Popper’s Epistemology and World Three

Abstract

“Much of my work in recent years”, writes Karl Popper, “has been in defence of objectivity, attacking or counterattacking subjectivist positions.” (Popper [1974], 110) Indeed, this is the main thrust of his book Objective Knowledge, in which he develops a theory of three worlds to display the objective character of scientific knowledge. Popper’s view is based on a distinction between knowledge or thought in the subjective sense, which “consists of a state of mind or of consciousness or a disposition to behave or react” (Popper [1975], 108) and knowledge or thought in the objective sense, which “consists of problems, theories, and arguments as such” (ibid., 109). The objective contents of thought belong to world three, while the mental states, events and behavioral dispositions make up world two; world one is reserved for what remains — physical objects, states and processes.

I am greatly indebted to Noretta Koertge for reading an earlier draft of this paper and making helpful suggestions.