parts can.

Adults are intuitive mind-brain dualists (Forstmann et al, 2015) and people—including children—are overwhelmingly mind-brain dualists (Joubert, 2016). Although this isn’t evidence that dualism is true, I think it is quite suggestive that dualism is intuitive to humans.

The self is not identical to the brain, the body, the central nervous system, nor any part of the body. If the self is not identical to any part of the body, then the self is sui generis—it is unique. The self is an immaterial substance, as shown by Lund (2005: 176-177).

(1) Whatever is secunda facie conceivable for me is something I am secunda facie warranted in believing to be metaphysically possible.
(2) I can clearly and distinctly conceive of myself with exactly my thought properties existing in isolation from all material things (i.e., this state of affairs is secunda facie conceivable for me).(3) Therefore, I am secunda facie warranted in believing that my existing in isolation from all material things (i.e., as disembodied or even in the absence of all material things) is metaphysically possible.
(4) It is not metaphysically possible for a material thing to become immaterial and exist in isolation from all material things;

which, along with (1)–(3), yields:

(5) Therefore, I am secunda facie warranted in believing that I am not a material thing.”

Premise (7) of Hasker’s (2010: 215) Unity of Consciousness argument also establishes that the subject of experience (“I“) isn’t the brain or nervous system:

If the subject is not the brain or the nervous system then it is (or contains as a proper part) a non-physical mind or soul; that is, a mind that is not ontologically reducible to the sorts of entities studied in the physical sciences.

“I” and not any part of my body or its physiological processes is the subject of experience. E. J. Lowe’s Unity argument (Lowe, 2010: 481) further establishes the claim that “I” am not identical with my body or its physiological processes:

I am the subject of all and only my own mental states.

Neither my body as a whole nor any part of it can be the subject of all and only my own mental states.

I am not identical with my body or any part of it.

Morch’s argument in Phenomenal Knowledge Why: The Explanatory Knowledge Argument Against Physicalism (2019: 274) in The Knowledge Argument (2019, ed. by Sam Coleman) establishes that some facts are non-physical and so if some facts are non-physical then it follows that physicalism is false and dualism is true.

1. All physical facts are knowable without experience.

2. Some explanatory facts are no knowable without experience.

3. Therefore, some facts are non-physical.

These arguments establish the claim that the self isn’t identical with anything physical and that some facts are non-physical. So if what I argue here is true—that science can only study what is physical—then the self cannot be studied by science.

Hereditarianism

Before I begin, I need to make a distinction: one between what I call “psychological hereditarianism” and “racial hereditarianism.” Psychological hereditarianism is the claim that mental states/abilities can be genetically transmitted. Racial hereditarianism is the claim that natural selection molded the minds of different racial groups, and that mental differences between racial groups are genetically heritable and so genetically transmitted. As can be seen from the overall argument I’ve been mounting, psychological hereditarianism is false, therefore racial hereditarianism is false.

I personally don’t discount the claims from racial hereditarians on the basis that race doesn’t exist—since I am a pluralist about race. I discount the claim for a variety of reasons. Mainly the facts that (1) IQ tests aren’t construct valid, and so IQ isn’t real; (2) IQ tests are mere knowledge tests and the item content on them are class-specific; (3) the irreducibility of mind to anything physical and (4) natural selection isn’t an explanatory mechanism so it can’t select-for traits, not least psychological traits which are immaterial.

Michael Egnor is a pediatric neuroscientist/professor of neurological surgery, intelligent design advocate and a blogger for the Discovery Institute. Using the long-dead, outdated concept of “heritability” (Moore and Shenk, 2016), Egnor argues that the capacity for abstract thought is material since intellectual activity is passed genetically from generation to generation:

The widely accepted heritability of IQ…is strong evidence for the materiality of the intellect.If intellectual activity is passed from generation to generation by DNA, then the capacity for abstract thought would seem to be material,and not immaterial nor spiritual.

Egnor claims that “What is heritable about IQ is not intellect and will but the capacity for perception, imagination, memory and emotion“—these make up “the material powers of the soul.” He is assuming here that the capacity for perception, imagination, memory, and emotion are physical—material—“powers.” But this claim fails. It fails because the aforementioned things are immaterial, not material. We of course need our organs to function properly in order to be capable of experience—meaning that they are necessary. But this does not license the claim that the “powers” are physical in nature.

This is quite obviously a ridiculous claim. The concept of “heritability” has been scrutinized for decades as an invalid concept (Layzer, 1974; Richardson, 2012, 2022; Joseph, 2014, 2022; Moore and Shenk, 2016; Charney, 2012, 2017, 2020). “Heritability” estimates for IQ are said to range from .5-.8, based on a range of twin, adoption, and family studies. However, the actual—unreported—“heritability” of IQ in the MISTRA was 0% (Joseph, 2022)! The fact of the matter is, the methods that hereditarians use are highly confounded and do not license the conclusions they make from the data they have. Further, their newest attempt at proving that psychological traits reduce to genes is polygenic scores (PGS). However, PGS, too, has similar pitfalls as GWAS (since they are derived from GWAS data). The hereditarian must construct an valid deductive argument in which the conclusion is the phenomena to be explained; they must provide an explanans that has a law-like generalization; and they need to show that the preceeding premises have empirical content and are true. In absence of an answer to this challenge, the claims hereditarians make about PGS fail. Moreover, the larger a dataset is, the higher chance of spurious correlations (Calude and Longo, 2016), and there are nothing but spurious correlations that arise from GWAS and PGS (Richardson and Jones, 2019).

Back in 2019, I published an article with 4 sections with arguments against hereditarianism. One of the arguments I provided was one that showed that anything that cannot be described in physical terms using words that only refer to material properties is immaterial. And since the mind cannot be explained in that way, it is therefore immaterial. The other argument I provided stated that if physicalism is true then all facts can be stated using a physical vocabulary but facts about the mind cannot so the mind must not be physical. Philosopher of mind William Jaworski provided a similar argument against materialism and why it has nothing to do with the mind since not everything can be explained using a physical vocabulary and that since explanations of biology appeal to biological organization/structure, and there are good reasons to believe that such descriptions and explanations cannot be eliminated, reduced or paraphrased in physical terms, then materialism must be false (Jaworski, 2016).

Hereditarianism, in my view, assumes a form of mind-brain identity as I have argued in the past. And because of this, hereditarianism falls prey to the mereological fallacy—which is when one ascribes psychological predicates to the brain when they are predicates of the whole human. This is seen in hereditarian neuroimaging studies, for example. Contemporary hereditarians aren’t using phrenological methods anymore, nor are they really measuring skulls anymore and ascertaining “qualities” of the person from the skull. But there is a “new phrenology” and this new phrenology is cognitive neuroimaging.

Recall how above I stated that minds are intentionally constituted. If mind-body reduction is possible, then there must be functional definitions of mental properties in terms of lower-level properties. But, drawing on Kripke’s normativity argument, Heikinheimo argues that such definitions are not attainable for mental properties and this, then, has implications for the attempted explanations of intentional states in terms of brain states. There must be causal-functional analyses of meaning and this is just not possible. Bilgrami (2006) in Self-Knowledge and Resentment argued that we have privileged access to our intentional states and that human agency and the intentional states of human agents are irreducibly normative. One reason why is the simple fact that science is third-personal and cannot possibly study first-personal states (Nagel, 1974). Another reason is that intentional states don’t reduce to physical states. And so, if minds are intentionally constituted, then it follows that minds are irreducible and therefore non-physical.

We have fMRI machines. Using these machines, we can measure small changes in blood flow in the brain—we can basically see which parts of the brain are active during certain tasks. Physicalists may then claim that if you do a task and a certain part of the brain lights up, the identity between the two shows that we can either read minds (a dubious claim) or we know which part of the brain is responsible for carrying out the task in question. The use of fMRI has been used by hereditarian researchers to attempt to localize cognition to certain aspects of the brain and outlandish claims have been made that one’s “intelligence” can be gleaned by just resting in an fMRI machine. Unfortunately for these theorists (eg, Jung and Haier, 2007), conceptual arguments undercut the claim that cognition can be localized to certain parts of the brain (Uttal, 2012). In my view, newer forms of hereditarianism have begun to lean toward a type of mind-brain identity—hereditarians assume physicalism is true and either attempt to reduce mind to genes, brain states, or neural states. But the falsity of mind-brain identity and the conceptual errors in attempting to localize cognition to parts of the brain means that this research program is a conceptual failure.

It is impossible to localize cognitive processes in the brain—effectively “pinpointing” where in the brain a certain cognitive task is occurring. This is due to many conceptual and methodological issues that Uttal (2001; 2012) brings up. There is neurophysiological variability in subjects and we can’t just pool neuroimaging studies together to get “a look” at an active brain and then correlate cognitive processes to it. Therefore, the attempts of hereditarians who use this research fail—conceptually—as well as empirically. Such follys like this arise since the assumption is the mind is what the brain does—basically, that the mind is merely the brain’s physiology at work. But such a claim needs to be rejected, since physicalism is false. And if physicalism is false, as has been successfully argued, then hereditarianism is false.

Speculative claims of “brain-based mind reading” have been made stating that we could use this technique to read the brains—and therefore minds—of, say, prisoners and see if they have or would have done something under a certain condition (Glannon, 2017). As Glannon rightly notes, fMRI detects brain function but not mental function so mind reading wouldn’t be possible. Since the mind refers to mental states, and we can correlate brain states with mental states, then there has to be a material basis of the mind and it must be able to be studied by science (Rainey et al, 2021).

The fact of the matter is, claims such as these are assuming that thought has determinate content. But going back to Ross’ (1992) argument above, we cannot ever “read minds” in a way that a physicalist wants to. Fortunately, mind privacy is different from brain privacy in that we can scan brains but we cannot scan minds. External access to one’s mind does not exist—it is completely internal. So mental privacy cannot be breached (Gilead, 2015).

But what [further knowledge of the brain] cannot do even in principle is fix a single determinate interpretation of those thoughts, or reduce them entirely to neural activity. So, no entirely empirical methods could, even in principle, allow us to “read” someone’s thoughts in anything more than the loose and familiar sense in which we can already do so. — Ed Feser, Mindreading?

Anything material can be studied by science. The brain is material. So the brain can be studied by science. Thoughts are immaterial. So thoughts cannot be studied by science. The only way for scientists to be able to study the mind is if the mind is the brain—if the mind reduces to or is identical to the brain—but this is impossible due to what is argued above. So a science of the mind is impossible and hereditarianism fails.

The failure of psychometrics in measuring the mind

Psychometrics has been touted as giving us the ability to measure the human mind. There are many baked-in assumptions, though, that make the claim that psychometry is a measurement enterprise fail.

Most important for the claim that psychometrics is a science and that the mind is a measurable object is that we can therefore “number” and “rank” the minds of people using psychological tests. There are many types of measurement tools we can use to understand human bodies, like a scale and a ruler to measure height, and these are physical measures. For instance, when one steps on a scale they then see a number in a few seconds. What this number means is their weight—it is basically their mass. A unit of measurement is a magnitude of a quantity—that is, a physical quantity. Meters measure length, kilograms measure weight, and seconds measure time. Thus, weight is a measure since it satisfies the basic tenets of metrication.

Take the example of length. If we want to know how long, say, a stick was, then we need to satisfy three properties: (1) The measured object is the stick; (2) the length of the stick is the object of measurement; and (3) the measurement unit would be inches, centimeters, feet, etc.

Now that I have given some examples on what we claim to measure and how we know it is measured, I will now turn to how psychological measurement fails.

When it comes to psychiatric and psychological tests, it needs to be stated that they get a lot of their “data” from questionnaires that give numerical values which then gives the illusion of the ability of psychologists/psychiatrists to measure human mental states and put a number to them. This issue is put well by Berka (1983: 202-203):

…the methodologists of extraphysical measurement are very well aware that, unlike in physical measurement, it is here often not at all clear which properties are the actual object of measurement, more precisely, the object of scaling or counting, and what conclusions can be meaningfully derived from the numerical data concerning the assumed subject matter of investigation.

Put another way, psychometricians don’t actually conceptualize an object of measurement that meets the minimal requirements of measurement. The point is, argues Berka (1983) and Nash (1990), that there is no measurement unit for psychological kinds, and so if there is no measurement unit for psychological kinds, then the claim that mental “measurement” is possible fails.

In his recent book In the Know: Debunking 35 Myths about Human Intelligence, Warne (2020:12) argues that just as kg and lbs are measurements of weight, so too is IQ a measurement of intelligence:

IQ, or an IQ score, is not the same as intelligence or g. Instead, IQ is a measure of general intelligence. To use an analogy, just as kilograms and pounds are measures of weight, IQ is a measure of intelligence. IQ is not intelligence itself any more than the number on a scale is a person’s weight. In both cases, the number is a measurement and not the real topic of interest.

How strange that Warne does not discuss measurement units, specified measured objects or objects of measurement for the “trait” that the book is about. It’s because he—quite obviously—CAN’T. This is in stark contrast to Richard Haier’s (2011: 463) article The Biological Basis of Intelligence in The Cambridge Handbook of Intelligence where he claims that “Even polygenetic scores or DNA profiles might provide new definitions of intelligence.” Haier (2018), in his article A View from the Brain in the book The Nature of Human Intelligence, admits that there is “no measurement of intelligence comparable to a unit of distance or weight.” This fact means that the “measurement” of psychological traits is impossible because they aren’t physical and lack physical properties. Dario de Judicibus (2015) tries to argue that “intelligence” “is the ability to develop and manage relational schemas“, which of course depend on being exposed to the item content, which is class-specific. This, contrary to his claims, is NOT an “operational definition.” There is a list of 71 different “definitions” of “intelligence“, and they all have intentional content/mentalistic wordings in them, so my argument above about being able to describe psychological traits in words that refer only to physical properties still holds. The hereditarian has to give a definition without using mental phrases, and if they cannot describe the mental in words that refer only to material properties then it is immaterial and therefore immeasurable. In any case, the definitions that hereditarians have given over the years fail, since it does not refer to a single measurable property. And attempting an analogy between temperature and IQ and height and weight

Construct validity is the degree to which a test or measure assesses what the measurement tool is supposed to measure. In this case, construct validity refers to how well IQ tests “measure” “intelligence.” But, as we know from the arguments above, psychological traits are immaterial and what is immaterial is immeasurable so IQ tests can’t possibly be a measure of anything psychological. I made an argument using modus tollens back in 2019 arguing against the claim that IQ tests are construct valid:

Premise 1: If the claim “IQ tests test intelligence” is true, then IQ tests must be construct valid.
Premise 2: IQ tests are not construct valid.
Conclusion: Therefore, the claim “IQ tests test intelligence” is false. (modus tollens, P1, P2)

If IQ is real, then IQ is measurable. If IQ is measurable then IQ is physical. So if IQ is real, then IQ is physical. The main aspect of IQ test-taking is thinking, which is irreducible. If thinking is irreducible, then it cannot be physical. If thinking isn’t physical, then IQ can’t be physical. So IQ can’t be measured. Therefore IQ isn’t real.

What IQ tests are are mere class-specific knowledge tests:

If IQ tests are merely class-specific knowledge tests, then they include class-specific item content. IQ tests include class-specific item content. Therefore, IQ tests are merely class-specific knowledge tests.

Over the past 100 years such tests have been used for malicious reasons, like to sterilize those who score low on the test (see the story of Carrie Buck). Who is or is not “intelligent” was decided a priori, by the test’s constructors, and so they designed the test to fit their desires. This means that IQ is arbitrary. In any case, as I have successfully argued here, hereditarianism is false. And if it is false and we believe it to be true, then that could cause bad outcomes policy-wise for certain groups. See the argument for banning IQ tests below:

(P1) The Hereditarian Hypothesis is false
(P2) If the Hereditarian Hypothesis is false and we believed it to be true, then policy A could be enacted.
(P3) If Policy A is enacted, then it will do harm to group G.
(C1) If the Hereditarian Hypothesis is false and we believed it to be true and policy A is enacted, then it will do harm to group G (Hypothetical Syllogism, P2, P3).
(P4) If the Hereditarian Hypothesis is false and we believed it to be true and it would harm group G, then we should ban whatever led to policy A.
(P5) If Policy A is derived from IQ tests, then IQ tests must be banned.
(C2) Therefore, we should ban IQ tests (Modus Ponens, P4, P5).

IQ tests aren’t construct valid, they aren’t true measures, they are mere class-specific knowledge tests, and so putting this all together, we must ban the use of IQ tests, since they don’t measure what they purport to and, due to the biased nature of the tests, we could harm certain groups on the basis of their test scores.

Thus, what psychometrics is isn’t a measurement enterprise, it is merely a political ring (Garrison, 2009). Standardized tests (which IQ tests are as well) “exist to assess social function” (Garrison, 2009: 5). Psychometricians render “mere application of number systems to objects” (Garrison, 2004: 63), so they just assume that their object of measurement is quantitative, without showing that it actually is.

Uher (2021) states that “psychometrics does not establish systematic relations to individuals’ minds as needed for measurement and that, consequently, psychometric results should not be used to make decisions about persons.” It is not a fundamental measurement, and analogies to physical measurement are false. Psychometricians just assume, without argument or showing how, that psychological traits are measurable and thusly quantitative. The claim that psychology is measurable is a “highly questionable idea” (Franz, 2022). Thus, according to Michell (2008), psychometrics is a pathological science, where a pathological science is when a hypothesis is accepted as true without testing it, and as so happened with psychometrics, it is assumed to be quantitative without it being shown that it is indeed the case.

Conclusion

The falsity of physicalism has been argued by many authors (eg., Chalmers, 1996, 2010; Koons and Bealer, 2010; Hasker, 2001; Lowe; Lavazza and Robinson, 2014 ; Robinson, 2016; Swinburne, 2019). As I have successfully argued here, if there are 2 kinds of substances—that is, if there is mental stuff and physical stuff—then a science of the mind is impossible since the mental stuff isn’t the same stuff as the physical stuff which is the object of scientific investigation.

A science of the mind is possible if, and only if, the mind is a physical object. If the mind is an immaterial object, then it cannot be studied by science, since science only studies the physical. This also has implications for AI, since AI (computers) are made up of a suite of physical parts and a mind isn’t made up of a suite of physical parts. Knowing this, this allows me to make this argument against the possibility of AI ever being able to think.

Only things with minds can think. Purely physical things lack minds. So purely physical things can’t think. Thinking is an action and machines don’t act so machines don’t think.

So now, after laying out the evidence and arguments, I can now make this argument:

If dualism is true, then it follows that the mind is not physical. If the mind is not physical (and if the mind is not a mere product of the brain), then it cannot be studied by science, since science studies what is a part of the natural world, that is it studies what is physical. Though it could be said that mind is part of the natural world, that doesn’t mean that it is physical and if it isn’t physical then it’s not amenable to scientific investigation. This means that the ultimate aim of psychometry and psychology (and by consequence, hereditarianism) is simply impossible. Mind-brain monism is an unconfirmed hypothesis (Joubert, 2016)—it is merely assumed that physicalism is true by people like psychologists and that, for example, that psychology can be reduced to the physical.

Indeed, even ignoring the arguments for the irreducibility of mind, it would still be impossible for psychology to be an empirical science (Smedslund, 2016). Moreover, psychological phenomena aren’t manipulable nor controllable, so they are immeasurable and a Galliean revolution in psychology isn’t possible if the quantification problem isn’t solved (and I claim that it’s a logical impossibility for them to be quantified) (Trendler, 2009). This also has implications for “general intelligence” or “g” theory and other hypothetical constructs—for if psychological traits are immeasurable, then claims that “g” is measurable fail, too. And there is the fact that there are no psychophysical or psychological laws, and that the mental is irreducible to the physical, which also mean that attempts to measure the mind will fail.

Although I have come to my conclusion that psychological traits are immeasurable from different avenues, other authors have (rightly) argued the claim that psychometrics isn’t measurement since psychology isn’t physical. And if it’s not physical—as I have successfully argued here—then dualism is true and psychology can’t be amenable to scientific investigation.