Against Evolutionary Psychology

Scientism – the slightly-smarter, yet irrevocably ignorant brother of Theism. The epistemic conviction of science as the only tool for discerning truth infuriates me. Especially when the former is employed in moral and psychological realms, the theory of evolution explaining behavioral traits, and its prevalent universal acceptance. Here, I make a case against evolutionary psychology, revealing the incoherence of the framework itself1.


Similar to other biologically informed approaches to human behavior, evolutionary psychology works on the assumption that all human behavior can be explained by appealing to internal psychological mechanisms2. The difference is the postulate that these internal mechanisms are adaptions, products of natural selection that helped our ancestors survive and reproduce.

In Neurocognitive Adaptations Designed for Social Exchange3, the authors establish the basic tenets of the field.

  1. The brain is a computer designed by natural selection to extract information from the environment.
  2. Individual human behavior is generated by this evolved computer in response to information it extracts from the environment. Understanding behavior requires articulating the cognitive programs that generate the behavior.
  3. The cognitive programs of the human brain are adaptations. They exist because they produced behavior in our ancestors that enabled them to survive and reproduce.
  4. The cognitive programs of the human brain may not be adaptive now; they were adaptive in ancestral environments.
  5. Natural selection ensures that the brain is composed of many different special-purpose programs and not a domain general architecture.
  6. Describing the evolved computational architecture of our brains “allows a systematic understanding of cultural and social phenomena”

Argument contra Fitness Function

Natural Selection is grounded on the existence of the Fitness Function. It is the metric that denotes the ability of an organism to survive and reproduce, relative to its environment. For our proponents, the adaptions themselves are a response to increasing fitness function. However, a glaring problem exists when humans are the focus of such an analysis.

P1. Humans don’t abide by the fitness function

Humans, perhaps for thousands of years, haven’t abided by an evolutionary optimal fitness function, one that prioritizes survival and reproduction, under intentional knowledge of this sub-optimality. Incestuous Courtships, Inter-Caste Marriages, Marriages of State4 are widespread historical examples. It’s clear that for a significant portion of human history, reproduction wasn’t determined by evolutionary mechanisms.

P2. Adaptiveness implies Selection

Postulate (4) above bypasses the contention through the claim that adaptive traits exist that are not under natural selection now. Then there must exist a point in history where selection ended for humans. Assuming human behavior can be explained, in its entirety, by adaptive behaviors, and historical evidence aligns with non-adaptive behaviors, a contradiction is posed. For if selection ended, leaving remnants of those last adaptive behaviors, we must have acted on their basis – contrary to the evidence.

Conclusion: Human Behavior cannot be explained, in its entirety, by Evolutionary Psychology

Considering that the fitness functions hold no relevance to human behavior, and the alternative explanation of adaptation without selection contradicting itself – it’s safe to conclude the incorrect nature of evolutionary psychology.

  1. As opposed to a metaphysical contention against physicalism, which has to be assumed for this to work
  2. Downes, S. M. (2018, September 5). Evolutionary psychology. Stanford Encyclopedia of Philosophy. Retrieved March 27, 2023, from
  3. Cosmides, L. and J. Tooby, 2005, “Neurocognitive Adaptations Designed for Social Exchange”, in The Handbook of Evolutionary Psychology, D. Buss (ed.), Hoboken, NJ: Wiley, pp. 584–627.
  4. Wikimedia Foundation. (2022, November 5). Marriage of State. Wikipedia. Retrieved March 27, 2023, from

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