How does an ad hominem fallacy avoid addressing a person's actual claim?

An ad hominem argument avoids addressing a person's actual claim by shifting the focus from the substance of the argument to the individual making it. Instead of engaging with the facts, logic, or merits of a position, the attacker attempts to discredit the speaker by impugning their character, motives, or personal traits.1

This approach is considered a fallacy when the personal attack is irrelevant to the truthfulness of the claim. By focusing on subjective or idiosyncratic characteristics—such as a person's appearance, background, or perceived biases—the attacker seeks to persuade an audience to dismiss the argument without ever having to address its underlying reasoning.1

Ethically, this tactic is problematic because it prioritizes manipulation over truth. It relies on pathos (appealing to emotions) and ethos (attacking the speaker's character) to bypass the logos (the logical substance) of a debate. While questioning character can be legitimate in specific contexts, such as evaluating the credibility of a witness, using personal attacks to sidestep substantive issues undermines honest discourse and the pursuit of truth.1