The belief that any given structure, which we think, often erroneously, would have been beneficial to a species, would have been gained under all circumstances through natural selection, is opposed to what we can understand of its manner of action.
Guk espeziearentzat onuragarri izanen zela, maiz oker baina, uste dugun zeinahi egitura, hautespen naturalaren bidez edozein zirkunstantziatan nahitaez erdietsi behar zela dioen eritzia, haren jokamoldeaz uler dezakegunaren kontrakoa da.