How to Win Every Argument: The Use and Abuse of Logic (2006)

88 How to Win Every Argument

Hominem (abusive), argumentum ad

If you cannot attack the argument, attack the arguer. While an
insult itself is not fallacious, it is if made in a way calculated to
undermine an opponent's argument, and to encourage an
audience to give it less weight than it merits. When this is done,
the famous argumentum ad hominem abusive is committed.

Dr Green argues very plausibly for fluoridation. What he does not tell us

is that he is the same Dr Green who ten years ago published articles in

favour of both euthanasia and infanticide.

(Unless his argument is that fluoride will kill off the old people and

infants more effectively, it is hard to see how this bears on the

arguments for or against fluoride.)

The fallacy here, as with most fallacies of relevance, is that the
argument is not treated on its merit. Arguments should stand or
fall by their own qualities. Strictly speaking, the merits of the
arguer do not come into it. Even the public relations industry is
not always in error. It is only because we are reluctant to suppose
that a good and sensible argument can come from a bad and
stupid source that the ad hominem abusive has any effect.

Now I come to Professor Robinson's argument in favour of amalga-

mating the two colleges. Far be it from me to reopen old wounds by

referring to the Professor's conviction three years ago for drunk driving,

but we have to ask ourselves...

(Note the ritual denial. It is usually the signal for an ad hominem

abusive, 'I don't wish to be catty, but - miaow.')

There are many forms of this fallacy, some so specialized that

they are identified and named as separate fallacies. Effective use

demands a bold attempt to make the abuse appear to have some