Practical Argumentation Part 20

B. Argument from effect to effect.

1. Do the combined tests of argument from effect to cause and from cause to effect hold?

V. Example.

A. Is there any fundamental difference between the case in hand and the case cited as an example?

FALLACIES.

A fallacy is an error in reasoning. The preceding part of this chapter has already suggested tests that will expose many such faults, but there are a few errors which, because of their frequency or their inadaptability to other cla.s.sification, demand separate treatment.

This book follows the plan of most other texts on argumentation, and treats these errors under a separate head marked fallacies. To detect a fallacy in another's argument is to weaken, if not to destroy, his case; to avoid making a fallacy in one's own argument means escape from humiliation and defeat. Hence, a knowledge of fallacies is one of the most essential parts of a debater's equipment.

The cla.s.sification given here does not pretend to be exhaustive; it does, however, consider the most common and insidious breaches of reasoning that are likely to occur, and the following pages should be studied with great care.

I. BEGGING THE QUESTION. (PEt.i.tIO PRINCIPII.)

1. MERE a.s.sUMPTION. Begging the question means a.s.suming the truth of that which needs proof. This fallacy is found in its simplest form in epithets and appellations. The lawyer who speaks of "the criminal on trial for his life," begs the question in that he a.s.sumes the prisoner to be a criminal before the court has rendered a verdict. Those writers who have recently discussed "the brutal game of football"

without having first adduced a particle of proof to show that the game is brutal, fall into the same error. An unpardonable instance of question-begging lies in the following introduction, once given by a debater who was attacking the proposition, "_Resolved_, That the federal government should own and operate the railroads in the United States":--

"We of the negative will show that the efficient and highly beneficial system of private owners.h.i.+p should be maintained, and that the impracticable system of government owners.h.i.+p can never succeed in the United States or in any similarly governed country."

Private owners.h.i.+p and government owners.h.i.+p may possess these qualities attributed to them, but the debater has no right to make such an a.s.sumption; he must _prove_ that they have these qualities.

2. a.s.sUMPTION USED AS PROOF. Such barefaced a.s.sumptions as the preceding usually do little damage except to the one who makes them.

They are not likely to lead astray an audience of average intelligence; on the other hand, they do stamp the arguer as prejudiced and illogical. But when a.s.sumptions are used as proof, hidden in the midst of quant.i.ties of other material, they may produce an unwarranted effect upon one who is not a clear thinker, or who is off his guard. If, without showing that football is brutal, one calls it an extremely brutal game, and then urges its abolishment on the ground of its brutality, he has used an a.s.sumption as proof, and has, therefore, begged the question. The debater who stated, without proving, that vast numbers of unskilled laborers were needed in the United States, and then urged this as a reason why no educational test should be applied to immigrants coming to this country, furnished an example of the same fallacy.

3. UNWARRANTED a.s.sUMPTION OF THE TRUTH OF A SUPPRESSED PREMISE. The student is already familiar with the enthymeme. The enthymeme const.i.tutes a valid form of reasoning only when the suppressed premise is recognized as true. Therefore, whenever an arguer makes use of the enthymeme without attempting to establish a suppressed premise whose truth is not admitted, he has argued fallaciously. This is a third method of begging the question. To ill.u.s.trate: In advocating the abolishment of football from the list of college athletic sports, one might reason, "Football should be abolished because it obviously exposes a player to possible injury." The suppressed premise in this case would be: All sports which expose a player to possible injury should be abolished. Failure to prove the truth of this unadmitted statement const.i.tutes the fallacy.

4. a.s.sUMPTION EQUIVALENT TO THE PROPOSITION TO BE PROVED. It is not surprising that a man carried away with excitement or prejudice should make a.s.sumptions that he does not even try to substantiate, but that anyone should a.s.sume the truth of the very conclusion that he has set out to establish seems incredible. Such a form of begging the question, however, does frequently occur. Sometimes the fallacy is so hidden in a ma.s.s of ill.u.s.tration and rhetorical embellishment that at first it is not apparent; but stripped of its verbal finery, it stands out very plainly. The following pa.s.sage written on the affirmative side of the proposition, "_Resolved_, That the college course should be shortened to three years," will serve as a particularly flagrant ill.u.s.tration:--

It is a well-known fact that in the world of to-day time is an essential factor in the race for success. No young man can afford to dawdle for four long years in acquiring a so-called "higher"

education. Three-fourths of that time is, if anything, more than sufficient in which to attain all the graces and culture that the progressive man needs.

It is evident that the "argument" in this case consists of nothing more than a repet.i.tion of the proposition.

5. ARGUING IN A CIRCLE. Another phase of begging the question consists of using an a.s.sumption as proof of a proposition and of then quoting the proposition as proof of the a.s.sumption. Two a.s.sertions are made, neither of which is substantiated by any real proof, but each of which is used to prove the other. This fallacy probably occurs most frequently in conversation. Consider the following :--

A. "The proposed system of taxation is an excellent one."

B. "What makes you think so?"

A. "Because it will be adopted by the legislature."

B. "How do you know it will?"

A. "Because it is a good system and our legislators are men of sense."

This fallacy occurs when one proves the authority of the church from the testimony of the scriptures, and then establishes the authenticity of the scriptures by the testimony of the church. A similar fallacy has been pointed out in the works of Plato. In _Phaedo_, he demonstrates the immortality of the soul from its simplicity, and in the _Republic_, he demonstrates the simplicity of the soul from its immortality. The following fragment of a brief argues in a circle:--

I. This principle is in accordance with the principles of the Democratic party, since

A. The leader of the Democratic party believes in it, for

1. As the leader of the party, he naturally believes in Democratic principles.

II. AMBIGOUS TERMS. (EQUIVOCATION; CONFUSION OF TERMS.)

The fallacy of ambiguous terms consists of using the same term in two distinct senses in the same argument. Thus if one were to argue that "no designing person ought to be trusted; engravers are by profession designers; therefore they ought not to be trusted," it is quite apparent that the term "design" means totally different things in the two premises. The same fallacy occurs in the argument, "Since the American people believe in a republican form of government, they should vote the Republican ticket." Again:--

"Interference with another man's business is illegal;

"Underselling interferes with another man's business;

"Therefore underselling is illegal."

J. S. Mill in his _System of Logic_ discusses the fallacy of ambiguous terms with great care. In part he says:--

The mercantile public are frequently led into this fallacy by the phrase "scarcity of money." In the language of commerce, "money" has two meanings: _currency,_ or the circulating medium; and _capital seeking investment,_ especially investment on loan. In this last sense, the word is used when the "money market" is spoken of, and when the "value of money" is said to be high or low, the rate of interest being meant. The consequence of this ambiguity is, that as soon as scarcity of money in the latter of these senses begins to be felt,--as soon as there is difficulty of obtaining loans, and the rate of interest is high,--it is concluded that this must arise from causes acting upon the quant.i.ty of money in the other and more popular sense; that the circulating medium must have diminished in quant.i.ty, or ought to be increased. I am aware that, independently of the double meaning of the term, there are in the facts themselves some peculiarities, giving an apparent support to this error; but the ambiguity of the language stands on the very threshold of the subject, and intercepts all attempts to throw light upon it.

As countless words and expressions have several meanings, there is almost no limit to the confusion which this fallacy can cause. Some of the most common terms that are used ambiguously are _right_, _liberty_, _law_, _representative_, _theory_, _church_, _state_, _student_.

By carefully defining all terms that have more than one meaning and by insisting on a rigid adherence to the one meaning wherever the term is used, a debater can easily avoid fallacies of this sort in his own argument and expose those of his opponent.

III. FALSE CAUSE.

The fallacy of false cause occurs whenever that which could in no way bring about the effect that is being established is urged as its cause. This fallacy in its most obvious form is found only in the arguments of careless and illogical thinkers. Some college students occasionally draw briefs that contain such reasoning as the following:--

I. The Panama ca.n.a.l should be of the sea-level rather than of the lock type, because

A. The Panama ca.n.a.l will do away with the long voyage around the Horn.

I. Southerners are justified in keeping the franchise away from the negro, for

A. Negroes should never have been brought to America.

B. The Fifteenth Amendment to the Const.i.tution ought not to have been pa.s.sed.

The error of such plainly absurd reasoning as occurs in the preceding ill.u.s.trations needs no explanation. There is one form of the fallacy of false cause, however, that is much more common and insidious and therefore deserves special treatment.

POST HOC ERGO PROPTER HOC. (After this, therefore, on account of this.) This phase of the fallacy consists of the a.s.sumption that since cause precedes effect what has preceded an event has caused it. The most frequent occurrence of the error is to be found in superst.i.tions.

If some one meets with an accident while taking a journey that began on Friday, many people will argue that the accident is the effect of the unlucky day. Some farmers believe their crops will not prosper unless the planting is done when the moon is in a certain quarter; sailors often refuse to embark in a renamed vessel. Because in the past, one event has been known to follow another, it is argued that the first event was the cause of the second, and that the second event will invariably follow the first.

But this fallacy does not find its only expression in superst.i.tions.

To _post hoc_ reasoning is due much of the popularity of patent medicines. Political beliefs, even, are often generated in the same way; prosperity follows the pa.s.sing of a certain law, and people jump to the conclusion that this one law has caused the "good times." Some demagogues go so far as to say that education among the Indians is responsible for the increased death rate of many of the tribes.

A slightly different phase of the _post hoc_ fallacy consists in attributing the existence of a certain condition to a single preceding event, when at the most this event could have been only a partial cause of what followed, and may not have been a cause at all. A medicine that could not have effected a cure may have been of some slight benefit. A law that could not possibly have been the sole cause of "good times" may have had a beneficial effect. To avoid this fallacy, one must be sure not only that the a.s.signed cause is operative, but that it is also adequate.