Compresence of Opposites

Here's an interesting passage by a scholar writing on whether Plato accepted some doctrine of the "Compresence of Opposites" in sensible particulars, and, if so, what that doctrine is best taken to mean.

He considers the following version of that doctrine:

For any property F that admits a contrary (con-F), all sensible F things are con-F.

And he argues as follows that Republic book V gives no support for the doctrine so formulated:

[Someone might claim] to find direct evidence for this principle in Republic 5's description of "the many beautiful things," on which the sight-lovers focus their attention, as also appearing ugly (479a-b), [if we take] these many beautiful things to be particular objects. [But to do so would be to fail] to notice ... that when the sight-lovers are introduced as accepting "beautiful things" (kala pragmata) but not beauty itself (476c1-3), these are the "beautiful sounds, colors, shapes, and all the things fashioned from these" the sight-lovers have just been said to enjoy (476b4-6). It is surely no accident that the same properties the Phaedo's Socrates can no longer accept as making things beautiful recur so prominently here.

The author then concludes that the above formulation of Compresence of Opposites should be rejected "in favor of the more philosophically sophisticated interpretation ... developed by Terence Irwin."

Now it would be too easy to deal with this argument by saying that, since it defers to a particular interpretation of the Phaedo, it has no more weight than the "Forms as Properties" interpretation of the relevant passage in the Phaedo -- that is, apparently no weight at all.

One might also point out that, of course, even if the argument were successful, to remove one reason in favor of a certain formulation of Copresence of Opposites would hardly be to remove all reasons (not even all the reasons in the Republic), when the author has said nothing to indicate that all of the evidence can be dealt with in this way. (And we shouldn't expect that it could, because not all the evidence is going to have a verbal resemblance to certain lines in the Phaedo.)

And one might wish to put aside, too, the question of whether the 'argument' is not really an argument but another appeal to authority, as perhaps having too obvious an answer to be interesting.

Rather, I'm concerned with two other matters, which I'll discuss later:

--How sound is this scholar's point about the words of that passage from the Republic? and,

--Exactly what is the alternative version of Compresence of Opposites offered by Irwin: is it more 'philosophically sophisticated', and does it capture better what Plato meant?