John Duns Scotus, commonly called Duns Scotus, was a Scottish Catholic priest and Franciscan friar, university professor, philosopher, and theologian. He is one of the four most important Christian philosopher-theologians of Western Europe in the High Middle Ages, together with Thomas Aquinas, Bonaventure, and William of Ockham.
Scotus' view of universals is known as Scotistic realism. Scotus is generally considered to be a realist (as opposed to a nominalist) in that he treated universals as real, but he held that they exist both in particular things and as concepts in the mind (as opposed to a Platonic "third realm").
He followed Aristotle in asserting that the subject matter of metaphysics is "being qua being" (ens inquantum ens). Being in general (ens in communi), as a univocal notion, was for him the first object of the intellect.
