HEADS OF PINS
Australian Mathematical Society Gazette, volume 20, Number 4, p. 127
Bob Berghout and Garry Tee (volume 20, nos. 1 and 3) ask about the origin of the ridiculous libel that the medieval scholastics examined "such matters as how many angels could fit on the head of a pin". The earliest mention I know of is in Chillingworth's Religion of Protestants a Safe Way to Salvation (1638, reprinted 1972, 12th unnumbered page of the preface), where he accuses scholastics (unnamed, of course) of debating " Whether a Million of Angels may not fit upon a needles point?" As to the truth of the allegation itself, H.S. Lang, author of Aristotle's Physics and its Medieval Varieties (1992), and in a position to know if anyone does, writes (p. 284): "The question of how many angels can dance on the point of a needle, or the head of a pin, is often attributed to 'late medieval writers' ... In point of fact, the question has never been found in this form".
The middle ages attracts this sort of story: "In the middle ages it was believed the earth was flat", "Galileo showed medieval physics was wrong by dropping weights from the Leaning Tower of Pisa", and so on. They are the equivalents in the history of ideas to urban myths like the cat in the microwave.
Addendum: Perhaps the final answer to this medieval conundrum lies in a casual remark made to Senate by the Vice-Chancellor of Newcastle University, Professor Raoul Mortley "The answer is of course well known; fewer if fat, more if thin". (The Editor)
On this question, a discussion; another.
Aquinas does discuss "whether several angels can be in the same place at the same time" (Summa theologiae bk. I q. 52 art. 3, but that does not have the farcical ring of the original.
More generally, `Myths about the Middle Ages' and `The genius of the scholastics, and the orbit of Aristotle'.