1.7 Levels of explanation and common misunderstandings

Evolutionary psychology is more misunderstood than almost any field. Most objections target claims the field does not make. Clearing them away is essential before going further.

Proximate vs. ultimate causes

Every behavior has two complementary explanations. A proximate explanation describes the immediate machinery — hormones, neurons, learning, stimuli. An ultimate explanation describes the evolutionary function — why selection built that machinery. "A mother loves her baby because of oxytocin" and "because caring for offspring propagated her genes" are both true; they answer different questions and do not compete.

The naturalistic fallacy

The naturalistic fallacy is the error of inferring ought from is — assuming that whatever evolved is therefore good or justified. Evolution explains why infanticide, deception, and violence exist under certain conditions; it never endorses them. Describing a tendency is not approving of it. Understanding a disease is the first step to curing it.

Genetic determinism is not the claim

Saying a trait is an adaptation does not mean it is fixed, inevitable, or unchangeable. Adaptations are typically conditional — they produce different outputs depending on environmental inputs. Calluses are an adaptation, but you only grow them where there is friction. Most evolved psychology works the same way: if-then programs sensitive to context.

A grounding example

Consider the claim that men are, on average, more physically aggressive than women. The naturalistic fallacy would (wrongly) conclude that male violence is therefore acceptable. Genetic determinism would (wrongly) conclude that nothing can change it. The correct evolutionary reading is conditional: aggression is a strategy that paid off for ancestral males under specific circumstances (competition for status and mates), and rates vary enormously with context — which is exactly why societies that reduce those incentives see far less violence.