William of Ockham

Ockham was a Franciscan working within Latin Catholic scholasticism, though his nominalism and divine voluntarism worked against the Thomist consensus.

"Entia non sunt multiplicanda praeter necessitatem." (The Razor, paraphrased; Ockham's actual formulation: "Plurality is not to be posited without necessity")

Ockham's nominalism is the proximate ancestor of British empiricism — only individuals exist, knowledge begins with the apprehension of particulars.

"Nothing can be known naturally that is not derived from sense experience or principles known per se." (Quodlibetal Questions)

Anachronistic as a confessional label, but Ockham's divine voluntarism — moral law as what God wills — is the proximate ancestor of late-medieval and Reformation voluntarist theology that flowed into Luther and Calvin.

"God by His absolute power can do anything that does not involve a contradiction." (Ordinatio, on potentia absoluta vs potentia ordinata)

Ockham's nominalism — only individuals exist, universals are products of intellectual operations — is a foundational ancestor of analytic philosophy of language and ontology.

"All universals are products of intellectual operations." (Summa Logicae)

A working methodological naturalism within scholasticism — natural philosophy is to be done with the fewest theoretical commitments compatible with the evidence.

"It is futile to do with more what can be done with less." (Summa Logicae I.12, paraphrasing the razor)

Luther studied under Gabriel Biel, who was a faithful Ockhamist; the Reformation's priority of grace + Scripture over scholastic synthesis is in part a downstream effect of late-medieval Ockhamism.

"The will is free with regard to indifferent things." (Quodlibetal Questions)

A structural rather than historical lineage: Ockham's logical and ontological parsimony are the medieval ancestor of modern analytic philosophy's preference for sparse ontologies.

"It is in vain to use more when fewer will do." (Variants of the razor throughout the corpus)