Note Footnote 4: — INTRODUCTION.
Reading edition
Incidentally in discussing the Axiom of Contradiction (ἀξίωμα τἢς ἀντιφάσεως),4 Aristotle lays down what is now known as the Law of Excluded Middle. Of two contradictories one or other must be true: we must either affirm or deny any one thing of any other: no mean or middle is possible.