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One debate in the philosophy of science is whether or not a scientific hypothesis should make testable predictions or merely explain only what it purports to explain. Should a scientific hypothesis H predict previously unknown facts of the matter or only explain an observation? Take, for example, evolutionary psychology (EP). Any EP hypothesis H can speculate on the so-called causes that led a trait to fixate in a biological population of organisms, but the claim that they can do more than that—that is, that they can generate successful predictions of previously unknown facts not used in the construction of the hypothesis—but that’s all they can do. The claim, therefore, that EP hypotheses are anything but just-so stories, is false.
Prediction and novel facts
For example, Einstein’s theory of general relativity predicted the bending of light, which was a novel prediction for the hypothesis (see pg 177-180 for predictions generated from Einstein’s theory). Fresnel’s wave theory of light predicted different infraction fringes to the prediction of the white spot—a spot which appears in a circular object’s shadow due to Fresnel diffraction (see Worrall, 1989). So Fresnel’s theory explained the diffraction and the diffraction then generated testable—and successful—novel predictions (see Magnus and Douglas, 2013). There is an example of succeful novel prediction. Ad hoc hypotheses are produced “for this” explanation—so the only evidence for the hypothesis is, for example, the existence of trait T. EP hypotheses attempt to explain the fixation of any trait T in humans, but all EP hypotheses do is explain—they generate no testable, novel predictions of previously unknown facts.
A defining feature of science and what it purports to do is to predict facts-of-the-matter which are yet to be known. John Beerbower (2016) explains this well in his book Limits of Science? (emphasis mine):
At this point, it seems appropriate to address explicitly one debate in the philosophy of science—that is, whether science can, or should try to, do more than predict consequences. One view that held considerable influence during the first half of the twentieth venture is called the predictivist thesis: that the purpose of science is to enable accurate predictions and that, in fact, science cannot actually achieve more than that. The test of an explanatory theory, therefore, is its success at prediction, at forecasting. This view need not be limited to actual predictions of future, yet to happen events; it can accommodate theories that are able to generate results that have already been observed or, if not observed, have already occurred. Of course, in such cases, care must be taken that the theory has not simply been retrofitted to the observations that have already been made—it must have some reach beyond the data used to construct the theory.
That a theory or hypothesis explains observations isn’t enough—it must generate successful predictions of novel facts. If it does not generate any novel facts-of-the-matter, then of what use is the hypothesis if it only weakly justifies the phenomenon in question? So now, what is a novel fact?
A novel fact is a fact that’s generated by hypothesis H that’s not used in the construction of the hypothesis. For example, Musgrave (1988) writes:
All of this depends, of course, on our being able to make good the intuitive distinction between prediction and novel prediction. Several competing accounts of when a prediction is a novel prediction for a theory have been produced. The one I favour, due to Elie Zahar and John Worral says that a predicted fact is a novel fact for a theory if it was not used to construct that theory — where a fact is used to construct a theory if it figures in the premises from which that theory was deduced.
Mayo (1991: 524; her emphasis) writes that a “novel fact [is] a newly discovered fact—one not known before used in testing.” So a fact is novel when it predicts a fact of the matter not used in the construction of the hypothesis—i.e., a future event. About novel predictions, Musgrave also writes that “It is only novel predictive success that is surprising, where an observed fact is novel for a theory when it was not used to construct it.” So hypothesis H entails evidence E; evidence E is not used in the construction of hypothesis H, therefore E is novel evidence for hypothesis H.
To philosopher of science Imre Lakatos, a progressive research program is one that generates novel facts, whereas a degenerating research program either fails to generate novel facts or the predictions made that were novel continue to be falsified, according to Musgrave in his article on Lakatos. We can put EP in the “degenerating research program, as no EP hypothesis generates any type of novel prediction—the only evidence for the trait is the existence of the trait.
The term “just-so stories” comes from Rudyard Kipling Just-so Stories for Little Children. Then Gould and Lewontin used the term for evolutionary hypotheses that can only explain and not predict future as-of-yet-known events. Law (2016) notes that just-so stories offer “little in the way of independent evidence to suggest that it is actually true.” Sterelny and Griffiths (1999: 61) state that just-so stories are “… an adaptive scenario, a hypothesis about what a trait’s selective history might have been and hence what its function may be.” Examples of just-so stories covered on this blog include: beards, FOXP2, cartels and Mesoamerican ritual sacrifice, Christian storytelling, just-so storytellers and their pet just-so stories, the slavery hypertension hypothesis, fear of snakes and spiders, and cold winter theory. Smith (2016: 278) has a helpful table showing ten different definitions and descriptions of just-so stories:
So the defining criterion for just-so stories is that there must be independent evidence to believe the proposed explanation for the existence of the trait. There must be independent reasons to believe a certain hypothesis, as the defining feature of a scientific hypothesis or theory is whether or not it can predict yet-to-happen events. Though, as Beerbower notes, we have to be careful that we do not retrofit the observations.
One can make an observation. Then they can work backward (what Richardson (2007) elicits is “reverse engineering”) and posit (speculate about) a good-sounding story (just-so storytelling) to explain this observation. Reverse engineering is “a process of figuring out the design of a mechanism on the basis of an analysis of the tasks it performs” (Buller, 2005: 92). Of course, the just-so storyteller can then create a story to explain the fixation of the trait in question. But that’s only (purportedly) the explanation of why the trait came to fixation for us to observe it today. There are no testable predictions of previously unknown facts. So it’s all storytelling—speculation.
The theory of natural selection is then deployed to attempt the explain the fixation of trait T in any population. It is true that a hypothesis is weakly corroborated by the existence of trait T, but what makes it a just-so story is the fact that there are no successful predictions of previously unknown facts,
When it comes to EP, one can say that the hypothesis “makes sense” and it “explains” why trait T still exists and went to fixation. However, the story only “makes sense” because there is no other way for it to be—if the story didn’t “make sense”, then the just-so storyteller wouldn’t be telling the story because it wouldn’t satisfy their aims of “proving” that a trait is an adaptation.
Smith (2016:277-278) notes 7 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.
EP is most guilty of (3), (4), (5), (6), and (7). It is guilty of (3) in that it hardly ever posits other explanations for trait T, it’s always “adaptation”, as EP is an adaptationist paradigm. It is guilty of (4) perhaps the most. That trait T still exists and is useful for this today is not evidence that trait T was selected-for its use as we see it today. This then leads to (5) which is the misuse of reverse engineering. Just-so stories are ad hoc (“for this”) explanations and these types of explanations are ad hoc if there is no independent data for the hypothesis. Of course, it is guilty of (7) in that it attempts to explain, of course, unique events in human evolution. Many problems exist for evolutionary psychology (see for example Samuels, 1998; Lloyd, 1999; Prinz, 2006;), but the biggest problem is the ability of any hypothesis to generate testable, novel predictions. Smith (2016: 279) further writes that:
An important weakness in the use of narratives for scientific purposes is that the ending is known before the narrative is constructed. Merton pointed out that a “disarming characteristic” of ex post facto explanations is that they are always consistent with the observations because they are selected to be so.
Bo Winegard, in his defense of just-so storytelling, writes “that inference to the best explanation most accurately describes how science is (and ought to be) practiced. According to this description, scientists forward theories and hypotheses that are coherent, parsimonious, and fruitful.” However, as Smith (2016: 280-281) notes, that a hypothesis is “coherent”, “parsimonious” and “fruitful” (along with 11 more explanatory virtues of IBE, including depth, precision, consilience, and simplicity) is not sufficient to accept IBE—IBE is not a solution to the problems proposed by the just-so story critics as the slew of explanatory virtues do not lend evidence that T was an adaptation and thusly do not lend evidence that hypothesis H is true.
Simon (2018: 5) concludes that “(1) there is much rampant speculation in evolutionary psychology as to the reasons and the origin for certain traits being present in human beings, (2) there is circular reasoning as to a particular trait’s supposed advantage in adaptability in that a trait is chosen and reasoning works backward to subjectively “prove” its adaptive advantage, (3) the original classical theory is untestable, and most importantly, (4) there are serious doubts as to Natural Selection, i.e., selection through adaptive advantage, being the principal engine for evolution.” (1) is true since that’s all EP is—speculation. (2) is true in evolutionary psychologists notice trait T and that, since it survived today, there must be a function it performs for why natural selection “selected” the trait to propagate in species (though selection cannot select-for certain traits). (3) it is untestable in that we have no time machine to go back and watch how trait T evolved (this is where the storytelling narrative comes in: if only we had a good story to tell about the evolution of trait T). And finally, (4) is also true since natural selection is not a mechanism (see Fodor, 2008; Fodor and Piattelli-Palmarini, 2010).
EP exists in an attempt to explain so-called psychological adaptations humans have to the EEA (environment of evolutionary adaptiveness). So one looks at the current phenotype and then looks to the past in an attempt to construct a “story” which shows how a trait came to fixation. There are, furthermore, no hallmarks of adaptation. When one attempts to use selection theory to explain the fixation of trait T, they must wrestle with spandrels. Spandrels are heritable, can increase fitness, and they are selected as well—as the whole organism is selected. This also, of course, falls right back to Fodor’s (2008) argument against natural selection. Fodor (2008: 1) writes that the central claim of EP “is that heritable properties of psychological phenotypes are typically adaptations; which is to say that they are typically explained by their histories of selection.” But if “psychological phenotypes” cannot be selected, then the whole EP paradigm crumbles.
This is why EP is not scientific. It cannot make successful predictions of previously unknown facts not used in the construction of the hypothesis, it can only explain what it purports to explain. The claim, therefore, that EP hypotheses are anything but just-so stories is false. One can create good-sounding narratives for any type of trait. But that they “sound good” to the ear, and are “plausible” are not reasons to believe that the story told is true.
Are all hypotheses just-so stories? No. Since a just-so story is an ad hoc hypothesis and a hypothesis is ad hoc if it cannot be independently verified, then a hypothesis that makes predictions which can be independently verified are not just-so stories. There are hypotheses that generate no predictions, ad hoc hypotheses (where the only evidence to believe H is the existence of trait T), and hypotheses that generate novel predictions. EP is the second of these—the only evidence we have to believe H is true is that trait T exists. Independent evidence is a necessary condition of science—that is, the ability of a hypothesis to predict novel evidence is a necessary condition for science. That no EP hypothesis can generate a successful novel prediction is evidence that all EP hypotheses are just-so stories. So for the criticism to be refuted, one would have to name an EP hypothesis that is not a just-so story—that is, (1) name an EP hypothesis, (2) state the prediction, and then (3) state how the prediction follows from the hypothesis.
To be justified in believing hypothesis H in explaining how trait T became fixated in a population there must be independent evidence for this belief. The hypothesis must generate a novel fact which was previously unknown before the hypothesis was constructed. If the hypothesis cannot generate any predictions, or the predictions it makes are continuously falsified, then the hypothesis is to be rejected. No EP hypothesis can generate successful predictions of novel facts and so, the whole EP enterprise is a degenerative research program. The EP paradigm explains and accommodates, but no EP hypothesis generates independently confirmable evidence for any of its hypotheses. Therefore EP is not a scientific program and just-so stories are not scientific.
Mexican drug cartels kill in some of the most heinous ways I’ve ever seen. I won’t link to them here, but a simple Google search will show you the brutal, heinous ways in which they kill rivals and snitches. Why do they kill like this? I have a simple just-so story to explain it: Mexican drug cartels—and similar groups—kill the way they do because they are descended from Aztecs, Maya, and other similar groups who enacted ritual sacrifices to appease their gods.
For example, Munson et al (2014) write:
Among the most noted examples, Aztec human sacrifice stands out for its ritual violence and bloodshed. Performed in the religious precincts of Tenochitlan, ritual sacrifice was a primary instrument for social integration and political legitimacy that intersected with militaristic and marketplace practices, as well as with beliefs about the cosmological order . Although human sacrifice was arguably less common in ancient Maya society, physical evidence indicates that offerings of infant sacrifices and other rituals involving decapitation were important religious practices during the Classic period , .
The Aztecs believed that sacrificial blood-letting appeased their gods who fed on the human blood. They also committed the sacrifices “so that the sun could continue to follow its course” (Garraud and Lefrere, 2014). Their sun god—Uitzilopochtli—was given strength by sacrificial bloodletting, which benfitted the Aztec population “by postponing the end of the world” (Trewby, 2013). The Aztecs also sacrificed children to their rain god Tlaloc (Froese, Gershenson, and Manzanilla, 2014). Further, the Aztec ritual of cutting out still-beating hearts arose from the Maya-Toltec traditions (Ceruti, 2015).
Regarding Aztec sacrifices, Winkelman (2014: 50) writes:
Anthropological efforts to provide a scientific explanation for human sacrifice and cannibalism were initiated by Harner (1970, 1977a, 1977b). Harner pointed out that the emic normalcy of human sacrifice—that it is required by one’s gods and religion—does not alone explain why such beliefs and behaviours were adopted in specific societies. Instead, Harner proposed explanations based upon causal factors found in population pressure. Harner suggested that the magnitude of Aztec human sacrifice and cannibalism was caused by a range of demographic-ecological conditions—protein shortages, population pressure, unfavourable agricultural conditions, seasonal crop failures, the lack of domesticated herbivores, wild game depletion, food scarcity and famine, and environmental circumscription limiting agricultural expansion.
So, along with appeasing and “feeding” their gods, there were sociological reasons for why they committed human sacrifices, and even cannibalism.
When it comes to the Maya (a civilization that independently discovered numerous things while being completely isolated from other civilizations), they had a game called pok-ta-tok—due to the sound the ball made when the players hit it or it fell on the ground. Described in the Popul Vuh (the Ki’iche Maya book that lays out their creation myth), humans and the lords of the Underworld played this game. The Maya Hero Twins Hunahpu and Xbalanque went to the Underworld to do battle against the lords of the Underworld—called Xibalba (see Zaccagnini, 2003: 16-20 for a description of the myth Maya Hero Twins and how it relates to pok-ta-tok and also Myers (2002: 6-13)). See Tokovinine (2002) for more information on pok-ta-tok.
This game was created by the Olmec, a pre-cursor people to the Maya, and later played by the Aztecs. The court was seen as the portal to Xibalba. The Aztec then started playing the game and continued the tradition of murdering the losing team. The rubber ball  weighed around ten pounds, and so it must have caused a lot of bruising and head injuries to players who got hit in the head and body with the ball—as they used their forearms and thighs to pass the ball. (See The Brutal and Bloody History of the Mesoamerican Ball Game, Where Sometimes Loss Was Death.)
According to Zaccagnini (2003: 6) “The ballgame was executed for many reasons, which include social functions, for recreation or the mediation of conflict for instance, the basis for ritualized ceremony, and for political purposes, such as acting as a forum for the opposing groups to compete for political status (Scarborough 1991:141).” Zaccagnini (2003: 7-8) states that the most vied-for participants in the game were captured Maya kings and that they were considered “trophies” of the kings’ people who captured them. Those who were captured had to play the game and they were—essentially—fighting (playing) for their lives. The Maya used the game for a stand-in for war, which is seen in the fact that they played with invading Toltecs in their region (Zaccagnini, 2003: 8).
Death by decapitation occurred to the losers of the game, and, sometimes, skulls of the losing players were used inside of the rubber balls they used to play the game. The Maya word for ball—quiq—literally means “sap” or “blood” which refers to how the rubber ball itself was constructed. Zaccagnini (2003: 11) notes that “The sap can be seen as a metaphoric blood which flows from the tree to give rise to the execution of the ballgame and in this respect, can imply further meaning. The significance of blood in the ballgame, which implies death, is tremendous and this interpretation of the connection of blood and the ball correlated with the notion that the ball is synonymous with the human head is important.” (See both Zaccagnini, (2003) and Tokovinine (2002) for pictures of Maya hieroglyphs which depict winning and losing teams, decapitations, among other things.)
So, the game was won when the ball passed through the hoop which was 20-30 feet in the air, hanging from a wall. These courts, too, were linked to celestial events that occurred (Zaccagnini, 2003). It has been claimed that the ball passing through the hoop was a depiction of the earth passing through the center of the Milky Way.
Avi Loeb notes that “The Mayan culture collected exquisite astronomical data for over a millennium with the false motivation that such data would help predict its societal future. This notion of astrology prevented the advanced Mayan civilization from developing a correct scientific interpretation of the data and led to primitive rituals such as the sacrifice of humans and acts of war in relation to the motions of the Sun and the planets, particulary Venus, on the sky.” The planets and constellations, of course, were also of importance in the Maya society. Šprajc (2018) notes that “Venus was one of the most important celestial bodies”, while also stating:
Human sacrifices were believed necessary for securing rain, agricultural fertility, and a proper functioning of the universe in general. Since the captives obtained in battles were the most common sacrificial victims, the military campaigns were religiously sanctioned, and the Venus-rain-maize associations became involved in sacrificial symbolism and warfare ritual. These ideas became a significant component of political ideology, fostered by rulers who exploited them to satisfy their personal ambitions and secular goals. In sum, the whole conceptual complex surrounding the planet Venus in Mesoamerica can be understood in the light of both observational facts and the specific socio-political context.
The relationship between the ballgame, Venus, and the fertility of the land in regard to the agricultural cycle and Venus is also noted by Šprajc (2018). The Maya were expert astronomers and constantly watched the skies and interpreted certain things that occurred in the cosmos in the context of their beliefs.
I have just described the ritualistic sacrifices of the Maya. This, then, is linked to my just-so story, which I first espoused on Twitter back in July of 2018:
Then in January of this year, white nationalist Angelo John Gage unironically used my just-so story!:
Needless to say, I found it hilarious that it was used unironically. Of course, since Mexicans and other Mesoamericans are descendants of the Aztec, Maya and other Indian groups native to the area, one can make this story “fit with” what we observe today. Going back to the analysis above of the Maya ballgame pok-ta-tok, the Maya were quite obviously brutal in their decapitations of the losing teams of the game. Since they decapitated the losing players, this could be seen as a sort of cultural transmission of certain actions (though I strongly doubt that that is why cartels and similar groups kill in the way they do—the exposition of the just-so story is just a funny joke to me).
In sum, my just-so story for why Mexican drug cartels and similar groups kill in the way they do is, as Smith (2016: 279) notes “always consistent with the [observation] because [it is] selected to be so.” The reasons why the Aztecs, Maya, and other Mesoamerican groups participated in these ritualistic sacrifices are numerous: appeasing gods, for agricultural fertility, to cannibalism and related things. There were various ecological reasons why the Aztecs may have committed human sacrifice, and it was—of course—linked back to the gods they were trying to appease.
The ballgame they played attests to the layout of their societies and how it made their societies function in the context of their beliefs regarding appeasing their numerous gods. When the Spanish landed at Mesoamerica and made first contact with the Maya, it took them nearly two centuries to defeat them—though the Maya population was already withering away due to climate change and other related factors (I will cover this in a future article). Although the Spanish destroyed many—if not most—Maya codices, we can glean important information of their lifestyle and how and why they played their ballgame which ended in the ritualistic sacrifice of the losing team.
Evolutionary psychology (EP) purports to explain how and why humans act the way they do today. It is a framework that assumes that certain mental/psychological traits were useful in the EEA (Environment of Evolutionary Adaptedness) and thusly were selected for over time. It assumes that traits are adaptations then “works backward” by reverse engineering. Reverse engineering is the process of figuring out the design of the mechanism based on its function. (Many problems exist there which will be covered in the future; see also Evolutionary Psychology: The Burdens of Proof by Lloyd, 1999). But let’s discuss snakes and other animals that we have fears of today; is there an evolutionary basis for said behavior and can we really know if there was?
Fear of snakes and spiders
Ohman (2009: 543) writes that “Snakes … have a history measured in many millions of years of shaping mammalian and primate evolution in important respects” and that “snakes … are promising tools for probing the emotional ramifications of deep evolutionary heritages and their interaction with the current environment.” Are they promising tools, though? Were there that many snakes in our EEA that made it possible for us to ‘evolve’ these types of ‘fear modules’ (Ohman and Mineka, 2001)? No, it is impossible for our responses to snakes—along with some other animals—to be an evolved response to what occurred in our EEA because the number of venomous, dangerous snakes to humans and our ancestors was, in reality, not all that high.
Ohman and Mineka (2003: 5-6) also write that “the human dislike of snakes and the common appearances of reptiles as the embodiment of evil in myths and art might reflect an evolutionary heritage” and “fear and respect for reptiles is a likely core mammalian heritage. From this perspective, snakes and other reptiles may continue to have a special psychological significance even for humans, and considerable evidence suggests this is indeed true. Furthermore, the pattern of findings appears consistent with the evolutionary premise.”
Even the APA says that an evolutionary predisposition to fear snakes—but not spiders—exists in primates (citing research from Kawai and Koda, 2016). Conclusions such as this—and there are many others—arise from the ‘fact’ that, in our EEA, these animals were harmful to us and, over time, we evolved to fear snakes (and spiders), but there are some pretty big problems with this view.
Jankowitsch (2009) writes that “Fear of snakes and spiders, which are both considered to be common threats to survival in early human history, are not thought to be innate characteristics in human and nonhuman primates, learned.” For this to be the case, however, there would need to be many spiders and snakes in our EEA.
Philosopher of science Robert C. Richardson, in his book Evolutionary Psychology and Maladapted Psychology (Richardson, 2007) concludes that EP explanations are speculation disguised as results. He says that the stories that state that we evolved to evolved to fear snakes and spiders lack evidence. Most spiders aren’t venomous and pose no risk to humans. In the case of snakes, one quarter are poisonous to humans and we’d have to expect this ‘module’ to evolved on the basis of a minority of snakes that are poisonous to humans:
On this view, at least some human fears (but not all) are given explanations in evolutionary terms. So a fear of snakes or spiders, like our fear of strangers and heights, serves to protect us from dangers. Having observed that snakes and spiders are always scary, and not only to humans, but other primates, Steven Pinker (1997: 386) says “The common thread is obvious. These are the situations that put our evolutionary ancestors in danger. Spiders and snakes are often venomous, especially in Africa…. Fear is the emotion that motivated our ancestors to cope with the dangers they were likely to face” (cf. Nesse 1990). This is a curious view, actually. Spiders offer very little risk to humans, aside from annoyance. Most are not even venomous. There are perhaps eight species of black widow, one of the Sydney funnel web, six cases of brown recluses in North and South America, and one of the red banana spider in Latin America. These do present varying amounts of risk to humans. They are not ancestrally in Africa, our continent of origin. Given that there are over 37,000 known species of spiders, that’s a small percentage. The risk from spiders is exaggerated. The “fact” that they are “always scary” and the explanation of this fact in terms of the threat they posed to our ancestors is nonetheless one piece of lore of evolutionary psychology. Likeways, snakes have a reputation among evolutionary psychologists that is hardly deserved. In Africa, some are truly dangerous, but by no means most. About one quarter of species in Uganda pose a threat to humans, though there is geographic variability. It’s only in Australia—hardly our point of origin—that the majority of snakes are venomous. Any case for an evolved fear of snakes would need to be based on the threat from a minority. In this case too, the threat seems exaggerated. There is a good deal of mythology in the anecdotes we are offered. It is not altogether clear how the mythology gets established, but it is often repeated, with scant evidence. (pg. 28)
The important point to note here, of course, is the assumption that we have an evolved response to fear snakes (and spiders) based on a minority of actually dangerous species to humans.
The EP enterprise is built on what Gould (1978) termed “just-so stories”, borrowed from Rudyard Kipling’s (1902) book of stories called “Just So Stories” (which he told to his daughter) where he imagined ways that in which certain animals look the way they do today. These stories needed to be told “just so” or she would complain.
And the Camel said ‘Humph!’ again; but no sooner had he said it than he saw his back, that he was so proud of, puffing up and puffing up into a great big lolloping humph.
‘Do you see that?’ said the Djinn. ‘That’s your very own humph that you’ve brought upon your very own self by not working. To-day is Thursday, and you’ve done no work since Monday, when the work began. Now you are going to work.’
‘How can I,’ said the Camel, ‘with this humph on my back?’
‘That’s made a-purpose,’ said the Djinn, ‘all because you missed those three days. You will be able to work now for three days without eating, because you can live on your humph; and don’t you ever say I never did anything for you. Come out of the Desert and go to the Three, and behave. Humph yourself!’ (How the Camel got His Hump)
These stories “sound good” but is there any way to verify these nice-sounding stories? One can then make the same argument for EP hypotheses: can they be independently verified? The thing about functional verification is that we cannot possibly know the EEA of humans—or other animals—and thusly any explanation for the functionality of a certain trait are nothing but just-so stories.
Kaplan (2002: S302) argues that:
Evolutionary psychology has not yet developed the tools necessary to uncover our “shared human nature” (if such there is—see Dupre 1998) any more than physical anthropology has been able to uncover the specifics even of such clear human adaptations as our bipedalism. It is obvious that our brains were subject to selective pressures during our evolutionary history; it is not at all obvious what those pressures were.
I don’t deny that we are the products (partly, natural selection isn’t the only mode of evolution) of evolution; I do deny that these fantasy stories can tell us anything about how and why we evolved though. I don’t see how EP can develop such tools to uncover our “shared human nature”—or any other “nature” for that matter—unless time machines are developed and we can directly observe the evolution of trait X that is being discussed.
A simple argument to show that EP hypotheses are just-so stories:
P1) A just-so story is an ad-hoc hypothesis
P2) A hypothesis is ad-hoc if it’s not independently verified (verified independently of the data the hypothesis purports to explain)
P3) EP hypotheses cannot be independently verified
C) Therefore EP hypotheses are just-so stories
This simple argument shows that all EP hypotheses are just-so stories since they cannot be independently verified of the data they attempt to explain. Stories can “sound good”, they can “sound logical”, they can even be “parsimonious” and they can even be the “inference to the best explanation“, (how do you but just because these stories are “parsimonious”, “sound logical” and are the “inference to best explanation” doesn’t make the stories true. The above argument holds for one of HBD’s pet theories, too, the cold winter theory (CWT). It cannot be independently verified either, and it was formulated after national IQ differences were known; therefore CWT is a just-so story.
(I will cover this more in the future.)
Stories about snakes and spiders in our evolutionary history are likely wrong—especially if they derive from what supposedly occurred in our EEA, an environment we know almost nothing about. The fact of the matter is, regarding snakes and spiders, there is no evidence that our fear of them is an adaptive response to what occurred in our EEA. That is a just-so story. Just-so stories are ad-hoc hypotheses that cannot be independently verified, therefore EP hypotheses are just-so stories.