Aristotle on identity: close enough!

We present what Aristotle wrote on identity in a leisurely manner, which is much more than is generally known, save among the cognoscenti (Aristotle scholars), and mutatis mutandis about the introduction of the identity-symbol [Formula: see text]. We add two codas, one on the so-called Leibniz' Law, which is different (but resembles) what passes for it in logic and philosophy, and one on the status of identity, as accepted by mathematicians and logicians, in physics. This article is part of the theme issue 'Identity, individuality and indistinguishability in physics and mathematics'.