As students
of logic know, not every appeal to authority is a fallacious appeal to authority.
A fallacy is committed only when the purported authority appealed to
either does not in fact possess expertise on the subject at hand, or can
reasonably be supposed to be less than objective. Hence if you believed that PCs are better
than Macs entirely on the say-so of either your technophobic orthodontist or
the local PC dealer who has some overstock to get rid of, you would be committing
a fallacy of appeal to authority -- in the first case because your
orthodontist, smart guy though he is, presumably hasn’t much knowledge of
computers, in the second case because while the salesman might have such
knowledge, there is reasonable doubt about whether he is giving you an unbiased
opinion. But if you believed that PCs
are better than Macs because your computer science professor told you so, there
would be no fallacy, because he presumably both has expertise on the matter and
lacks any special reason to push PCs on you.
(That doesn’t necessarily mean he’d be correct, of course; an argument can be mistaken even if it is
non-fallacious.)
Similarly,
not every ad hominem attack -- an
attack “against the man” or person -- involves a fallacious ad hominem.
“Attacking the man” can be entirely legitimate and sometimes even called
for, even in an argumentative context, when
it is precisely the man himself who is the problem.
