Abstract

In the first part of Plato's "Theaetetus" Socrates examines the definition "knowledge is perception". The long and arduous discussion begins with the assumption that knowing and perceiving are the same thing, and it ends with the conclusion that knowing is something completely different from perceiving. In making explicit the implications of Theaetetus' 'first child' Socrates first introduces an account of both perceiving and thinking that amounts to saying that whatever we perceive or think is true. This 'infallibilist' account is true in a world in which everything changes in the way described by what I call the flux-ontology. However, if this account were correct, we would not be agents of our beliefs. Our beliefs would instead be things that happen to us. Without being rational, active agents of our process of forming beliefs, we would not be able to justify, to correct, and to discuss our beliefs. In his analysis of "perceiving" and "grasping being and truth", Socrates then puts things right by showing that our capacity of perceiving in the broader sense of the word is intrinsically judgmental. The upshot of the first main part of the "Theaetetus" can be understood as Plato's discovery of the propositional nature of perceiving