In the especial case to which this refers there may or there may not have been bribery; but it is well to bear in mind that this editorial proves nothing. It amounts merely to saying that the vote happened after the interview and was therefore the result of it; so that it is in reality one of those fallacies which in a simpler form appear so absurd. Yet readers in abundance accept this sort of thing as proof, especially when political prejudice inclines them to believe it. It would seem that a little common sense and a little care in examination were all that could be needed to dispose of specious errors of this class, yet they every day prevail.
The third fallacy is that of analogy. Analogy proves a probability, but it cannot establish a certainty. If a young woman has refused a dozen suitors, it is manifestly absurd to say that this proves that she will be equally unkind to the thirteenth. Politicians reason by analogy that a State which hitherto has gone Republican or Democratic may be counted upon to give a majority for its old party; when, lo, a change comes suddenly, and the conclusion is found to be false. That we have always liked the novels of a certain author does not insure that we shall be pleased with his next; that the sun has always risen does not prove that it will rise to-morrow morning; that men have from time immemorial been born with one head does not prove that a child may not be born with two,—as testify the freaks of dime museums. It is true that analogy often establishes a probability so strong that it amounts to a moral certainty. We are justified in acting upon the assumption that the sun will rise to-morrow, and in assuming that any given child of whose birth we hear has but one head. It is important in arguing, however, to bear in mind the difference, whether in one’s own reasoning or in that of an opponent, between analogy and absolute proof. Things which are like the same thing are like each other; but things that are like the same thing are not necessarily equal to each other.
The practical rules which may be given for the writing of Argument are chiefly recapitulations of what has been said.
a. Begin with clear understanding and clear statement of proposition and of terms.
b. Plan argument with reference to the especial point to be established and to the audience to be addressed.
c. Proceed generally from the more obvious to the less clear, and from the weaker to the stronger proof.
d. Be acutely alive to fallacies in any reasoning which is to be refuted, but to fallacies in your own work no less.
e. Never force a proposition or a proof beyond its value.
f. Concede all side issues and irrelevant matters if by so doing you do not lessen the chain of reasoning in points really important, and especially if in so doing you can foster a disposition favorable to your position.
g. Always remember that assertion is not argument.