William of Ockham

The principle later called Ockham's razor says that explanations should not multiply entities beyond necessity. William of Ockham did not coin the modern label, but his 14th-century logic and theology made the idea famous.

Ockham is known for nominalism, the view that universals such as humanity or redness are not extra things existing apart from particular humans or red objects. This made him a major figure in medieval debates over language, thought, and reality.

Ockham became involved in disputes over Franciscan poverty and papal authority in the 1320s. He eventually sided with critics of Pope John XXII and took refuge under Emperor Louis IV.

Summa Logicae is one of Ockham's major works on terms, propositions, and inference. It is a central text for understanding 14th-century scholastic logic.