Popper's three?world doctrine differs significantly from an earlier position which insisted on a dualism of facts and norms. This dualism, combined with a hostility to that version of psychologism which holds that logical principles are descriptive psychological laws, initially led him to espouse the view that we are free to reject rules of inference as norms shaping our reasoning. However, in some formulations of his recently developed pluralistic epistemology, Popper appears to deny this freedom to the individual. Feyerabend has condemned (...) him for this. My critique conflicts with Feyerabend's, in that I develop an alternative view of the relationship between logic and psychology which retains the compulsive aspect of the third realm, but rejects that version of anti?psychologism which holds that truths of logic do not have normative implications for people's psychological states. More specifically, it is argued that it is logically possible, though logically impermissible, for people to be irrational: the categories of logic are inescapably evaluative and critical. (shrink)