From the Beginning to Plato

FROM THE BEGINNING TO PLATO 353
that Forms are the sole objects of knowledge, where knowledge must be
contrasted with judgement, not explained in terms of it. After all, it is clear that
the Theaetetus cannot represent Plato’s abandonment of his earlier view, given
that later dialogues are still emphatically contrasting perception and judgement
(doxa) with knowledge on the basis of a difference in their objects. Thus, the
Timaeus (27d–28a, 51d–51a) asserts: Being (i.e. Forms) is grasped by
intelligence (noēsis) with an account (or reason, logos), while becoming (the
sensible world) is grasped by judgement (doxa) with perception. Yet, in direct
contradiction of this, the Theaetetus considers definitions of knowledge that state
that it is perception or a kind of judgement (doxa). So, perhaps, Plato takes the
Theaetetus’ failure as confirmation of the Timaeus’ view on the objects of
knowledge.
But this interpretation faces serious problems, the answers to which are far
from clear. For example: why should the difficulties which afflict proposed
definitions of knowledge in terms of judgement (doxa) disappear when
knowledge is defined as a kind of thought (noēsis)?
Lacking the notions of proposition and sense, Plato can only identify the
contents of thought with beings—facts or objects—in the world. Taking
statements to name facts in the way that words name objects, Plato is inclined to
construe stating or judging what is false as stating or judging where there is no
content to be stated or judged. False judgement appears impossible.
Likewise, for Plato, if I think of X I am thereby related to a being in the world
which is the content of the thought. And how could I think of X—that being
which furnishes the content of my thought— if I was not aware of X, if I did not
know X? And if I know Y as well as X, I would never say to myself that X is Y,
i.e., I could not judge falsely that X=Y. While if Y is unknown to me it could
never enter into any judgement I made, so again I could not falsely judge that
X=Y.
These problems from the Theaetetus are attacked with the wax tablet and
aviary models, which begin to make headway towards over-coming some of the
obstacles to an account of false judgement in so far as they provide for the
possibility of an object entering into thought via different routes. But it is the
Sophist which presents Plato’s solution, 66 a solution which does not build on the
Theaetetus.
The main philosophical section of the Sophist begins with the assertion that in
order to show how false judgement is possible, Parmenides’ assertion ‘Never shall
this be proved, that things that are not are’ must be refuted. For a false statement
says that what is not (=Not Being) is.
The main point needed to overcome Parmenides’ dictum is that ‘Not Being’ or
‘What is Not’ does not signify contrary to being, i.e. non-existence, but different
from being. Focusing on the ‘greatest Kinds’—Being, Difference, Sameness,
Rest and Motion—Plato, after explaining how some can participate in and hence
be the others, points out that each is different from the others, and hence can be
said to not be each of the others. So Not Being exists.