How many angels can dance on the head of a pin?

The question “How many angels can dance on the head of a pin?” is typically used as a mocking retort to questions that are thought to be of little usefulness. It’s especially used in reference to philosopher theologians of the Middle Ages like the Scholastics or to theology in general. It’s not a question any of the Scholastics ever actually asked. But medieval philosophy did have plenty of talk about angels, and for good reason. They used angels as subjects for thought experiments to explore concepts like cognition and identity in the most generalized way possible, in the way modern philosophers talk about brains in a vat, brains separated from the body and sent to another planet, philosophical zombies, or people living in a black-and-whiteworld. Their topics are just as relevant today as we develop technologies like artificial intelligence and deepen our understanding of the brain and the mind.