 Later Platonists naturally understood Parmenides as thus anticipating Plato, for Plato himself seems to have adopted a “Platonist” understanding of this thinker whose influence on his own philosophy was every bit as profound as that of Socrates and the Pythagoreans. Aristotle attributes to both Parmenides and Plato the recognition that knowledge requires as its objects certain natures or entities not susceptible to change—to Parmenides in De Caelo 3.1, and to Plato, in remarkably similar language, in Metaphysics 13.4. The arguments at the end of Republic 5 that confirm Aristotle’s attribution of this line of reasoning to Plato are in fact suffused with echoes of Parmenides. Plato likewise has his fictionalized Parmenides present something very close to this line of argument in the dialogue bearing his name: “if someone will not admit that there are general kinds of entities…and will not specify some form for each individual thing, he will have nowhere to turn his intellect, since he does not admit that there is a character for each of the things that are that is always the same, and in this manner he will destroy the possibility of discourse altogether” (Prm. 135b5-c2). The Platonic “natures” Aristotle has in mind are clearly the Forms that Plato himself is prone to describing in language that echoes the attributes of Parmenidean Being, most notably at Symposium 210e-211b and Phaedo 78d and 80b. That Plato’s Forms are made to look like a plurality of Parmenidean Beings might seem to supply Platonic authority for the meta-principle interpretation. This would be a rash conclusion, however, for Plato consistently represents Parmenides as a monist in later dialogues (see, e.g., Prm. 128a8-b1, d1, Tht. 180e2–4, 183e3–4, Sph. 242d6, 244b6). Determining just what type of monism Plato means to attribute to Parmenides in these dialogues ultimately requires plunging into the intricacies of the examination of Parmenides’ thesis in the latter part of the Parmenides.