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Why does evidence of biological influences on behavior not determine moral rules or public policy?

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Marble bust of Aristotle with a beard and draped robe, showing detailed facial features and wavy hair, set against a dark background. — Philosophy of biology Detail of a Roman copy (2nd century bce) of a Greek alabaster portrait bust of Aristotle, c. 325 bce; in the collection of the Roman National Museum.

In the philosophy of biology, evidence of biological influences on behavior does not dictate moral rules or public policy primarily because of the logical distinction between factual observations and moral obligations.

The Naturalistic Fallacy

Philosophers, most notably G.E. Moore, have argued that attempting to derive moral "oughts" from natural "is" statements constitutes the naturalistic fallacy. This concept, rooted in the work of David Hume, highlights that facts about human evolution or biology do not inherently possess moral authority. Simply because a behavior is natural or has an evolutionary basis does not make it rational, correct, or morally desirable.12

Limitations of Biological Determinism

The assumption that biological traits are fixed or dictate social outcomes—often termed biological determinism—has historically been used to justify discriminatory policies, such as the eugenics movement. However, modern science demonstrates that the relationship between genotype and phenotype is highly complex and influenced by environmental factors. Because genes are not destiny, biological data cannot serve as a rigid foundation for social or ethical mandates. Ethical principles must be grounded in rational deliberation rather than the mere observation of biological processes.31