We are all taught that attacking your opponent's character instead of their argument is the ultimate debate foul. But the term ad hominem has a far more tactical history than the modern insult it has become. This deep dive traces the concept from Aristotle's analysis of sophist word tricks like the two-eyed man riddle, through Sextus Empiricus and the argument from commitment (ex concessis) revived by Galileo and Locke, to Richard Whately's sweeping 19th-century definition that turned it into a textbook genetic fallacy. Along the way, James Madison's Federalist No. 40 provides the rational ideal: judge the advice, not the person who gives it.

The episode then breaks down the four modern flavors of ad hominem with concrete examples: the tu quoque hypocrisy attack (the overweight doctor prescribing a diet), the circumstantial bias attack (the ...