Ad Hominem: Occurs when someone attacks the character or motives of a person instead of focusing on the issues. Colburn: In this clip, Homer attacks the credibility of Ray Patterson simply because he appears old. In other words, he asserts that Patterson is not competent because he has gray hair.
Patterson's ideas are of course independent of his looks. By not seeing Patterson for his ideas and instead seeing him in terms of his looks, Homer commits the Ad Hominem Fallacy. Subscribe to Colburn Classroom and be on the lookout for new videos.