The theory and practice of argumentation and debate

by Victor Alvin Ketcham

Thus the fact to be used is traced through the statement of a fellow-student, through the editorial in the newspaper, through the article in the North American Review, back to its original and trustworthy source—the Report of the Treasurer of the United States. In this manner every fact presented must be traced to its most trustworthy source. In quoting the opinions of individuals the same principle should be applied. The greater the learning, ability, and reputation of the person quoted, the greater is the weight attached to his opinions.

In almost every branch of human endeavor and in every field of knowledge there are a few men who possess especial ability. By common consensus of opinion these men are regarded as authorities and their statements of fact or judgment are accepted as the most trustworthy. For example, the statements of Ely, Seligman, and Seager in the field of economics, and the statements of J. P. Morgan, and Andrew Carnegie in the field of industry and finance, are regarded as good authority. In chemistry the statements of Dr. Ira Remsen would be considered good, while in regard to psychology one could do no better than to quote the opinions of Hugo Münsterberg. Regarding the wireless telegraph, Marconi would be the most reliable source, while in the field of aërial navigation the opinion of the Wright brothers could be quoted as the most reliable. Instances of reputable sources of evidence could be cited sufficient in number to cover many pages, but the few here suggested will serve to illustrate the class of authority to which all points of evidence should be traced.

2. A person quoted as authority must be unprejudiced, in full possession of the facts, and capable of giving expert testimony on the point at issue.

In the preceding section reliable sources of evidence have been indicated in a general way. It is, however, by no means possible in the treatment of all subjects to cite authorities so universally accepted. The opinions of persons who are not known to the general public may be given weight by means of their official position, their special work or investigation in any line, or by the favorable statements of recognized authorities regarding them or their work. As previously suggested, Who’s Who in America, is a storehouse of information regarding such people.

An opinion or even a statement of fact is not likely to be looked upon with favor unless it comes from an unprejudiced source. It is not so much the question of actual prejudice existing in the mind of the person quoted as it is the surrounding circumstances which would naturally tend to cause prejudice. For example, the statement of John D. Rockefeller, in regard to the beneficent effect of monopolies on trade and commerce, might be perfectly sincere, but since John D. Rockefeller has a financial interest in the maintaining of a monopoly, it would not be advisable to quote his statements in their favor. Such statements are not only easily refuted but they lack weight because they do not appear to come from an unprejudiced source. In like manner the President of the Brewers’ Association would not be accepted as authority on any matter connected with the prohibition of the liquor traffic. From the very circumstance of his position he is presumed to be prejudiced against such prohibition. The person cited as authority should have no financial interest in the subject on which he is quoted. He should be in a position to be unprejudiced.

The person quoted as authority must be in full possession of all the necessary facts. Very often this knowledge of facts may be presumed from the position which the authority occupies. The Secretary of the Navy is presumed to be in full possession of all the general facts concerning his department. The captain of a battleship would be presumed to know all the essential facts in regard to his ship. An engineer on the Panama Canal would be presumed to be in a position to know, and actually to know, facts connected with the duties of his position. The authority quoted must be in full possession of the facts which he is quoted to prove, or upon which his opinion is based.

Regarding the capability of an authority to give expert evidence much has been said. It is well to remember, however, that the opinion of fact or judgment must be in the field of the authority’s professional knowledge. The most eminent chemist in the United States would not be considered proper authority on an economic question; much less would the most eminent economist be considered good authority on some problem in chemistry. The President of the United States might be quoted as the highest authority on the political situation, while his opinion on some technical problem of engineering would fall before a counter opinion by an eminent engineer. In quoting an authority to establish an important point in evidence it is often advisable to show directly that he is unprejudiced, in full possession of the facts, and capable of giving expert testimony.

3. Evidence should be examined to determine whether there are attendant circumstances which will add to its weight.

It often happens that evidence which is good in itself is given still greater weight by some special circumstances. The law recognizes and gives much weight to “Declarations against Interest,” and such declarations are as valuable in argumentation as in law. A declaration against interest is a statement of fact or opinion made by a party before the subject became a matter of controversy, which statement is now against the interest of the person making it. To illustrate, let us suppose that John D. Rockefeller had made a statement opposing the formation of monopolies. At present he wishes to argue in favor of monopolies. The statement which he previously made and which was an expression against monopolies now becomes a “declaration against interest.” Likewise any statement made in regard to a subject before the party making it becomes interested therein financially may be used against him when the matter becomes one of controversy and he wishes to take a different position.

Of equal value is the opinion frankly expressed, by one whose personal interests are opposed to the statement made. Such statements are sometimes made by public spirited men in the interests of right and justice. An illustration in point is that of the banker who admitted that the postal savings bank would be a benefit to the people at large, although he recognized the fact that it would injure the business of the private banker, a class to which he himself belonged. Such statements are of the utmost importance when they come from leading members of the class against which they constitute admissions. Statements made by persons who express their views in accordance with what appears to them to be right and without the knowledge that they are talking against their own interests may likewise be used as admissions. Such were the statements of a citizen who favored the building of an elevated railroad in his city. He believed that such a highway would relieve the congested condition of the streets and thus benefit the public. When the route for the proposed road was definitely located he found that it would result in irreparable damage to his private business. Although he at once changed his view on the subject, his previous admissions were used against him with such effect that his new arguments had no weight in the final determination of the matter.