By Hendrik van der Breggen
The Ad Hominem Fallacy
A fallacy is a mistake in reasoning or argument. Some fallacies are so common that they have been given their own names. The ad hominem fallacy is the mistake of criticizing an arguer instead of his/her argument, when doing so is not relevant. (Argumentum ad hominem is Latin for “argument to/against the man.”)
The ad hominem fallacy occurs when something about the arguer’s person—his/her character, attitude, ethnicity, race, religion, sex, circumstance, or even behaviour—is attacked instead of the truth claims or logical structure of the argument presented, when this something about the arguer’s person has no bearing on the truth or logic of the argument presented.
Some instances of the ad hominem fallacy are easy to spot. Consider the following arguments:
“Einstein is Jewish, therefore his theory of relativity should be rejected.”
“Your doctor is a woman, therefore don’t believe what she says about prostate cancer.”
Clearly, in the above arguments the premise (i.e., the bit before “therefore”) is not relevant to the conclusion (the bit after “therefore”).
But some instances of the ad hominem fallacy are not so easy to spot.
Consider an example from the abortion debate. A pro-life spokesperson—a man—has just set out several detailed arguments for thinking that what is aborted is in fact a human being with the right to life. After his presentation, someone from the audience says the following (loudly and angrily): “You are a man, therefore your arguments against abortion don’t count!”
The above “critique” commits the ad hominem fallacy.
The arguer (the pro-life spokesperson) is being criticized (for being male) resulting in the dismissal of the arguer’s argument (his case concerning the fetus’s status as a human being having rights). Neglected by the critic, however, is the fact that an argument should be assessed on the basis of its merits (or lack thereof), not on the basis of whether the argument has been set out by a male or a female.
The crucial but missed issue is whether the argument is logically cogent; the sex/gender of the arguer is wholly beside the point.
Now consider an example from the homosexuality debate. A gentleman respectfully sets out an argument for questioning the wisdom of celebrating Gay Pride parades, which promote homosexual sex. His argument appeals (1) to a couple of serious medical problems associated with some homosexual sexual practices, especially for males, and (2) to the apparent general difficulty of homosexual couples maintaining long-term monogamous relationships. The response from several critics (stated loudly and angrily): the man is a “homophobe,” therefore we should ignore him.
The above “critique” also commits the ad hominem fallacy.
First, it is important to note that a person can have legitimate, reasonable concerns about a behaviour if there are in fact some serious medical and/or social health issues associated with the behaviour. In other words, not all such concerns are irrational fears or phobias. (As politically incorrect as this may sound, the public does have a legitimate interest in behaviour that may harm people, cost public health dollars, and/or promote domestic arrangements which aren’t in the best interests of children.)
Second, neglected by the critics is the fact (again) that an argument should be assessed on the basis of its merits (or lack thereof), not on the basis of whether the argument has been set out by a homophobe or a non-homophobe.
The crucial but missed issue is whether the argument is logically cogent; the homophobic/non-homophobic attitude of the arguer is wholly beside the point.
A homophobic attitude of the arguer might provide grounds to suspect that the arguer’s argument is poorly constructed; nevertheless, the argument itself should be assessed to determine whether it is in fact poorly constructed.
Of course, sometimes ad hominem arguments are not fallacious, as, say, when a smart lawyer presents good evidence for thinking that a witness is not trustworthy and so the witness’s testimony should not be accepted.
How, then, can we tell the difference between acceptable and non-acceptable ad hominem arguments? Answer: Via the art of critical thinking—coupled with the courage not to be intimidated by irrelevant personal attacks.
(Hendrik van der Breggen, PhD, is assistant professor of philosophy at Providence College, Otterburne, Manitoba. The views in this column do not always reflect the views of Providence.)