Plato and Aristotle were influential ancient Greek philosophers. Plato founded the Academy in Athens, where he taught subjects like geometry. He was influenced by his teacher Socrates and wrote dialogues like The Apology describing Socrates' trial. Aristotle was a student of Plato's and founded his own school, the Lyceum. He tutored Alexander the Great and made contributions to fields like biology, causality, and different types of scholarly works. Both Plato and Aristotle employed methods like proofs by contradiction and remain hugely influential philosophers.