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How did Plato distinguish between affirmation and negation?

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Marble bust of Aristotle with a beard and draped robe, showing detailed facial features and wavy hair, set against a dark background. — Applied logic Aristotle, marble portrait bust, Roman copy (2nd century bce) of a Greek original (c. 325 bce); in the Museo Nazionale Romano, Rome.

In his dialogue the Sophist, Plato distinguished between affirmation and negation by moving away from the idea that negation implies absolute "not-being," which had previously created logical antinomies.12

Instead, Plato argued that a negative assertion of the form "A is not B" should be understood as having the force that A is "other" than B. By interpreting negation as a statement of difference (heteron) rather than a claim of non-existence, he resolved the conflict between Being and Not-Being.21

This analysis was supported by his structural breakdown of language, where he distinguished between names (nouns and adjectives) and verbs. He posited that a complete statement (logos) requires at least one of each, as a sequence of only names or only verbs cannot form a proposition capable of being true or false. This distinction allowed for a more sophisticated understanding of predication, providing a foundation for the logical analysis of statements that would be further developed by his pupil, Aristotle.34