Ockham was a Franciscan friar who studied at Oxford and developed a philosophy of radical economy. His famous razor (entities must not be multiplied beyond necessity) was a weapon against the elaborate metaphysical systems of his predecessors. He argued that universals are mental constructs, not real things. Summoned to Avignon on charges of heresy, he fled to Munich under the protection of Emperor Ludwig IV. He spent the rest of his life writing on politics and logic. His nominalism influenced the entire trajectory of modern philosophy and science.
Entered the Franciscan order as a boy and studied theology at Oxford. He never completed his master's degree, earning the title 'Venerable Inceptor' instead of full professor. His lectures on logic and metaphysics were already making waves.