Begging the question (petitio principii)

Biological Parallel

'Why do organisms have adaptations? Because natural selection produces adaptive traits.' This begs the question—assumes what needs proving (that traits are adaptive). The circular reasoning: organisms survive because they're fit; we know they're fit because they survived. Evolutionary biology battles this constantly: post-hoc adaptive storytelling assumes every trait is optimal. The antidote: test alternative hypotheses (neutral evolution, historical constraint, byproduct). Circularity masquerading as explanation.