A Flaw in Evolutionary Psychology

September 2, 2010

Imagine entering a toy factory, walking up to the assembly line, and observing the first ten toys to be colored red.  You would clearly be epistemically justified—indeed, obligated—to hold the belief that the toys were, in fact, red on the basis of how they appeared to you.  But now imagine that upon entering the factory, you were told that the lighting, combined with the glasses you were required to wear, make all the toys appear red to observers.  And sure enough, the first ten look red to you.  Could they actually be red?  Yes, but now you have a significant defeater for the belief that they are red because of how they appear to you.  The problem is this:  You would have the experience of redness and form the associated perceptual belief regardless of whether or not the toys were red, so the truth of the matter would be irrelevant to your belief formation.

Rather extravagant claims are being made today by evolutionary psychologists.  From behaviors such as sexual preference to crying, to belief formation/contents such as moral views, the argument is made that we engage or possess such because the associated behaviors, and the mechanisms underlying them, conferred some evolutionary advantage on our ancestors.  Unfortunately, such explanations can be used to “justify” rape or practically any behavior (by arguing that these tendencies are normal due to the fact that they must have conferred advantage on our ancestors, or else they wouldn’t be here now).  To avoid these implications, some evolutionary psychologists have tried to argue that evolution selected behaviors that are altruistic, not “deviant”, so the former are normal, not the latter.

But all this is fundamentally wrong-headed.  For one thing, even if we grant this counter-argument, it is a contingent fact about evolution, and there are possible worlds in which evolutionary psychology “justifies” rape. Further, “deviant’ is not a normative notion, but a merely statistical or survival-enhancing notion, and each is merely descriptive, not prescriptive.

But there is a more fundamental flaw with evolutionary psychology.  It provides a toy-factory defeater for morality itself.  Why?  Because given its approach to things, homo sapiens would have the moral beliefs/behaviors they have whether or not they were true.  And given a naturalist background, it is opaque as to how one could claim that our moral belief/behaviors formed in the struggle for survival, somehow correspond to some sort of moral realm of non-physical facts.  The same line of argument can be advanced regarding the implications of evolutionary psychology for rationality itself.  I have addressed this in the appendix of my book The Recalcitrant Imago Dei, but basically the idea is that our cognitive faculties (senses/intellect) would form the experiences/beliefs they do whether or not they were accurate or true.  Why?  Because the mechanisms that are employed to form these beliefs/experiences function at they do with respect to the evolutionary advantage the conferred on our ancestors, not with respect to whether or not they matched facts in some external world.  And it is hard to see how something so magnificent as our rational faculties could simply be a mere spandrel.  If I am right about this, then the entire approach of evolutionary explanation is fundamentally flawed and self-refuting.


About J.P. Moreland

J.P. Moreland is the Distinguished Professor of Philosophy at Biola University.

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3 Responses to 'A Flaw in Evolutionary Psychology'

  1. avatar Jeff Kennedy says:

    Hi Dr. Moreland. I am a Doctoral Student at Talbot and have a question related to your post here. You stated,
    “Because given its approach to things, homo sapiens would have the moral beliefs/behaviors they have whether or not they were true”

    This is a good explanation for why evolutionary morality cannot be truly objective, but my question is: Since objective morality cannot come from a purely natural and undirected process, why couldn’t objective morality be an abstract reality e.g. math and logic? Why does objective morality have to be grounded in a personal God? What do we say to the skeptic who charges us with denying Okham’s razor of multiplying causes beyond necessity? Why is a personal God the necessary foundation of these values instead of the independent existence of them?
    Hope that makes sense.
    Thanks you for your ministry.
    Pastor Jeff

  2. avatar Daniel says:

    Hi Mr. Moreland.

    Great stuff!

    And many good writings you have made here on the site…

    Wish we would have some great apologetics here in Denmark to, but Northern Europe do sadly enough don’t have a tradition for fostering christian philosophers or apologetics. So it is truly a great help i can go places like this to look for information. 🙂