Bl. John Duns Scotus

Blessed John (Johannes) Duns Scotus, O.F.M. (c. 1265 – November 8, 1308) was one of the more important theologians and philosophers of the High Middle Ages. He was nicknamed Doctor Subtilis for his penetrating and subtle manner of thought.

Scotus has had considerable influence on Roman Catholic thought. The doctrines for which he is best known are the "univocity of being," that existence is the most abstract concept we have, applicable to everything that exists; the formal distinction, a way of distinguishing between different aspects of the same thing; and the idea of haecceity, the property supposed to be in each individual thing that makes it an individual. Scotus also developed a complex argument for the existence of God, and argued for the Immaculate conception of Mary.