I have only the most superficial familiarity with Plato, but here's my guess: #1 is Plato. It expresses a clear theme that happens to match my vague understand

I have only the most superficial familiarity with Plato, but here's my guess: #1 is Plato. It expresses a clear theme that happens to match my vague understanding of what "Platonism" is, and the writing is efficient and effective. The metaphor of knowledge as "food" seems particularly unlikely to be something that GPT-3 would express in such a concise way. The only thing that really gives me pause is the part at the end about "the revolution of the worlds"; I'm not sure what exactly that's referring to. #2 is GPT-3. The topic meanders a lot, and there are a lot of individual chunks of prose that sound weird to me, or at least artless. (What value is "as I dare say you yourself know" adding, for instance?) It seems to be throwing around words like "beauty", "mind", "soul" and "wisdom" in ways that obscure their meanings, rather than elucidating them. For example, "wisdom [...] is the pilot of the soul" makes much less sense than "mind, the pilot of the soul".