Mathematician:Aristotle

Aristotle (Greek: Ἀριστοτέλης, Aristotélēs) was a Greek philosopher, a student of Plato and teacher of Alexander the Great.

Phenomenally influential philosopher whose works (for better or for worse) shaped the entirety of the intellectual development of the Western world for over a millennium.

Most important from the point of view of mathematics for formulating the Principle of Non-Contradiction and the Law of the Excluded Middle.

Nationality
Greek

History

 * Born: 384 B.C.E., Stagirus, Macedonia, Greece
 * Died: 322 B.C.E., Chalcis, Euboea, Greece

Theorems and Definitions

 * Aristotelian Logic:
 * Principle of Non-Contradiction
 * Law of the Excluded Middle

Writings
Only about a third of his writings survive.