Aristotle in Metaphysics: To say of what is, that it is, or of what is not, that it is not, is true .

To say of what is, that it is, or of what is not, that it is not, is true . — Aristotle in Metaphysics

To say of what is, that it is, or of what is not, that it is not, is true .

Aristotle in Metaphysics

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