Murder

In rare and unusual cases, however, a speaker’s character or position is a reason to doubt the truth of what he says. Suppose that Lucy is suspected of committing murder, but Louie testifies that he was with her at the time of the murder. Then the prosecution shows that Louie provided a similar alibi for an accused murderer at ten trials in the past year, and every time he was found to have lied in exchange for money. Louie never testifies without being paid, he says whatever he is paid to say, and people do not hire him if they have any better defense. This background about Louie provides some reason to believe that what Louie said was false—that he was not with Lucy at the time of the murder. Lucy still might not have committed the murder, but we can’t take Louie’s word for it. Ad hominem arguments like this can be called deniers, since they deny the truth of what is said or the strength or soundness of an argument. Although most ad hominem deniers are fallacious, the case of Louie shows that a few are not.

A different kind of ad hominem argument questions a person’s right to make a claim or present an argument. Imagine that the Senate is debating tax rates. During one session, Tad stands up and argues for a reduction in taxes. Tad can be criticized if he is not a senator, because then he lacks the status that confers the right to speak in this setting. Even outside of any for- mal institution, if a neighbor tells someone that she ought to take her chil- dren to a certain church, the mother might respond, “Mind your own business, you busybody.” Responses like this can be called silencers, because they revoke the right to speak without necessarily denying the truth of what is said.