This node seems to be infected with a certain modernistic smugness. Medieval philosophers could have and certainly did discuss "How many angels can dance on the head of a pin?" with the utmost seriousness.
While the pin metaphor is not used, Thomas Aquinas’ Summa Theologiae certainly covers all the metaphysics necessary.
Aquinas was not talking about the images of fat, winged cherubim which come to mind when we hear the word “angel”. By discussing angels, Aquinas reasoned about non-corporeal substances. Today, we might similarly discuss whether it makes sense to talk about a subatomic particle which has energy, position and velocity but no mass. The Summa’s section on angels (Questions 50-64) is the first after the topic of creation. Angels are pure spirit, and the section on angels stands, in the scheme of the Summa, for a discussion of the nature of spirit. That section is followed by one treating matter, and then a section on the combination of spirit and matter, which is a Human Being.
The Summa is presented in a debate format: a question is asked, then positions pro and con and stated. The first question regarding angels is: do purely spiritual things exist, or is spirit found only in conjunction with matter? Today, one might ask, does consciousness exist apart from the brain? The referents are different but the metaphysical/philosophical question is the same.
As for the dancing, the question is, do purely spiritual beings occupy any space? Do they have extension as well as location? For a pin head, the possible answers are no angels (they have neither place nor space), one angel (they have both place and space), and infinitely many angels (they have place but take up no space).
In Aquinas’ view, the correct answer was “infinitely many”: while angels have no bodies and occupy no space, they do have location. The debate therefore illustrates the distinction between extension and location. Fundamental metaphysical questions like this were certainly debated in medieval universities, whether or not the angels and pinheads illustration was used.