Aristotle
- Metaphysics: Book I, 987a13-19: "The Pythagoreans, while they likewise spoke of two principles, made this further addition, which is..."
- Metaphysics: Book XIV, 1090a20-5: "The Pythagoreans, on the other hand, observing that many attributes of numbers apply to sensible..."
Aristotle (384 – 322 BCE) was a Greek philosopher, student of Plato and Socrates, and tutor to Alexander the Great. His writings cover many topics, and constitute the first comprehensive system of Western philosophy. His system of syllogistic logic provides the earliest example of the Law of the Excluded Middle, a foundational principle in modern jurisprudence.