n wrong, it is pernicious. Many of the questions concerning
relations of modern society--as capital and labor--are based upon this
fallacy. Henry Clay was guilty of it when he announced, "Two hundred
years of legislation have sanctioned and sanctified negro slaves as
property." The successful way to dispose of such a fallacy is
illustrated by William Ellery Channing's treatment of this statement.

But this property, we are told, is not to be questioned on
account of its long duration. "Two hundred years of
legislation have sanctioned and sanctified negro slaves as
property." Nothing but respect for the speaker could repress
criticism on this unhappy phraseology. We will trust it
escaped him without thought. But to confine ourselves to the
argument from duration; how obvious the reply! Is injustice
changed into justice by the practice of the ages? Is my
victim made a righteous prey because I have bowed him to the
earth till he cannot rise? For more than two hundred years
heretics were burned, and not by mobs, not by lynch law, but
by the decrees of the councils, at the instigation of
theologians, and with the sanction of the laws and religions
of nations; and was this a reason for keeping up the fires,
that they had burned two hundred years? In the Eastern world
successive despots, not for two hundred years, but for twice
two thousand have claimed the right of life and death over
millions, and, with no law but their own will, have
beheaded, bowstrung, starved, tortured unhappy men without
number who have incurred their wrath; and does the lapse of
so many centuries sanctify murder and ferocious power?

Attacking a Speaker's Character or Principles. Sometimes a speaker who
finds himself unable to attack the truth of a proposition, or the
arguments cited to support it, changes his tactics from the
subject-matter to the opponent himself and delivers an attack upon his
character, principles, or former beliefs and statements. This is
called the _argumentum ad hominem_. In no sense is it really argument;
it is irrelevant attack, and should be answered in a clear accurate
demonstration of its unsuitability to the topic under consideration.
It is unworthy, of course, but it is a tempting device for the speaker
who can combine with it an appeal to the prejudices or passions of his
audience.

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