A major problem with the Stoned Ape Hypothesis for me is that it lacks any physical mechanism. It's fair enough to argue that psychedelics might increase some c

A major problem with the Stoned Ape Hypothesis for me is that it lacks any physical mechanism. It's fair enough to argue that psychedelics might increase some cognitive or perceptual faculties, but McKenna never explains how this could lead to a selection pressure for intelligence, or any other mechanism for genetic alteration.