“But suppose you prepare the soil by a crop of the ad hominem argument. You say to your friend, after looking admiringly at his possessions, ‘It seems to me that all your geese are swans.’ He answers cordially, ‘That’s just what I was thinking myself.’ Now you have nicely prepared the ground for further operations.
“While controversial theologians have always had a fondness for arguments in a circle, the ad hominem arguments have been largely cultivated by politicians. More than a generation ago Jeremy Bentham published a work called ‘Political Fallacies.’ He described those that are indigenous to the British Isles. Almost all on his list were of the ad hominem variety. He described particularly those which could be grown to advantage in the Houses of Parliament. Since Bentham’s day, much has been done in America in the way of propagating new varieties. Many of these, though widely advertised, have not yet been scientifically described. I have thought that if my present book is well received, I might publish another covering this ground. It will probably be entitled, ‘Reasoning for Profit; or Success with Small Fallacies.’
“The great essential in arguments of this kind is to have a thorough knowledge of the soil. Given the right soil, and the most feeble argument will flourish. Take, for example, the arguments for the divine right of kings to rule, once much esteemed by court preachers. Of course the first necessity was to catch your kings. The arguments in themselves were singularly feeble, but they flourished mightily in the hotbeds of royalty. The trouble was that they did not bear transplanting.
“Half a century ago there were a dozen thrifty arguments for human slavery. They are, abstractly speaking, as good now as they ever were, but they have altogether passed out of cultivation.
“In landscape gardening groups of the ad hominem arguments skillfully arranged are always charming. Much discrimination is needed for the adornment of any particular spot. Suppose you were called upon to furnish fallacies for an Amalgamated Society of Esoteric Astrologers. You might safely, in such fertile soil and tropical climate, plant the most luxuriant exotics. Such airy growths, however, would be obviously inappropriate for a commercial club composed of solid business men. You would for them choose rather a sturdy perennial, for example, the argumentum ad Pennsylvaniam, or tariff-bearing argument.
“It grows thus:—
The tariff is that which conduces to our prosperity.
A tax does not conduce to our prosperity.
Therefore, a tariff is not a tax.
“Persons who have confined their logical exercises to the task of convincing impartial minds have no idea of the exhilaration which comes when one has only to convince a person of the wisdom of a course of action he has already taken. There is really no comparison between the two. There is all the difference that there is between climbing an icy hill and sliding down the same hill on a toboggan. There is no intellectual sport equal to that of tobogganing from a lofty moral premise to a congenial practical conclusion. We go so fast that we hardly know how we got to the bottom, but there we are, safe and sound. We have only to choose our company and hold on; gravitation does the rest. It is astonishing what conclusions we can come to when we do our reasoning in this pleasantly gregarious fashion.
“Ignoratio Elenchi, or the fallacy of irrelevant conclusion. This is not a natural species, but the result of artifice. It is a familiar kind of argument. It begins well, and it ends well, but you have a feeling that something has happened to it in the middle. You have noticed in the orchard an apple tree that starts out to be a Pippin, but when the time comes for it to bear fruit it has apparently changed its mind, and has concluded to be a Rhode Island Greening. Of course you are aware that it has not really changed its mind, for the laws of Nature are quite invariable. The whimsicality of its conduct is to be laid not upon Nature, but upon Art. The gardener has skillfully grafted one stock upon another. The same thing can be done with an argument. You have often observed the way in which a person will start out to prove one proposition and after a little while end up with the triumphant demonstration of something that is quite different. He shows such an ability at ratiocination that you cannot help admiring his reasoning powers, though it is hard to follow him. Your bewilderment comes from the fact that you had expected the original seedling to bring forth after its kind, and had not noticed the point where the scion of a new proposition had been grafted on.
“Many persons are not troubled at all when the conclusions are irrelevant. They rather like them that way. If an argument will not prove one thing, then let it prove another. It is all in the day’s work. To persons with this tolerant taste the variety afforded by the use of the ignoratio elenchi is very pleasing.”