From DC Lau’s introduction to bjs translation of the Lao Tzu:
According to Plato, the objects of the sensible world are unreal to the extent that it can be said, at the same time, of any one of them that it is both A and not-A.
…
Again, Plato's insistence that of anything real we must be able to make a statement to the exclusion of its contradictory seems to stem from his assumption that the totally real must be totally knowable.
It actually did not occur to me before that to say that something is both A and not A, where A is some aspect like being round, you do have to know that something completely.
I think at this point, we have to accept that
completely knowing a thing is out of reach.