The Theory that Perception is Knowledge

David Bostock

in Plato’s Theaetetus

Published in print February 1991 | ISBN: 9780198239307
Published online October 2011 | e-ISBN: 9780191679889 | DOI:

Series: Clarendon Paperbacks

The Theory that Perception is Knowledge

Show Summary Details


This chapter analyzes the theory that perception is knowledge. begins by introducing Protagoras and his thesis that all perceptual judgements are true, and it is apparently indicated that this thesis will be defended by stressing the relativity of perception: the wind may perhaps feel hot to you and cold to me, in which case we shall say that it is hot to you and cold to me, and we shall not allow that it is either hot or cold ‘in itself’. Then at once we get the first statement of the ‘secret doctrine’, stated as the doctrine that nothing ever is, but is always coming to be, and that the things that we ordinarily say are in fact come to be from motion, change, and mixture: they are the offspring of flux and change (152d–e). Taking this together with the later statement that only changes exist (156a), and using what we know of the further development of the theory, we can see that the doctrine intended must be this: the only things that exist in their own right are changes — that is, comings-to-be, happenings, or events — and what we ordinarily regard as persisting things are in fact just series or collections of these changes.

Keywords: secret doctrine; happenings; Protagoras; Heraclitus; perception; knowledge

Chapter.  19615 words. 

Subjects: Ancient Philosophy

Full text: subscription required

How to subscribe Recommend to my Librarian

Buy this work at Oxford University Press »

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.