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

"How many angels can dance on the head of a pin?" (alternatively "How many angels can stand on the point of a pin?") is a phrase that when used in modern contexts can be used as a metaphor for wasting time debating topics of no practical value or on questions whose answers hold no intellectual consequence when more urgent concerns accumulate.

The phrase was originally used in a theological context by 17th-century Protestants to mock medieval scholastics such as Duns Scotus and Thomas Aquinas. Whether medieval scholastics really discussed the topic is, however, a matter of debate. The suggestion is possibly an early modern invention that was intended to discredit scholastic philosophy.

The phrase has also been associated with the fall of Constantinople, with the assertion that scholars debated the topic while the Ottoman Empire besieged the city. In Italian, French, Spanish and Portuguese, the conundrum of useless scholarly debates is linked to a similar question of whether or not angels are sexless. In Polish, the question is about devils instead of angels.