Maybe we over simplify Plato’s’ meaning here, and if not, then so be it because hot and cold are perceptions only having little to do with any ‘single reality’ viewpoint. The truth is this….”there are only varying states of hot” since everything (mass) radiates energy (heat) and the lack of this energy (absolute zero or .3 above it) converts mass into something that defies rational description….
The point of Plato’s observation has nothing to do with “varying states of hot.” He might have been referring to water at the boiling point and freezing point (absolute zero wasn’t known at that time) trying to define “the real.” How cold or hot something was is not paramount. Plato discovered that Reality had to be compatible with both cold and hot yet could not be identified with either, which would negate the other, or even both at the same time because hot-cold would be a contradiction. He speaks of “unity” as defined as without parts. It can’t have boundaries. The word used by St. Thomas Aquinas is “simplicity.” So, from what I read, it appears that Plato found a way for explaining the apparent unity of opposites manifested in quantum physics.
Secondly, it seems (and I found support for this) that Plato’s’ argument jumps from deductive reasoning to inductive support (reasoning) arguing existence/creation and the ideals of a creator of the universe and it is this paradox that most arguments (one way or the other) stem.
But Socrates has students who were zealous in their careful reporting as Jesus had apostles and disciples who also were faithful to His teachings writing them down for posterity. (I really don’t know about Plato’s teacher, but it’s non-essential to the argument anyway).
I don’t know if anyone else on this thread considers Reality a definite in philosophy, but the word Reality points to that which
is, that which is true, that which is unbounded or independent.
The dictionary definition is as follows:
Philosophy (of the word "Reality)
a. something that exists independently of ideas concerning it.
b. something that exists independently of all other things and from which all other things derive.