Ad Hominem

Latin for "to the person," argumentum ad hominem entered formal logic in the late 16th century. Aristotle had already catalogued the tactic in his 350 BCE Sophistical Refutations, where attacking the questioner rather than the argument was classified as sophistry. John Locke later distinguished it as a rhetorical move in his 1689 writings. By the early 20th century, the term narrowed to its current meaning: a fallacy in which personal attacks substitute for reasoned disagreement.