Vicious Circle

This one started life as a term in formal logic, not everyday speech. A "vicious circle" originally described a flawed circular argument, one that tries to prove a statement using a second statement whose own proof depends on the first, a logical dead end logicians had been criticising since the early 1600s. The specific English phrase, borrowed from the French cercle vicieux, is documented from 1792. Doctors adopted it in the 19th century to describe medical conditions where symptoms worsen each other, and writers like Henry James picked it up figuratively soon after, giving it the broader, self-reinforcing sense used today.