The Positive Ad Homimen is, in effect, a reverse Ad Hominem. A standard Ad Homimem is a fallacy in which a claim (or argument) is rejected based on an attack on person presenting the claim or argument. A Positive Ad Hominem occurs when a claim or argument is accepted based on an irrelevant positive quality of the person making it. Typically, this fallacy involves two steps. First, something positive (but irrelevant) about the person making the claim, their circumstances, or their actions is made. Second, this is taken to be evidence for their claim or that their argument is good. This fallacy has the following form:
Premise 1: Person A makes claim or argument X.
Premise 2: Person B notes a positive (but logically irrelevant) feature of A.
Conclusion: Therefore, A’s claim is true, or A’s argument is good.
The reason why an ad Hominem (of any kind) is a fallacy is that the character, circumstances, or actions of a person do not (in most cases) have a bearing on the truth or falsity of the claim being made. Like the negative Ad Hominem, the Positive Ad Hominem relies on psychological force. Just as (alleged) negative qualities can incline people to reject claims made a person, (alleged) positive qualities can incline people to accept claims. People often commit this fallacy in the context of a Fallacious Appeal to Authority when they mistake irrelevant positive qualities as evidence of expertise. For example, people often listen to celebrities because they are famous, rich, or well liked. But none of these qualities are relevant to being a credible expert. A more subtle error is mistaking expertise in one area (a positive quality) as conferring expertise in other areas. For example, a famous expert on physics might be believed when they speak about philosophy, even though they have no expertise in the field.
As with the negative Ad Hominem, a person can lie when making a Positive Ad Hominem. For example, a person might falsely attribute positive qualities to themselves or a politician they like to persuade others to believe them. This fallacy can be inflicted on others in good or bad faith or self-inflicted. In good faith cases, the person committing the fallacy believes that the subject has the good qualities and is ignorant of the fallacy. In bad faith cases, the person using the fallacy knows it is a fallacy or is lying about the good qualities (or both).
There are cases when facts about a person are relevant to assessing that person’s credibility. There are also cases in which non-fallacious arguments can be made based on a person’s relevant positive qualities. For example, it would not be a fallacy to accept an expert’s claim in their field if they are educated in the field, unbiased, and experienced in the field. For a discussion of when positive qualities are relevant to accepting a claim, see the Appeal to Authority.
Defense: As with any Ad Hominem, the defense is to keep in mind that the irrelevant qualities of the person making a claim or argument are irrelevant to the truth of their claim or the quality of their argument. It is especially important to be on guard in cases where you respect, like or agree with the person.
“That Glenn is such a nice man and always so passionate about what he says. So, he must be right that we should buy gold.”
Sally: “What he said was ridiculous. Why do believe him?”
Janet: “Honey, with a butt like that, how can he be wrong?”
Sally: “Well, he was certainly talking out of it.”
“I had some doubts about him, but then I realized that he was wearing an expensive suit. Plus, he had that British accent. There is no way he could be lying about this deal, so I am sure it will be a great investment!”
Henry: “That guy doesn’t seem to know what he is talking about.”
Jay: “Well, he is a very successful businessman; he says he has made millions in real estate. Plus, he tells it like it is.”
Henry: “So you think he is right that the United States should switch to renewable energy?”
Jay: “Yes, I mean he is rich. So, I am sure he is right about solar power.”