Abstract

Under the traditional classification of medieval positions on the issue of universals, both Aquinas and Buridan would have to be deemed to be “conceptualists”: they both deny the existence of mind-independent, Platonic universals (against “realists”), and they both attribute universality primarily to the representative function of our universal concepts, and thus only secondarily to universal names of human languages (against “nominalists”). Yet, Aquinas is quite appropriately classified as a “moderate realist,” and Buridan as an “Ockhamist nominalist.” This paper will argue that what justifies these more refined classifications is the two authors’ radically different conceptions of the representative function of our universal concepts. The paper will show how this difference results in their opposing judgments concerning the demonstrability of the thesis of the immateriality of the human intellect and will reply to Buridan’s main objection to Aquinas’s argument for this thesis, by pointing out the objection’s conflation of merely indifferent, non-distinctive singular representation with genuinely universal intellectual representation. In its conclusion, the paper will briefly gesture at an important contemporary implication of Aquinas’s thesis concerning a metaphysical limitation of artificial intelligence.