Testing the theory of forms › Which things have Forms?

Parmenides first probes the scope of Socrates' distinction. Socrates accepts Forms of justice, beauty and goodness. He is unsure about a separate Form of a human being, fire or water. Asked about hair, mud and dirt, he resists, though he admits being troubled by the possibility that the same reasoning might apply to everything. Parmenides connects this resistance with Socrates' youth and concern for ordinary opinions (130b–e).

The philosophical issue is a demand for a reasoned boundary. If a Form explains what many instances share, why should an unglamorous subject be excluded simply because it seems beneath philosophy? That question does not itself prove that every word has a corresponding Form. A defender might distinguish independently grounded properties or kinds from arbitrary classifications. The point is that dislike or embarrassment cannot do that classificatory work by themselves.

Consider a modern analogy. An organization may want a precise account of excellence but avoid defining what counts as routine failure because the subject feels embarrassing. That preference does not show that failures lack an intelligible structure. The comparison concerns consistency in inquiry. It does not identify organizational categories with Platonic Forms or settle which categories deserve independent metaphysical status.

The scope question also teaches a reading habit. Before asking whether a theory is true, ask what its proponent intends it to cover. An objection to a claim about every shared characteristic may miss a theory restricted to certain kinds. Conversely, restricting the theory only after an awkward example appears can leave the explanatory boundary arbitrary.