摘要：In the argument on “things that both are and are not” (R.V476a1-479b10) I distinguish “communion” (koinônia:476a8) from “participation” (methexis:478d1-3) arguing that while one explains how the many things participate in Forms, the other focuses on how opposite Forms commune in the multiplicity of their instances. Opposing “what is” to “what is not” and equating them with “what can and cannot be known” the argument introduces an alternativebetweenthem: “that which is and is not”, thus distinguishing three cognitive faculties: knowledge, ignorance and opinion. The objects of the first two are easily recognized, however it seems problematic to point to what kind of things “are and are not”. Socrates then proposes that these correspond to the multiplicity of the “beautiful, just, or pious” things for there is not a single one of them that will not seem “ugly, unjust and impious”, due to the communion of opposite Forms in them. This argument is later (523a-524c) justified by an analysis on how by being perceived through a single sense organ sense-perception confounds opposing sensations.
