The following is a quote from a review handout authored by my Medieval Philosophy professor, William Frank, at the University of Dallas. This is quite possibly the most intriguing thing I’ve ever read about William of Ockham. I’ve bold faced the relevant parts.
…There is a lot of anxiety aroused by the detachment of truth and knowledge from existence. What I mean is this. The default philosophical position is that knowledge represents reality and that mind is fundamentally receptive of reality. The conceit here is that knowledge require a commonality between thing and thought. The commonality is naively understood in terms of representation, something like a “picture.” One and the same intelligible structure is thought to be in both thing and in the mind. The idealist has the thing represent the idea; the realist has the idea represent the thing. Either way, some existent is common to knowing and being.
The terms of knowledge are universals; they involve both generality and predicability. How can they be true, even universally and necessarily true, if what exists primarily are singular individuals and especially if what is singular and individual is material, mutable, and only accessible through sense perception. If “to know” is to “have” what is real, then universals must be real. Philosophy assumes the task of accounting for that reality.
Ockham, who was anticipated by Abelard, thinks of the knowing mind differently. The units of knowledge, concepts, propositions, and the words and grammar in which they are expressed and communicated, are acts or works of the mind that are not images or representations but rather signs. Mind-at-work in language, with its words and grammar and with its concepts and logic, does not “have” or “possess” or “contain” things and their intelligibilities: it signifies them.
The inherited historical problem of nominalism arises subsequently in what later theologians and philosophers do with Ockham’s developments. Nominalism gets its “stink” or its “revolutionary luster,” depending on one’s conservative or liberal point of view,” when the natural basis of Ockham’s simple signification and supposition theory is dismissed. Ockham’s semantic theory is an account of human intellect as actual engagement with the world, wherein the sign (concept or word) cannot be detached from the signified (individuals and groups in their similarities and dissimilarities) withotu ceasing to be what it is, namely, a meaning or sign. But what happens is that the mind, outfitted with its sign-system, becomes its own kind of thing. Indeed, it becomes “the self” or “consciousness.” The philosophers and theologians begin to imagine that they think thoughts or concepts. In other words, mental entities become thought’s objects. These thought-objects are experienced as signs, but since they “exist in” the mind or are experienced “within consciousness,” one of the great problems that preoccupies modern philosophy is how to get outside the mind. How to account for any representative truthfulness of the mind’s picture of the world?…
Remember that Ockham is often described as totally destroying metaphysics and opening the door to unrestricted nominalistic skepticism in the sense that only individual things as individual things are knowable. If Dr. Frank is right in his take on Ockham, the man was actually pretty conservative himself but it was later thinkers who twisted him in the direction of nominalistic skepticism. At any rate, if I may use a philosophical pun here, the “clear and distinct ideas” about the downgrade from Ockham to the Cartesian difficulty of knowers being trapped inside their own heads, each taking his own take on things to be infallible Truth, is to me provocative and deserves some serious follow-up