In an argument, ad personam, short for argumentum ad personam, is a tactic aimed at discrediting one's opponent by attacking his personality, unrelated to the substance of the debate.
In his treatise The Art of Being Always Right, the German philosopher Arthur Schopenhauer lists this technique under the title of Stratagem No. 38 (both last listed and last resort):[1]
Ad personam and ad hominem are distinct. The former is a personal attack, unrelated to the subject matter of the debate, which aims to discredit the person of the opponent regardless of his arguments; the latter focuses on the argumentation, reasoning or behavior of the opponent in relation to the subject matter of the debate, rather than directly on the subject matter of the debate itself.[2] [3]
In his Manuel de Polémique, Stéphane Muras outlines the distinction between an argument concerning character (ad hominem) and an argument concerning personal attributes (ad personam).[4] An ad hominem argument pertains to what the opponent has revealed about themselves, identifying an inconsistency between the thesis they are currently defending and a previous thesis, either through their words or through concrete and proven actions. This approach addresses the public figure's credibility. In contrast, an ad personam argument invokes the opponent's inherent identity, which does not involve a conscious decision. This includes factors such as their familial rank, position in a hierarchy, age, physical characteristics, geographical origin, or even zodiac sign.