An ad hominem, short for argumentum ad hominem, is a general category of fallacies in which
a claim or argument is rejected on the basis of some irrelevant fact about the author of
or the person presenting the claim or argument. Fallacious Ad hominem reasoning is normally
categorized as an informal fallacy, more precisely as a genetic fallacy, a subcategory of fallacies
of irrelevance. Ad hominem reasoning is not always fallacious, for example, when it relates
to the credibility of statements of fact. Ad hominem arguments are the converse of appeals
to authority, and may be used in response to such appeals.
Ad hominem as it is discussed in this article refers to the logical fallacy argumentum ad
hominem, and not to the literal Latin phrase ad hominem.
Types
Abusive Abusive ad hominem usually involves attacking
the traits of an opponent as a means to invalidate their arguments. Equating someone's character
with the soundness of their argument is a logical fallacy. Mere verbal abuse in the
absence of an argument, however, is not ad hominem nor any kind of logical fallacy.
Ad hominem abuse is not to be confused with slander or libel, which employ falsehoods
and are not necessarily leveled to undermine otherwise sound stands with character attacks.
Circumstantial Ad hominem circumstantial points out that
someone is in circumstances such that they are disposed to take a particular position.
Ad hominem circumstantial constitutes an attack on the bias of a source. This is fallacious
because a disposition to make a certain argument does not make the argument false; this overlaps
with the genetic fallacy. The circumstantial fallacy applies only where
the source taking a position is only making a logical argument from premises that are
generally accepted. Where the source seeks to convince an audience of the truth of a
premise by a claim of authority or by personal observation, observation of their circumstances
may reduce the evidentiary weight of the claims, sometimes to zero.
Examples: Mandy Rice-Davies's famous testimony during
the Profumo Affair, "He would [say that], wouldn't he?", is an example of a valid circumstantial
argument. Her point was that a man in a prominent position, accused of an affair with a callgirl,
would deny the claim whether it was true or false. His denial, in itself, provides little
evidence against the claim of an affair. Note, however, that this argument is valid only
insofar as it devalues the denial; it does not bolster the original claim. To construe
invalid evidence of the denial as valid evidence of the original claim is fallacious; however
likely the man in question would be to deny an affair that did in fact happen, he is no
less likely to deny an affair that never happened. Tu quoque
Ad hominem tu quoque refers to a claim that the source making the argument has spoken
or acted in a way inconsistent with the argument. In particular, if Source A criticizes the
actions of Source B, a tu quoque response is that Source A has acted in the same way.
This argument is fallacious because it does not disprove the argument; if the premise
is true then Source A may be a hypocrite, but this does not make the statement less
credible from a logical perspective. Indeed, Source A may be in a position to provide personal
testimony to support the argument. For example, a father may tell his son not
to start smoking as he will regret it when he is older, and the son may point out that
his father is or was a smoker. This does not alter the fact that his son may regret smoking
when he is older. Guilt by association
Guilt by association can sometimes also be a type of ad hominem fallacy if the argument
attacks a source because of the similarity between the views of someone making an argument
and other proponents of the argument. This form of the argument is as follows:
Source S makes claim C. Group G, which is currently viewed negatively
by the recipient, also makes claim C. Therefore, source S is viewed by the recipient
of the claim as associated to the group G and inherits how negatively viewed it is.
An example of this fallacy could be "My opponent for office just received an endorsement from
the Puppy Haters Association. Is that the sort of person you would want to vote for?"
Other types of ad hominem reasoning When an ad hominem argument is made against
a statement, it is important to draw a distinction whether the statement in question was an argument
or a statement of fact. In the latter case the issues of the credibility of the person
making the statement may be crucial. Doug Walton, Canadian academic and author,
has argued that ad hominem reasoning is not always fallacious, and that in some instances,
questions of personal conduct, character, motives, etc., are legitimate and relevant
to the issue, as when it directly involves hypocrisy, or actions contradicting the subject's
words. The philosopher Charles Taylor has argued
that ad hominem reasoning is essential to understanding certain moral issues, and contrasts
this sort of reasoning with the apodictic reasoning of philosophical naturalism.
See also
References
Further reading Hurley, Patrick. A Concise Introduction to
Logic. Wadsworth. pp. 125–128, 182. ISBN 0-534-52006-5. Copi, Irving M.; Cohen, Carl. Introduction
to Logic. pp. 97–100. Walton, Douglas. Ad Hominem Arguments. Tuscaloosa:
University Alabama Press. External links
Ad hominem at PhilPapers Nizkor.org: Fallacy: Ad Hominem.
Nizkor.org: Fallacy: Circumstantial Ad Hominem. Argumentum Ad Hominem
University of Winnipeg: Argumentation Schemes and Historical Origins of the Circumstantial
Ad Hominen Argument PDF (70.2 KB) Logical Fallacies: Ad Hominem