A man posing a question such as “How do you know what you know?” in order to prove his own brilliance and depth, while hopefully stumping the woman he is talking to. The man posing the question honestly believes that he is the smartest and most unique individual.
Woman: says something pointed, intelligent, and for whatever reason, threatening to the mansplainer.

Mansplainer uses Stoner’s Gambit: “How do you know words mean anything?”
by kitdoor January 11, 2011
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