Aristotle was, as Marx and many others have said, the greatest philosopher of antiquity. In opposition to Plato, who was the quintessential idealist philosopher, Aristotle had a much more down-to-earth approach; a much more empirical, or investigative approach to knowledge. However, that does not mean that he was always right about everything he said! As one little example, he claimed that women have fewer teeth than men, which no doubt was a quite satisfying conclusion for a product of a male-run noble class concerned to prove the inferiority of women and slaves. Exactly how Aristotle came to his conclusion that women have fewer teeth than men, I don't know. But perhaps it was like this: