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.

The author has seen the entire population of Rome agitated because in a Senatorial debate one speaker attacked the family reputation of one of his opponents—­a matter which, even if true, certainly had nothing to do with the bill under discussion.  Political campaigns used to be disgraced by a prevalence of such appeals for votes.  We may pride ourselves upon an advance in such matters, but there is still too much of it to let us congratulate ourselves upon our political good manners.  You cannot ascribe bad faith to a man who argues now from a different attitude from the one he formerly supported.  Changes of conviction are frequent in all matters.  A man must be judged by the reasons he gives for his position at any one time.  Many a person, who ten years ago would have argued against it, now believes a League of Nations possible and necessary.  Many a person who a few years back could see no advantage in labor organizations is anxious now to join an affiliated union.

If you find the suggestion of such an attack in any of your own speeches, cast it out.  If it is ever used against you, refute it by the strength of arguments you deliver in support of your position.  Remove all assertions which do not relate to the debated topic.  Make your audience sympathize with your repudiation of the remarks of your opponent, even though he has succeeded in delivering them.