Perception and Judgment in the Theaetetus

Abstract

In the Theaetetus, Plato argues against the thesis that knowledge is perception. At various points in the discussion, one glimpses a background theory of perception which, if fully articulated, would make the course of the argument more intelligible. This is particularly true of the final argument against this thesis at 184-186, for in making this argument Plato seems to speak in his own voice and to make claims about perception that stand in need of further elucidation. Certain features of the argument at 184-186 that bear on the question of what Plato thinks perception is have been discussed by Cooper and Burnyeat with considerable insight.' A full-scale reconstruction of the theory of perception which Plato subscribes to in the Theaetetus remains to be undertaken. Since the Theaetetus is an important source of information about Plato's views on perception in the later period, an attempt at such a reconstruction appears in order. The object of this paper is to carry out this project, i.e., to elucidate the theory of perception found in the Theaetetus. In the first section, a general characterization of perception will be given that meets the requirement that the claims made about perception in the course of the argument at 184-6 are entailed by it. This requirement, it will be argued, would be met by a modified version of the secret doctrine account of perception. The objective of the second section will be to decide whether, on the theory of perception at work in the Theaetetus, human percipients are able to make simple judgments through perception. The third section seeks to give an account of the mind's inability to grasp ousia (being) through perception which is compatible with the position that some simple judgments are made through perception.