The naturalistic fallacy is the error of deriving moral conclusions from factual premises—of inferring what ought to be from what is. If evolution shaped humans to seek status, it does not follow that status-seeking is morally good. If humans have aggressive impulses, it does not follow that aggression is justified. The fallacy confuses description with prescription.1
This fallacy haunts evolutionary psychology: explaining human behavior through evolution risks sounding like justifying that behavior. If male sexual jealousy is an evolved response to paternity uncertainty, does that make jealous surveillance of partners acceptable? If status competition is evolved, does that justify ruthless dominance-seeking?2
The critical move is distinguishing between explaining why humans do something and justifying whether they should. These are completely independent. You can explain human cruelty through evolutionary selection (people who were cruel to outgroups reproduced more successfully) without concluding that cruelty is justified.3
Evolutionary psychology explains the origin of human motivations and psychology. It does not establish their moral status. Understanding that guilt evolved as a commitment device does not make guilt obligatory or good—it just explains why we feel it.4
Yet there's a deeper problem: if all moral sentiments evolved for reproductive success rather than for accessing moral truth, does that debunk morality? If our conviction that cruelty is wrong evolved because cruelty-opposed individuals were better cooperators, is that conviction merely an illusion?5
Wright argues for what might be called evolutionary grounding rather than evolutionary debunking: yes, moral sentiments evolved, but that doesn't make them false. It explains why morality exists and why it matters to us. The fact that empathy evolved doesn't make empathy less real; it explains why we're equipped to be moral creatures.6
Philosophers vs. Evolutionary Debunkers on Moral Reality
Moral philosophers (especially realists) argue that moral truths exist independent of human belief. Cruelty is wrong not because we evolved to think it's wrong, but because it really is wrong.7
Evolutionary debunkers argue that if morality evolved for reproductive success, moral beliefs are illusions—they're just adaptive fictions that happen to feel true.8
Wright suggests a middle position: morality is real but grounded in evolved sentiment rather than in transcendent principles. What makes something morally significant is that humans (with their evolved moral equipment) care about it. This grounds morality without requiring either transcendence or debunking.9
The naturalistic fallacy arises because philosophy assumes moral facts must be either transcendent (independent of human nature) or illusory. Evolutionary psychology reveals a third option: moral facts can be grounded in evolved human nature without being illusory.10
What makes suffering morally significant is not that suffering exists in some abstract moral realm, but that humans are constituted to care about suffering. The caring is real; the significance is real; the grounding is evolutionary.11
The handshake is that understanding evolution's role in moral psychology doesn't require abandoning moral realism—it relocates the ground of morality from transcendence to human nature, which is perfectly stable and perfectly real.12
If the naturalistic fallacy is real—if explaining a behavior's origin doesn't justify it—then explaining human nature through evolution provides neither moral absolution nor moral condemnation. You cannot say "male sexual jealousy is wrong because it's evolved" (that commits the fallacy), but neither can you say "male sexual jealousy is justified because it's evolved" (also the fallacy).13
What you can say: evolved jealousy is real, powerful, and shaped by selection. Whether it's good requires separate moral argument. Understanding its origin illuminates the conversation but doesn't resolve it.14