Essence

The what-it-was-to-be

Aristotle’s strange phrase to ti ēn einai, “the what-it-was-to-be,” names the essence of a thing: what it is in itself, as against its incidental features. Essence is what a real definition captures, and Aristotle binds it closely to substance and to form — a thing’s essence is its form, the intelligible nature that makes it the kind of thing it is and grounds all else true of it.