Thomas Aquinas's Virtual Distinction and Duns Scotus's Formal Distinction

According to Aquinas and Scotus, some items are identical and nevertheless discernible. That is, a and b can be identical even while a is F and b is not F. They say that items that relate this way are distinct in ratio. That there are items that are related in this way is very controversial, both in the medieval period and especially today, where it is almost universally rejected. Aquinas and Scotus, however, agree that the divine attributes and the essential properties of creatures each relate in this way. This dissertation explicates the nature of the distinction in ratio in the thought of Aquinas and Scotus. Chapter 1 introduces the topic and presents the contrasting opinions of the Nominalists who reject that identical items can be distinct in ratio. Chapter 2 presents the opinion of Aquinas, who thinks that items’ being distinct in ratio (which distinction comes to be called the “virtual distinction”) is grounded in the imperfect concepts of creatures which capture only some of the perfection of the object cognized. The third chapter explicates Scotus’s distinction in ratio, which he calls the formal distinction. According to Scotus, it is simply a fact of ontology that identicals can be discernible in the relevant sense, and consequently he develops a new theory of what identity amounts to such that it does not entail indiscernibility. The fourth chapter uses the insights from the previous two chapters to present Aquinas and Scotus’s respective theories of universals. I argue that their doctrines can only be properly understood through understanding their thought on the distinction in ratio and that the differences between them reduce to their different understandings of how the distinction in ratio functions. Chapter 5 evaluates the respective views discussed, and concludes that the Thomistic and Ockhamistic views should be rejected in favor of the Scotistic view or the Hardliner view (which has Adam Wodeham and Gregory of Rimini as perhaps its most prominent defenders).