Practical Argumentation Part 9

Either one by itself may be untrustworthy. The unreliability of evidence given by eyewitnesses is shown by the conflicting stories they frequently tell concerning the same incident even when they are honestly attempting to relate the facts as they occurred. Also, it is always possible that the inferences drawn from a combination of circ.u.mstances may be entirely wrong. When, however, both kinds of evidence are available, each confirming the other and leading up to the same conclusion, then the possibility of error is reduced to a minimum.

The opportunity of the college student for obtaining evidence in his argumentative work is limited. A lawyer before entering upon an important case often spends weeks and months in investigation; scientists sometimes devote a whole lifetime in trying to establish a single hypothesis. But the college student in preparing an argument must obtain his evidence in a few days. There are several sources at his disposal. The first available source is his fund of general knowledge and experience. If a man can establish a statement by saying that he personally knows it to be true, he has valuable proof. Then the people with whom the student comes in contact const.i.tute another source of evidence. Anyone who can give information on a subject that is being investigated is a valuable witness. Especially in discussions on questions which pertain to college life, the opinions and experiences of college men and of prominent educators are unsurpa.s.sed as evidence. But the greatest source of evidence for the student of argumentation is the library. Here he may consult the best thought of all time in every branch of activity. He may review the opinions of statesmen, economists, educators, and scientists, and introduce as evidence their experiences and the results of their investigations.

Here he may familiarize himself with the current events of the world, and draw his own conclusions as to their significance. In fact, a well equipped library treats of all subjects, however broad or narrow they may be, and furnishes evidence for all sorts of debatable questions.

As not all evidence is equally valuable, a large part of the work of argumentation consists in applying tests to the evidence at hand for the sake of determining what facts are irrefutable, what are doubtful, and what are worthless. Moreover, one engaged in argumentation must test not only his own evidence but also that of the other side. No better method of refuting an opponent's argument exists than to show that the facts on which it rests are untrustworthy. Tests of evidence may be divided into two cla.s.ses: tests of the source from which it comes, and tests of the quality of the evidence itself.

A. TESTS OF THE SOURCE OF EVIDENCE.

Since in courts of law, in college debate, and in all kinds of argumentation, facts are established by the testimony of witnesses, the sources of evidence are the witnesses who give it. The debater and the argumentative writer have not the opportunity, as has the lawyer, of producing the witnesses and permitting them to tell their own stories to the audience. He must himself relate the evidence; and, in order that it may be believed, he must tell whence it comes. The sources of evidence may be common rumor, newspapers, magazines, official doc.u.ments, private citizens, or public officials. The extent to which these witnesses are accepted as trustworthy by the people before whom they are quoted determines in a large measure whether or not the evidence will be believed. Tests for determining the trustworthiness of witnesses will next be given.

The first test of the source of evidence should be:--

(1) _Is the witness competent to give a trustworthy account of the matter under consideration?_

To answer this question, first determine whether the facts to be established are such that any ordinary person can speak concerning them with reasonable accuracy, or whether they can be understood only by persons who have received special training. A landsman could well testify that a naval battle had occurred, but only a man with nautical training could accurately describe the maneuvers of the ships and tell just how the engagement progressed. A coal heaver's description of a surgical operation would establish nothing, except perhaps the ident.i.ty of the people and a few other general matters; only a person with a medical education could accurately describe the procedure. The testimony of any one but a naturalist would not even tend to prove the existence of an hitherto unknown species of animal life. A witness without technical knowledge cannot give reliable evidence on matters of a technical nature.

Then, if it is found that the witness does possess the necessary technical training, or that no previous training is necessary, still further test his ability to give reliable evidence by asking whether he has had ample opportunity for investigating the facts to the existence of which he testifies. For even a skilled player sitting in the first base bleachers at a baseball game to criticise an umpire's decisions on b.a.l.l.s and strikes is absurd; the opinion of a transient visitor to Panama on the methods used in digging the ca.n.a.l is not valuable; a traveler who has spent a single month in j.a.pan cannot draw reliable conclusions on the merits and defects of its political structure. In not one of these cases has the opportunity for investigation been sufficient to render the witness able to give reliable evidence.

A current magazine in discussing the weakness of testimony that comes from incompetent witnesses says:--

Generalizations about the tastes and interests of the age are so easy that all except the most wary fall into them, and the world is full of off-hand opinions touching the condition of society and the state of the world, which are far more conspicuous for courage than for discretion. There are very few men or women in any particular period who know it intimately enough, and with sufficient insight and sympathy, to pa.s.s judgment upon it. One hears almost every day sweeping judgments about Americans, English, French, Germans, Chinese, and j.a.panese which are entirely valueless, unless they are based on a very broad and intimate knowledge of these various peoples, a knowledge which, in the nature of things, few people possess. The charming American girl who declared that, since gloves are cheaper in Paris, American civilization is a failure, may stand for a type of interesting and piquant oracles, to be heard with attention, but under no circ.u.mstances to be followed. Americans are so familiar with the European traveler who arrives and makes up his opinion over night in regard to men, morals, and manners in the Western world and have so often been the victim of this self-confident critic, that they ought not to repeat the same blunder in dealing with other peoples.

[Footnote: The Outlook, July 20, 1907.]

In the court room, where witnesses are present and can be carefully examined by the lawyers on both sides, it is customary to apply both mental and physical tests. The witness who testifies to knowledge of some event that occurred a long time before is given a memory test; the senses, also, through which occurrences are perceived are frequently examined. But as writers and debaters in general seldom have the opportunity to apply tests of this sort to their sources of information, and as these tests are seldom important outside of the law courts, they are not taken up in detail in this book.

The second test of the source of evidence should be:--

(2) _Is the witness willing to give an accurate account of the matter?_

One important influence that may cause a witness to give false evidence is _self-interest_. Not only individuals, but social and industrial organizations, political parties, communities, and states are frequently swayed by this emotion to the extent of deliberately perverting the truth. The evidence found in newspapers and other publications is often false, or at least misleading, because it has been tampered with by those who put their selfish interests before all else. The owner of an industry protected by a high tariff would scarcely be considered a reliable witness in matters affecting tariff reform. The opinion of a railroad magnate on the subject of a compulsory two-cent rate law would not be considered as unbiased. No disinterested seeker after truth would accept the political conclusions of a newspaper owned by a politician or recognized as the organ of a certain party. In all such cases, self-interest may prompt the witness to make statements not in strict accordance with the truth. Perjury in the court room is not uncommon; falsehood elsewhere must be guarded against. The arguer should always carefully scrutinize the testimony of a witness that has any special interest in the matter for which evidence is being sought. Though the self-interest is strong, the witness may be willing to state the matter accurately; but, as long as human nature remains as it is, this willingness should not be taken for granted.

The third test of the source of evidence should be:--

(3) _Is the witness prejudiced?_

Another emotion that frequently keeps a witness from telling the exact truth is _prejudice_. Every one is familiar with instances of how this pa.s.sion warps men's morals and corrupts their judgment. If a man is prejudiced for or against a person or a system, he cannot be accepted as a trustworthy witness in matters where his prejudice comes into play. Should an economist known to favor socialism write a treatise advocating munic.i.p.al ownership of public utilities, his evidence and his reasoning would not be convincing; it would be taken for granted that he looked at the subject through socialistic spectacles. A person who sets out with the expectation and intention of finding flaws in anything usually succeeds. Though he is willing to tell the exact truth, yet because of his prejudice he is sure to see only that which will coincide with his preconceived opinions. For this reason, political speeches and intensely partisan books and papers are invariably unreliable sources of evidence even though they are not intentionally dishonest.

The fourth test of the source of evidence is:--

(4) _Does the witness have a good reputation for honesty and accuracy?_

The human conscience is so const.i.tuted that many people deviate from the truth for no apparent reason whatever. Some are given to exaggeration; some habitually pretend to know that of which they are entirely ignorant; others are so inaccurate that everything they say is open to grave suspicion. If a witness is known to have been repeatedly dishonest or inaccurate in the past, little reliance should be placed in his testimony. "Yellow journalism," which is largely the reflection of common rumor, affords constant examples of witnesses that give questionable evidence.

Ability and willingness to give exact evidence, an unprejudiced att.i.tude, and a good reputation for honesty and accuracy are the qualities that should characterize the sources of evidence. If a writer or speaker is securing testimony from friends or acquaintances, the application of these tests is not difficult. If, however, the sources are books and periodicals, his work is harder; but to be successful, he must not shirk it. When one procures evidence from books, he should investigate the character and standing of the author.

When one obtains it from signed articles in papers and magazines, he must consider both the author and the character of the publication. In the case of newspaper "stories" and editorials, one should find out on what general policy and principles the paper is conducted. A cautious arguer will always avoid, as far as he can, the use of evidence that comes from a doubtful source. If one finds that an opponent has used the testimony of questionable witnesses, he can, by exposing the fact, easily refute the argument.

NECESSITY OF STATING SOURCES. It sometimes happens that an arguer fails to state the source of his evidence. This omission is usually fatal to success. No one is likely to put much confidence in statements that are introduced by such flimsy preambles as, "A certain statesman has declared"; "I have read somewhere"; "An acquaintance told me." Not only must evidence come from sources that seem good to the writer, but those sources must be satisfactory to the audience. In the last a.n.a.lysis the audience is the judge of what is credible and what is not. Moreover, if the evidence is of great importance, or is liable to be disputed, the arguer should show in a few words why the witness is especially reliable.

B. INTERNAL TESTS OF EVIDENCE

(1) _Is the evidence consistent with (a) other evidence in the same argument; (b) known facts; (c) human experience?_

The requirement that every separate bit of evidence in an argument shall be consistent with every other bit of evidence in the same argument is too well understood to need explanation. One familiar with courts of law knows that a witness who contradicts himself is not believed. Furthermore, if the testimony of several witnesses for the same side is inconsistent, the case for that side is materially weakened. So it is in general debate: the arguer who wishes to succeed must not use evidence that is self-contradictory. His proof must "hang together"; his facts must all go to establish the same conclusion.

A flagrant violation of this principle once occurred in a cla.s.s-room debate. The speaker for the negative on the proposition, "_Resolved_, That freshmen should be ineligible for college teams," said that such a rule would deprive the freshmen of much- needed physical exercise. Later on, he said that just as many freshmen would receive injuries under this rule as without it, since they would take part in equally dangerous contests as members of freshmen teams.

This contradiction ruined his argument.

In the next place, evidence to be of any value whatever, must be consistent with what is known about the case. If an arguer is so careless as to make statements contradictory either to well- established facts or to facts easily proved, he cannot hope to attain the slightest measure of success. Only one guilty of gross neglect or absolute falsehood is likely to fall into such an error. At one time the story was circulated that, during his early life, Lincoln had been insane. In the following pa.s.sage Ida M. Tarbell shows that the testimony on which this belief was founded is inconsistent with the known facts of the case, and is, therefore, palpably untrue:--

"Mr. Thornton went on to say that he knew beyond a doubt that the sensational account of Lincoln's insanity was untrue, and he quoted from the House journal to show how it was impossible that, as Lamon says, using Herndon's notes, 'Lincoln went crazy as a loon, and did not attend the legislature in 1841-1842, for this reason'; or, as Herndon says, that he had to be watched constantly. According to the record taken from the journals of the House by Mr. Thornton, which have been verified in Springfield, Mr. Lincoln was in his seat in the House on that 'fatal first of January' when he is a.s.serted to have been groping in the shadow of madness, and he was also there on the following day."

Lincoln himself was an expert at detecting inconsistency wherever it existed. He won many of his lawsuits by the straightforward method of showing that the one or two vital statements on which the whole case of the opposition rested were false, inasmuch as they were inconsistent with well-established and incontrovertible facts. An instance of this sort is here described:--

The most damaging evidence was that of one Allen, who swore that he had seen Armstrong strike Metzker about ten or eleven o'clock in the evening. When asked how he could see, he answered that the moon shone brightly. Under Lincoln's questioning he repeated the statement until it was impossible that the jury should forget it. With Allen's testimony unimpeached, conviction seemed certain.

Lincoln's address to the jury was full of pathos. It was not as a hired attorney that he was there, he said, but to discharge a debt of friendship.... But Lincoln was not relying on sympathy alone to win his case. In closing he reviewed the evidence, showing that all depended on Allen's testimony, and this he said he could prove to be false. Allen never saw Armstrong strike Metzker by the light of the moon, for at the hour when he said he saw the fight, between ten and eleven o'clock, the moon was not in the heavens. Then procuring an almanac, he pa.s.sed it to the judge and jury. The moon, which was on that night only in its first quarter, had set before midnight.

[Footnote: The Life of Abraham Lincoln, Vol. I, p. 272. Ida M.

Tarbell. The Doubleday & McClure Co.]

An arguer should also be extremely careful to use evidence that on its face appears reasonable. Only an extremely credulous audience will accept ideas that run counter to human belief and experience. To attribute the occurrence of an event to supernatural causes would bring a smile of derision to any but a most ignorant and superst.i.tious person. To attribute to men qualities and characteristics that human experience has shown they do not possess will bring equal discredit.

No one is likely to accept evidence that contradicts his habits of thinking, that is contrary to what his life and experience have taught him is true. For this reason savage people are slow to believe the teachings of the Christian religion. For this reason it is difficult to make an audience believe that any one will deliberately and consistently work against his own interests, or follow any other unusual line of action. Evidence contrary to human experience may be true, but unless the exigencies of the argument demand its use, the arguer will do well to omit it entirely. If he is obliged to use it, he should make it appear as reasonable as he can, and also substantiate it with careful proof.

Huxley appreciated the fact that evidence, to be believed, must be in accordance with man's experience when he wrote the following:--

If any one were to try to persuade you that an oyster sh.e.l.l (which is also chiefly composed of carbonate of lime) had crystallized out of sea-water, I suppose you would laugh at the absurdity. Your laughter would be justified by the fact that all experience tends to show that oyster-sh.e.l.ls are formed by the agency of oysters, and in no other way.

The ease with which an argument that does not satisfy this requirement may be overthrown is clearly shown in the following extract from a student's forensic:--

To say that the Cuban reconcentrados sunk the _Maine_ in an effort to embroil the United States in a conflict with Spain is the veriest foolishness. There is not one sc.r.a.p of doc.u.mentary evidence to show that such was the case. Moreover, such an act would be unparalleled in the annals of history. It is unreasonable, contrary to all experience, that those oppressed people should have brought disaster, involving the destruction of property and the loss of many lives, upon the very nation that they were looking to for a.s.sistance.

(2) _Is the evidence first-hand or hearsay evidence?_

It is universally recognized that hearsay evidence is unreliable. A narrative is sure to become so garbled by pa.s.sing from mouth to mouth that unless a witness can testify to a fact from his own personal knowledge the evidence he gives is worthy of little credence. There is sufficient chance for error when the person who witnessed the event relates the account himself; if the story is told by a second, and perhaps by a third person, it is likely to reflect but little of what really happened. Every one is familiar with the exaggerations of common rumor; it distorts facts so that they are unrecognizable. The works of Herodotus are untrustworthy because he frequently believed hearsay evidence. Since second-hand evidence both fails to establish anything worth while, if allowed to stand, and is easily overthrown even by a very little first-hand evidence, an arguer will do well to follow the custom of the law courts, and, as a rule, exclude it altogether.

(3) _Can the evidence be considered as especially valuable?_

(a) _Hurtful admissions_ const.i.tute an especially valuable kind of evidence. Since men are not wont to give evidence detrimental to their personal interest unless impelled to do so by conscientious scruples, any testimony damaging to the one who gives it is in all probability not only truthful, but also the result of careful investigation. When a practising physician admits that half the ailments of mankind are imaginary or so trivial as to need no medical attention, he is making a statement that is likely to injure his business; for this reason he is probably stating the result of his experience truthfully. If a railroad president says that in his opinion government supervision of railroads will benefit the public in the matter of rates and service, it may be taken for granted that he has given his honest belief, and that his natural reluctance to surrender any authority of his own has kept him from speaking carelessly. If a member of the United States Senate admits that that body is corrupt, and selfish, and untrustworthy, he is lowering his own rank; therefore it is reasonable to believe that he is speaking the truth according to his honest belief.

The following is an example of this kind of evidence:--

It was stated during the Manchurian campaign that the Jewish soldiers, of whom Kuropatkin had about 35,000, not only failed to hold their ground under fire, but by their timidity threw their comrades into panic. But good evidence can be cited from the correspondents of the _Novoye Vremya_, an Anti-Semitic organ, to the effect that among the Jews were found many "intrepid and intelligent soldiers,"

and that a number of them were awarded the St. George's cross for gallantry. [Footnote: The Nation, June 11, 1908.]

It is hardly necessary to add that one who places especial reliance on this kind of evidence must be sure that the admission is _really_ and not merely _apparently_ contrary to the interest of the one who gives it.

(b) Another particularly valuable kind of evidence is _negative evidence_, or the _evidence of silence_. Whenever a witness fails to mention an event which, if it had occurred, would have been of such interest to him that he might reasonably have been expected to have mentioned it, his silence upon the matter becomes negative evidence that the event did not occur. For many years no one suggested that Bacon wrote the Shakespearean plays; this absence of testimony to the belief that Bacon wrote them is strong evidence that such belief did not exist until recently, a fact that tends to discredit the Baconian theory of authorship. The fact that in the writings of d.i.c.kens and Thackeray no mention is made of the bicycle is negative evidence that the bicycle had not then come into use. That Moses nowhere in his writings speaks of life after death is negative evidence that the Hebrews did not believe in the immortality of the soul. If admittedly capable and impartial officials do not inflict penalties for foul playing during a football game, there is strong presumption that little or no foul playing occurred.