[55] Plato, Sophist. p. 251 E.
No intercommunion between any distinct forms. Refuted. Common speech is inconsistent with this hypothesis.
If we take the first alternative — that there is no intercommunion of Forms — then the Forms motion and rest can have no intercommunion with the Forms, essence or reality. In other words, neither motion nor rest exist: and thus the theory both of those who say that all things are in perpetual movement, and of those who say that all things are in perpetual rest, becomes unfounded and impossible. Besides, these very men, who deny all intercommunion of Forms, are obliged to admit it implicitly and involuntarily in their common forms of speech. They cannot carry on a conversation without it, and they thus serve as a perpetual refutation of their own doctrine.[56]
[56] Plato, Sophist. p. 252 D.
Reciprocal intercommunion of all Forms — inadmissible.
The second alternative — that all Forms may enter into communion with each other — is also easily refuted. If this were true, motion and rest might be put together: motion would be at rest, and rest would be in motion — which is absurd. These and other forms are contrary to each other. They reciprocally exclude and repudiate all intercommunion.[57]
[57] Plato, Sophist. p. 252 E.
Some Forms admit of intercommunion, others not. This is the only admissible doctrine. Analogy of letters and syllables.
Remains only the third alternative — that some forms admit of intercommunion — others not. This is the real truth (says the Eleate). So it stands in regard to letters and words in language: some letters come together in words frequently and conveniently — others rarely and awkwardly — others never do nor ever can come together. The same with the combination of sounds to obtain music. It requires skill and art to determine which of these combinations are admissible.
Art and skill are required to distinguish what Forms admit of intercommunion, and what Forms do not. This is the special intelligence of the Philosopher, who lives in the bright region of Ens: the Sophist lives in the darkness of Non-Ens.