CHAPTER IV

EVIDENCE

The analysis of the question has revealed the main issues. The next step in the argumentative process is to prove the truth of these main issues by producing evidence. Evidence consists of the material by which the truth or falsity of a proposition is proved. It is an error to use the terms “proof” and “evidence” as synonymous. Proof is the result or effect of evidence; evidence is the material of proof. A thing is not proved until sufficient evidence has been produced to establish it. The most accurate logicians make this distinction and it is well to observe it in the study of argumentation. A given fact is not proof of the truth of a statement unless it alone is sufficient to establish such truth; otherwise it is merely evidence tending to show that the statement is true. This distinction should be kept clearly in mind, and no fact should be offered as complete proof when it is only evidence tending to support a given proposition.

The student is now confronted with the necessity of establishing his proposition by presenting evidence in support of the main issues. The first problem which naturally comes to him is: “Where shall I go to find this evidence?” In answering this question the student should consult carefully, one by one, each of the following:

I. Sources of evidence:

_1. Personal knowledge._

Before turning to outside sources the student should carefully examine the contents of his own mind to determine just how much he really knows about the subject. He should, however, distinguish between exact knowledge and mere conjecture. His exact knowledge, gained from whatever source, is perfectly valid from the standpoint of evidence providing it can be proved. The line between exact knowledge and mere conjecture is determined by the ability of the student to lay his hands upon sufficient evidence to prove the thing that he believes to be true.

_2. Personal interviews._

If the question is a local one personal interviews are both practicable and valuable. Interviews with persons who are connected in some way with the subject of dispute, or who are in a position to have exact knowledge of the subject-matter, or who are taking an active part in the local discussion of the subject, are a most important source of evidence. Interviews with such persons not only give the student facts, reasons, and opinions, but they usually reveal other sources to which he can go directly. For example, in a local debate on the question of whether the city, or the street railway company should bear the expenses of building a bridge which they used in common, the debaters obtained personal interviews with all the city officials having anything to do with the bridge, and with the officials of the street railway company. Prominent citizens and business men of the city were also interviewed. These interviews were productive of a large amount of material in the form of facts, reasons, illustrations, opinions, and references to other sources of material. In the discussion of any local question the debater will usually find the parties concerned willing, and even eager to give him “ammunition” for the debate.

In collecting evidence on questions which deal with the problems of commerce, taxation, economics, politics, and education, the student will usually find some men whose opinions are entitled to careful consideration and with whom interviews may be arranged. Whether these men are quoted as authority will, of course, depend upon their known reputation in the branch of knowledge upon which their opinion is asked. Even if the debater does not think it best to quote the person interviewed, he may gain from him much valuable help. Arguments reasoned out from the facts of a case depend for their worth upon the validity of the reasoning process and not upon their source. Therefore the arguments of any well-informed, intelligent person, if based upon facts and logically sound, can be utilized. Moreover, such persons are often able to give information regarding sources of evidence which may have escaped notice. The college student would do well to consult the members of the faculty whose work would make them familiar with the subject-matter of the argument. The student should by no means pass lightly over this source of material. In fact, such sources should be exhausted before a more extended search for evidence is entered upon. Furthermore, a discussion of the subject with these well-informed people will beget new ideas and give a breadth of view regarding the subject which will be helpful in subsequent investigation.

_3. Personal letters._

After the student has gained some knowledge regarding the most eminent authorities on the subject under discussion, he may feel at liberty to address some of them with a personal letter. This letter should be brief and to the point, stating just what is wanted. If questions are asked they should be brief and plain. The use to which the reply is to be put should be stated.

If the question is one with which national, state, or municipal officials are concerned personal letters may be written to them. If this is carefully done in accordance with the foregoing suggestions, a prompt reply is almost always assured. An opinion expressed in a personal letter from a national or state official, or any information given by him, is usually looked upon with considerable respect.

Still another class of men to whom personal letters may be written with profit consists of the well known officials of large sectional and national associations such as the American Bar Association, the American Federation of Labor, and the National Manufacturers Association. The officials of these and other similar associations are usually well pleased to be consulted upon the questions in which their opinions are regarded with respect. Although the debater should not carry on a correspondence campaign for material, yet he should not hesitate to write for facts and opinions which are of vital importance.

_4. Current literature._

Current literature offers the most prolific field of information on subjects of general interest. This source of material is always available to the debater. His first efforts should be directed to finding out what this field contains that bears directly on the subject. With this object in view he should consult _The Reader’s Guide_, _Poole’s Index_ and the _Annual Library Index_. Here he will find all the important magazine articles that have been written on any subject. The title of the article, the name of the writer, the magazine in which it is found, together with the date, volume, and page, are given exactly. This opens a great storehouse of information. In consulting these guides to periodic literature the investigator should exercise his ingenuity as well as his imagination in determining under what topics he will find his material listed. In investigating the proposition “Resolved, that Congress should immediately provide for an increase in the navy,” the student must not be content with merely looking up the articles found listed in the guide under the topic “Navy.” He should also look under “Battleships”, “Warships”, “Dreadnoughts”, “International Peace”, “Foreign Affairs”, etc. At the end of these lists cross-references to related subjects will be found and these should also be consulted.

The student should go over the list of articles carefully and make out a bibliography[2] of magazine references. Titles of all articles which appear to have a bearing on the subject should be taken down in full. This process of going over the lists in search of pertinent articles should be repeated from time to time throughout the investigation, because as the student’s knowledge of the subject broadens he will get more clearly in mind the exact nature of the information which he requires. The bibliography will save much time in getting at the most valuable material in current literature.

Footnote 2:

A bibliography (as the term is here used) is a list of books and periodicals on any one subject with exact references to volumes, page, etc.

The student can now select from the great number of articles before him those which appear to be most valuable. The most valuable articles are those which (a) bear directly upon some main issue of the question and (b) are written by recognized authorities on the subject. If the writer of any particular article is unknown to the student he should consult “_Who’s Who in America_.” Here are arranged in alphabetical order the names of all the men in America who have attained distinction in any line of endeavor. In connection with each name there is given a brief biography which sets forth the positions that individual has held, honors which have been bestowed upon him, important work in which he has been engaged, and any other facts which might tend to give weight to his utterances. Foreign authorities should be investigated by consulting the encyclopedias, the Who’s Who volume (if available) of the particular country to which the writer belongs, or by referring to other prominent writers. Throughout the entire investigation “_Who’s Who in America_” should be consulted as an authority on the standing of men to whose work the debater wishes to refer. This method of using “_Who’s Who_” and the bibliography brings the student directly to the best sources of material which can be found in current literature.

As indicated above, the real criterion of the value of an article in a magazine is the standing of the man who wrote it. However, certain periodicals have come to be looked upon with such respect by students and scholars that all articles appearing in them are given considerable weight. This reputation which is sustained by certain publications results from the care with which the editors have selected the material put into the magazine. They have been careful to allow only capable writers to contribute to their periodicals in the past, and, we may assume (although this is sometimes a violent assumption) that this careful supervision will continue in the future. Moreover, the editorials of these magazines are looked upon as good authority. For the convenience of the student the following list of magazines is suggested as reliable sources of evidence.

(1) _The North American Review._

(2) _The Literary Digest._

(3) _The Independent._

(4) _World’s Work._

(5) _Review of Reviews._

(6) _The Annals of the American Academy of Political and Social Science._

(7) _Columbia University Studies in History, Economics, and Public Law._

The last two publications are somewhat different from the others mentioned in the list, but they are included because they are important and are usually available in libraries having the other publications enumerated. This list is not intended as a complete and exhaustive list but merely as a suggestion to the student in search of material. It is not intended to depreciate the value of any publication not included in the list. However, the student should beware of relying upon material found in any magazine merely because the publication poses as a magazine instead of as a newspaper or story book. Some of the popular magazines which appear to be manufactured for the sole purpose of being sold, make an attempt at sensationalism rather than truth. Such periodicals should never be relied upon as authority.

Another source of evidence found in current literature is the technical and professional magazine. Almost every trade and profession has one or more reliable magazines. In the fields of medicine, law, banking, contracting, engineering, etc., are many periodicals. Each offers articles by reliable writers on almost all phases of the particular branch of learning to which the magazine is devoted. Prominent among the technical magazines that may be quoted as authority is the Engineering News. This periodical offers much valuable material on all the important engineering problems of the day.

Magazine articles, outside of the technical and professional magazine, are usually written for the layman; hence the subjects are usually presented in a manner easy to understand. This is especially important to the student at the beginning of his investigation when his knowledge of the subject is limited. Simplicity of treatment and accuracy of statement combined with an almost boundless range of subject-matter make current literature a most valuable source of evidence.

_5. Standard literature._

Under this head are included all the reliable encyclopedias, reference works, text-books, and books on special subjects written by experts and authorities. For brief, accurate, and authoritative articles of a general character, the encyclopedias are most valuable. The best works of this class are _Britannica_, _Chambers’_, _Nelson’s_, _Johnson’s_, _Appleton’s_, _Appleton’s Annual Cyclopedia_, and _Bliss’ Encyclopedia of Social Reform_. Text-books and special works by authorities on all subjects are very numerous. For this source of material it is best to consult the catalogue of a library. Here will be found under the author’s name all of his works that are in the library. After the student has found out by personal interviews, reading current literature, etc., who are the most reliable writers on the subject in hand, he should always consult this index of authors to determine whether any of their books are available. The catalogue of the library usually classifies the books also according to subject-matter. Therefore by consulting this catalogue all the books on this particular subject contained in the library may be made accessible. Here again, as in the case of the index to periodic literature, the investigator must use his ingenuity in determining under what heads he may find his most valuable material.

_6. Special documents._

(1) _Reports and pamphlets issued by organizations._

In order to gain access to this sort of material it is usually necessary to write to the headquarters of the organizations. In most cases their reports and other printed matter may be had for the asking, although in some cases a charge is made. The student, however, can usually obtain sufficient material of this character without any cost to himself other than the small outlay necessary for postage. In the larger schools and colleges it is now becoming customary for the debating teams to have letter heads printed. These state the name of the institution or of the debating league to which the institution belongs, the names of the members of the team, and the question for debate. While this procedure is unnecessary for class debates or written arguments, or even for society or college debates, it is at least desirable in the preparation for an intercollegiate debate such as is held between members of large debating leagues. By this use of letter heads in writing to the officials of organizations, as well as to private individuals, a full and more careful response is almost always secured. However, in most cases a request for reports or other material, with a statement of the use to which they are to be put, is all that is necessary to bring a prompt reply. Almost all the important trades and professions have national organizations which are ready to aid in the distribution of knowledge in their several spheres. Among organizations of a professional character may be mentioned the American Bar Association, the American Chemical Society, and the National Education Association. Among industrial organizations, the American Federation of Labor, and the National Manufacturers Association are probably the most important.

Organizations having for their object the bringing about of certain reforms in our social or political life are always willing to send material for use in the discussion of questions in which they are interested. Among these may be mentioned the International Reform Bureau, the Anti-Saloon League, the Lake Mohonk Conference on International Arbitration, the American Peace Society, and the New York Reform Club. It is well worth while for the student who is investigating any of the questions in which these associations are interested to write them for material.

In special branches of learning there are various organizations which publish both reports of their meetings and special reports on subjects connected with their work. The American Historical Association, and the American Economic Association belong to this class. Other organizations of this character will be brought to the attention of the student before he has advanced far in the study of any proposition.

(2) _Reports and documents issued by the government._

Government documents and reports, especially those issued by the Federal government, are among the most valuable sources of evidence. The authors or compilers of these reports are men whose official positions enable them to obtain accurate information. Furthermore, these men have usually passed a civil service, or other examination, and thus demonstrated their ability to perform the tasks assigned; or on account of favorable reputation have been elected or appointed to fill the positions for which they are well qualified. Their action is taken purely as governmental agents and, from the nature of their office and the requirements of public opinion, that action and all information gathered conform approximately to the facts. For these reasons governmental reports and documents are looked upon as the highest authority on the subjects with which they deal, and anyone who argues can offer no better evidence than a basis of fact backed up by definite references to official government documents.

One of the most useful documents of this class is the _United States Census Report_. This report contains not only the _population statistics_ but also other funds of information even more valuable to the student. In it there are vital statistics, statistics on labor, manufacturing, commerce, and a multitude of other subjects which the student dealing with any economic or commercial proposition cannot overlook. If accurate information is required regarding any phase of our national growth or present activity the census report should be consulted before any other source of evidence.

Another most important source of evidence is the _Report of the United States Industrial Commission_. This report comprises nineteen volumes, the last of which (Vol. 19) contains valuable material, together with the recommendations of the commission, in regard to almost all the leading industrial and economic questions which are now being discussed. The report as a whole covers the entire industrial field in this country and offers a reliable and exhaustive fund of information.

In the _Congressional Record_ can be found discussions, both affirmative and negative, of all the public questions which have come before either branch of Congress. This source of material is very suggestive but it is not always trustworthy. It should not be quoted in itself as an authority. The mere fact that one may refer to a certain volume and page of the _Congressional Record_ on which a certain statement appears is no proof of the truth of that statement. The material which it contains is mainly the reports of speeches. The record is official and authoritative so far as concerns what was said in those speeches. However, the value of the thing said depends upon the man who said it. Therefore, the debater should quote Representative Douglas, or Senator Burton as saying so-and-so which is found in such a volume and on such a page of the _Congressional Record_. With this caution in mind, viz., that it is the man who is quoted and not the mere fact of its appearance in the _Congressional Record_ that gives weight to a statement, the student should utilize this source of evidence. The index of these records is decidedly awkward for a beginner, but the material contained therein is so important that some little time may well be spent in making the acquaintance of the indexing system. The _Congressional Record_ is indexed under three heads, (1) names, (2) subjects, and (3) bills by their official numbers. A great mass of material will be found under subjects, but after the student has accustomed himself to using the index he can readily find the material which he desires to read. The _Congressional Documents_ which contain reports from the executive departments and the legislative committees are divided for each session of Congress into six groups: (1) _Senate Executive Documents_, (2) _Senate Miscellaneous_, (3) _Senate Reports_ (of committees), (4) _House Executive Documents_, (5) _House Miscellaneous_, (6) _House Reports_ (of committees). A _Document Index_ for each session of Congress will be found in connection with these volumes.

Any school or library, or in fact any individual, may obtain valuable lists of government publications by writing to the Library of Congress or to the Superintendent of Documents. From time to time the Library of Congress publishes special books and articles on such subjects as Taxation of Inheritance, Tariffs of Foreign Nations, Capital and Labor, and many other questions of national importance.

In addition to the publications of the national government, reports issued by the various states and municipalities should be investigated. For example, in discussing a question of taxation the amount of tax derived by each state from a certain source may become important. If this information cannot be found already compiled, it may be obtained by writing to the secretary, treasurer, or auditor of each state and asking for the report in which such information is published. If it be a source of taxation used only in a part of the states, the student should compile a list of the states in which it is used and write to the officials in those states only.

In the discussion of municipal problems, such as municipal ownership of public utilities, the commission form of city government, etc., it is well to write to the cities in which these plans have been tried and get such reports as will show the results.

A careful investigation of all the sources here set forth will yield information sufficiently broad and varied for the argumentative discussion of any subject. However, the student may well consult other text-books on Argumentation and Debate for the purpose of getting suggestions regarding the sources of material which will be useful to him. Books of briefs for debates and reports of debates are published, which give helpful suggestions regarding material or evidence on many of the most important questions. As advancement is made in the practical work of investigating subjects for argumentative treatment, facility in utilizing the sources of evidence will be acquired. At first the time spent in the investigation of some sources, especially standard literature and government documents, may not appear to yield the practical results which time well expended ought to yield. Here a word of caution is necessary, for time spent in this manner should never be regarded as wasted. It is not wasted, because the student is acquiring the power to investigate subjects on his own responsibility, and the ability to skim rapidly over large masses of material and select only the things that are really useful. It is only after long periods of such diligent work that the student can feel himself master of the resources of great libraries, and an expert in the use of the sources of evidence.

SUMMARY OF THE SOURCES OF EVIDENCE

1. Personal knowledge.

2. Personal interviews.

3. Personal letters.

4. Current literature.

5. Standard literature.

6. Special documents.

(1) Reports and pamphlets issued by organizations.

(2) Reports and documents issued by the government.

II. Recording evidence.

After an acquaintance with the sources of evidence is gained the necessity for some orderly method or system of taking notes becomes apparent. This is the next important step in argumentation. The investigator should not rely upon his memory. Notes should be taken on every source of evidence discussed in the preceding section. An idea rarely becomes our own until it has been expressed in our own words. As ideas on the subject for discussion occur to the debater’s mind they should be recorded in order that they may be at hand when required. Opinions expressed and information acquired in personal interviews should be recorded either during the interview or immediately after. It is preferable to devote one’s attention exclusively to an interview, and then record the results as soon as possible after its termination. Even the ideas expressed in personal letters and extracts from them should be written down by the student in order that he may have them in convenient form for reference. The futility of reading without taking notes is apparent at first thought. Notes should be taken at the time the reading is done. All important matters of fact and all quotable matters should be recorded during the reading. Even if a particular fact does not appear to bear directly on the phase of the subject under discussion, it should, nevertheless, be recorded. It may later prove to be valuable evidence.

The notes taken should be full and complete. This requirement applies to the substance of the material and not to its form. In most cases the reader should be able to condense the contents of a page into a few words. The point or points which the writer regarded as vital should be grasped by the reader and put down in a brief note. Statistics found in different places should be assembled and reduced to tabular form. The student must not only read, but he must think as well. New ideas, new combinations of circumstances, new relations made evident by grouping facts should all be carefully investigated and noted. Reading should be an intelligent process, not mere drudgery. The reader should assimilate, not merely store up, the knowledge gained from books.

In the recording of evidence the following rules should be strictly observed:

_1. Use small cards or sheets of paper of uniform size._

A note-book or large sheets of paper should never be used. To do so is to invite confusion. With several points on one sheet of paper or in a note-book and recorded in the order in which they were found in the reading, the student is not left free to group the ideas or points to form his argument; no classification is possible, and the notes taken become mere masses of material. The best form in which to record material is by the use of the ordinary filing cards which may be obtained at almost any book store. These cards should be about three by five inches in size and of fairly heavy stock. Ruled cards with a red line at the top are the kind most frequently used. If these cards cannot be obtained, small pieces of paper of this same convenient size should be used.

_2. Place only one fact or point on each card._

Never put more than one fact or point on the same card. Even though the facts to be recorded are intimately related in their present position, the reader should use a separate card for each. When the investigator is ready to use these facts the relation may be unimportant or may be entirely changed by the manner in which he wishes to use them. One statement may be used to support one argument, while another may be used to support an entirely separate argument. Furthermore, when this material is utilized in constructing the brief, the student must be left free to arrange his material in the most logical manner. To put more than one point on a card greatly hampers this work.

_3. Write on only one side of the card._

The handling of these cards becomes a very awkward process if writing is placed on both sides. Otherwise the process is simplicity itself. To depart from this rule in a single instance may involve the loss of an important point of evidence. This point may remain forgotten on the back of a card used frequently.

_4. Express the idea to be put on the card in the simplest and most direct terms._

In the reading, an idea should be considered only in its relation to the reader’s present purpose. When this view is taken the condensation of lengthy articles into a few terse expressions becomes an easy matter. Moreover, it trains the reader to grasp the point, and to express that point in the simplest and most direct manner. This training enables the reader to cover a much wider field than would otherwise be possible.

_5. Each card should be complete in itself._

By a strict application of Rule 4 the student ought soon to acquire such facility in condensation that each card will be complete in itself. It is very awkward to have one idea or point written on several cards. When such an arrangement cannot be avoided the cards should, of course, be lettered or numbered to indicate their proper order. These cards should be placed by themselves in company with other like series and kept separate from the single cards. Some manner of distinguishing such series of cards should be devised. The first series which it is necessary to make in order to record a complete point, or idea, or argument may be marked A1, A2, A3, etc. The second series may be marked B1, B2, B3, etc. While this method may be adopted in unusual cases, the general rule should seldom be departed from. By diligent efforts at intelligent condensation, almost every point, idea, fact, or argument may be put upon a single card. The observance of this rule will insure a good command of the material on the part of the investigator and will reduce the evidence to convenient form.

The same rule should apply to the use of quotations. Seldom if ever should a lengthy quotation be used. If some passages are especially clear and forcible they should be quoted exactly and put in quotation marks. Omissions should be indicated by the use of dots, thus: ... Condensations by the student, included in the quotation, or any comments or explanations, should be enclosed in brackets, [thus].

_6. Material for refutation should be preceded (at the top of the card) by an exact statement of the argument to be refuted._

In some cases a single word or phrase may be sufficient to indicate the argument to which the refutation is intended to apply, but in most cases this argument should be indicated fully by means of a complete statement. This condensing of the arguments of the opposition into brief, intelligible statements will also be of great use when the material is put into either the main argument or the rebuttal.

_7. The main issue or subject to which the evidence relates should be stated at the top of the card._

The subject stated at the top of the card should represent exactly the subject-matter on the card. If this subject-matter comes clearly under one of the main issues which the analysis has revealed this main issue may be stated at the top of the card as its subject. If, however, the student is unable to determine exactly under what main issue the fact recorded on the card will come, he should state a subject at the top of the card which will indicate precisely the material found upon it. The classification of the card can then be left to a later part of the process. In investigating a subject in which the main issues have been determined to be (1) Necessity, (2) Practicability, and (3) Justice, a card which states one of the evils which the proposed plan is designed to remedy should not be marked “Justice;” it should be marked “Necessity,” because it is this particular evil and like evils which make the adoption of the proposed measure necessary.

If the card relates to some special topic that the main issue is too broad to identify, then that special topic and not the broad main issue should be stated at the top of the card. For example, a card coming under Necessity may still more appropriately be classed under Political Influence, because that title more nearly indicates the evidence stated on the card. Therefore the subject should be Political Influence. Later, when the cards are being used in the construction of the brief, this card may be placed with others under the title Political Influence and then all the cards under this topic placed with those covering other topics under the head of Necessity.

_8. The source from which the evidence is taken should be definitely stated at the bottom of the card._

This should be done at the time the cards are written out. Otherwise the reference when wanted, either cannot be found or can be found only with great loss of time. The exact reference is important not only to show definitely the source of authority from which the evidence is taken, but also to enable the student to return to the same source for further details in case they become necessary. In the case of a letter or a personal interview the name of the authority consulted should be given together with the date of the letter or the time and place of the interview. A magazine article should be referred to by the name of the magazine, with the volume and page. The name of the writer should also be given unless the article is an editorial, in which case that fact should be stated. A report or document in several volumes should be quoted by volume and page. Books should be referred to by their author, title, and page.

The following diagram shows the form in which evidence should be recorded:

┌────────────────────────────┬───────────┬────────────────────────────┐ │ _Subject_ │ │ _Authority_ │ ├────────────────────────────┴───────────┴────────────────────────────┤ │ │ │ _Evidence_ │ │ │ │_Source of Evidence._ │ │ │ └─────────────────────────────────────────────────────────────────────┘

For example, a student in preparing for a class debate on the tariff question handed in a number of cards on the necessity for protection, of which the following is a sample:

┌──────────────────────────────────┬──────────────────────────────────┐ │ _Subject_: │ _Authority_: │ │ _Protection not needed._ │ _Richard T. Ely._ │ ├──────────────────────────────────┴──────────────────────────────────┤ │“Our quondam infant industries have for the most part, attained a │ │very vigorous maturity, and in some instances have become belligerent│ │and prone to monopolistic bullying.” │ │ │ │_Source_: Outlines of Economics, p. 312. │ └─────────────────────────────────────────────────────────────────────┘

SUMMARY OF THE REQUIREMENTS FOR RECORDING EVIDENCE

1. Use small cards or sheets of paper of a uniform size.

2. Place only one fact or point on each card.

3. Write only on one side of the card.

4. Express the idea to be put on the card in the simplest and most direct terms.

5. Each card should be complete in itself.

6. Material for refutation should be preceded at the top of the card by an exact statement of the argument to be refuted.

7. The main issues or subjects to which the evidence relates should be stated at the top of the card.

8. The source from which the evidence is taken should be definitely stated at the bottom of the card.

III. Selecting evidence.

All the reliable evidence obtainable should be collected before the selection of the exact evidence which is to go into the argument is begun. If the student has confined his collecting to the sources of evidence suggested in the first section of this chapter, the presumption will be in favor of its reliability. This presumption may be strengthened and in some instances turned into certainty by a selection made in accordance with the rules which it is the object of this section to present.

It is of the utmost importance that a large amount of evidence from which to construct the brief and argument be available. It is only in this way that the strongest evidence obtainable can be brought to the support of the argument. All the evidence used must be relevant but not all the evidence that is relevant need be used. The following rules should be observed in the selection of evidence:

_1. The evidence must come from the most reliable source to which it can be traced._

All the evidence collected must have back of it some reliable source, as indicated in the discussion of Sources of Authority. The more trustworthy this source the more valuable is the evidence and the greater the weight given to it. Therefore “the evidence must come from the most reliable source to which it can be traced.” Every fact offered in evidence comes from some definite source. If this source cannot be found the fact should be discarded as worthless. To illustrate, in the investigation of a subject, a fellow-student may know some fact which is a most important piece of evidence in your favor. He may tell you about this fact, but you would not think of going into the debate and quoting one of your fellow-students as authority. Therefore you will at once ask the student from what source he obtained knowledge of the fact. He may reply that he has seen it in a newspaper article. But since a newspaper is usually of little value as an authority, you cannot rely upon its statement. Therefore you inquire from what source the newspaper obtained it. By consulting the newspaper it is found that the statement is made in an editorial which comments upon an article found in the _North American Review_. You must then consult the number of the _North American Review_ to which reference is made. This is fairly reliable, and anyone would feel justified in quoting it as the source of his evidence, although he would not feel justified in quoting the statement of a fellow-student or the statement of a newspaper.

If the statement is one which is an opinion of the editor of the _North American Review_, or if for any other reason it cannot be traced back of this source, _North American Review_, volume and page, should be quoted as the source of the evidence. But suppose that the statement can be traced to its original source. To be more concrete, let us assume that the statement is to the effect that there is a surplus of over one million dollars in the United States treasury. For such a statement the _North American Review_ is not the most reliable source. In this case the most reliable source is the _Report of the Treasurer of the United States_, which can be found in almost any library. When this fact is located the student should make an exact statement of the amount of the surplus and refer to the _Report of the United States Treasurer_.

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.

It very often happens that a well known authority frequently used by the opponents of a proposition has changed his opinions or expressed himself more definitely in such a way as to favor the speaker’s contentions. Advantage should always be taken of such a state of affairs. It is a most strategic move to be able to quote an opponent’s authority against him. One should be sure, however, that the authority quoted is such as will be accepted. Otherwise it is better to attack the validity of this authority.

The above suggestions and illustrations are offered purely by way of inducing the student to keep a sharp lookout for points in his favor. There are many ways in which the attendant circumstances may be used to give greater weight to the evidence offered.

_4. The selection of evidence must be fair and reasonable._

An advocate of any cause, public or private, must have as a basis for his argument a genuine regard for right and justice. Therefore he is bound to exercise due care in making sure that the selection of evidence is fair and reasonable. No one who argues can gain any permanent advantage from the use of unfair methods. In using quotations from authority be sure that the words used indicate exactly the position of that authority. By skillful omissions a reputable authority may be made to defend almost any position. In the use of statistics the temptation to juggle is sometimes strong. Statistics, by skillful combinations and omissions, can be made to prove an absolute lie. In discussing the income from a kind of state tax which is utilized in all the most important states in the Union, the student who selected the states of Nevada, South Dakota, and Rhode Island to show that the income derived from the tax was a substantial source of revenue, must have succeeded only in proving to his audience that he had had great difficulty in finding states in which the tax had proved to be a success. Had he been able to produce statistics to show that Massachusetts, New York, Pennsylvania, Ohio, Illinois and other large and populous states were using his form of taxation with success, his chance of persuading his hearers would have been incalculably increased.

Not only must evidence be fairly selected but it must be reasonable as well. No statement which is contrary to the usual experience of the individuals addressed should be made unless it is based upon indisputable authority. Facts outside the pale of usual human experience are always regarded with distrust. Abnormal conditions, such as the existence of unusual misery or vice among certain classes, oppression, glaring social, industrial, or political evils, must always be kept within the bounds of possibility and based upon reliable authority. The temptation is often strong to cite instances on account of their sensational character and the probable striking effect upon the audience or readers. Such material is sometimes very important, but if it even approaches the border of impossibility it should be fortified by the strongest evidence.

The value of certain evidence may be greatly increased if it can be shown to be reasonable. If surrounding circumstances can be introduced to show that the evidence is either cause or effect and therefore something naturally to be expected under the conditions stated, it will be accepted almost without question. All evidence should be carefully considered from the two standpoints of fairness and reasonableness. To offer unfair evidence is dishonorable. It is the method of the swindler and the trickster. It is especially reprehensible in the student of argumentation, whose first duty is to uphold the truth.

_5. The position and arguments of the opposition should be taken into consideration._

Argument implies opposition. It may not be active opposition, it may be only passive. Arguments advanced for the purpose of inducing a change meet conservatism, prejudice, and the natural feeling of distrust with which any change is contemplated. These obstacles to success must be met squarely. It is by this means alone that they can be overcome. In the analysis of the question the necessity of finding the main contentions on both sides was made plain. We have now reached a point at which these contentions become of great importance. The arguments of the opposition must never be disregarded. Many important advantages besides the economy of time and material, come from the selection of such evidence as will uphold the constructive argument and at the same time overthrow the opposition. The selection and rejection of evidence must be determined from this standpoint.

_6. That evidence should be selected which will appeal most strongly to those to whom the argument is to be addressed._

In presenting an argument the writer or speaker must not always rely upon his own judgment as the criterion of the value of evidence. He must take the standpoint of those who are to hear or read. This attitude presupposes that the evidence offered is reliable. If a speaker or writer knows that evidence presented is unreliable but will nevertheless be accepted by his auditors or readers, he is perpetrating a fraud if he offers it. That reliable evidence which is most likely to appeal to those before whom it is to be placed should be selected. The arguer should put himself in the position of the persons to be persuaded, and ask himself the question, “What evidence would most strongly appeal to me and induce me to believe and act in the manner desired if I were the person to be persuaded?” The accuracy with which the advocate can perform this feat often measures his success. It requires the highest order of constructive imagination. He must view his position with all the prejudices and preconceived ideas, as well as the personal interests, of the persons to be persuaded. He must, for the time being, lose his character as an advocate and assume that of the reader or hearer.

In quoting opinions of authority this attitude of mind becomes most important. If the argument is to be addressed to an individual, the opinion or action should be cited of some person in whom that individual reposes confidence. If you wish to persuade John Jones to follow a certain course of action, and you are aware that his most intimate friend and the one to whom he looks as a model of discretion and good judgment is Smith, you can do no better than to quote the opinion of Smith, if Smith has expressed himself as favoring your contentions or if he has followed the course of action which you desire Jones to follow.

In addressing an organization of workmen it is effective to quote the opinions of their high officials in whom they repose trust and confidence. Likewise in addressing the members of any trade, profession, business, religious faith, or political party, the opinions of persons high in their particular field of endeavor may always be quoted. Sources of authority with which the audience is likely to be in sympathy should be especially emphasized.

In selecting evidence with which to prove the truth or falsity of a proposition too much care cannot be exercised. The foregoing rules should be adhered to strictly. They should assert themselves automatically. It is not enough for the student to have these rules of argumentation so well in mind that he can recite them in class and give them when asked for in an examination; he should have them so well in mind that they become a part of the argumentative process. If these rules can be remembered only with difficulty they will not be used, because it would involve too much trouble to stop and apply each rule to every fact and opinion offered in evidence. After the rules are thoroughly mastered, a half-hour’s practice in their application will serve to fix the habit of judicious selection of evidence so well in mind that the process will become automatic.

These suggestions in regard to the rules for selecting evidence apply with equal aptness to all other rules in this book. The person who wishes to become a master of argumentation must be able to command the rules of the art.

SUMMARY OF RULES FOR SELECTING EVIDENCE

1. The evidence must come from the most reliable source to which it can 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.

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

4. The selection of evidence must be fair and reasonable.

5. The position and arguments of the opposition should be taken into consideration.

6. That evidence which will appeal most strongly to those to whom the argument is to be addressed should be selected.

IV. The amount of evidence required.

The investigator must not stop collecting evidence until he has amassed a sufficient amount to prove his proposition. Naturally the question is at once asked, “What is the amount of evidence required to prove a proposition?” To answer this question in a satisfactory manner some careful thought is required. Since we are regarding argumentation as a practical art, and since when we consider it in this way we must conclude that its end is action, we are forced to admit that the amount of evidence is not sufficient unless it actually produces the result aimed at,—namely, the action of the person or persons addressed in a manner which conforms to the wishes of the arguer. It is therefore plain that the amount of evidence required varies with individual cases. The arguer must consider the importance of the question to those to whom the argument is addressed, as well as their prejudices and personal interests. He must consider these things in their relation to the present situation and then determine the amount of evidence in accordance with what his judgment tells him is required. If the argument is to be passed upon by judges whose duty it is to reach a conclusion but who are not personally interested in the result, the following rule may be applied: _Sufficient evidence must be produced to satisfy an unprejudiced mind beyond a reasonable doubt_.

In relying upon the above rule we must eliminate prejudice, personal interest, and results terminating in active or prolonged action. Therefore if prejudice or personal interest exists in any particular case, the first duty is to remove this prejudice or nullify the personal interest. If active or prolonged action is desired evidence sufficient in amount to induce this action must be produced. With these two limitations the rule stated above may be accepted as the measure of the amount of evidence required. There are, of course, some facts which may be presented without relying upon any special evidence or authority for their truth. All facts which are matters of common knowledge come within this class. Geographical facts, such as the fact that Boston, New York, and Savannah are seaports; historical facts, such as the fact that Alaska was purchased from Russia; political facts, such as the fact that the Southern States are largely adherents of the Democratic Party; and things which must have happened in the ordinary course of nature, such as the presumed death of a person born two hundred years ago, all may be stated without evidence to support them.

In determining the amount of evidence to be offered it is sometimes necessary to consider the different sources from which it is derived. Care should be taken not to place too great reliance upon one source. For example, in a debate on the prohibition question one speaker quoted statistics from a bulletin issued by the Anti-Saloon League, he relied for proof of his facts upon a committee report of the Anti-Saloon League, he offered the opinion of the President of the Anti-Saloon League, and finally quoted from the argument of a lawyer who is employed by the Anti-Saloon League. Aside from the charge of prejudice which might be made against this evidence, it is readily seen that too much reliance is placed in one authority. It might well be termed “an Anti-Saloon League argument.” No person is willing to accept some other person’s opinion or evidence in preference to his own, but if a number of authorities have arrived at substantially the same conclusion, or can offer evidence which points to the same conclusion, and there has been no collusion between them, any reasonable person will give such conclusions his most serious consideration. Furthermore, if the speaker or writer indicates that his evidence comes from various sources, it inspires confidence in his words, since the variety of the evidence offered indicates that the investigation has been broad and thorough.

The process of collecting evidence set forth in this chapter may be used in other fields besides that of argumentation. Every individual has frequent occasion to collect evidence regarding certain subjects connected with his business or occupation. Whatever the occasion for investigation the method of collecting evidence herein presented can be used to great advantage.

The student of argumentation is cautioned to follow explicitly the directions contained in this chapter. All the available sources of evidence should be consulted. The rules regarding the recording of evidence should be adhered to strictly. The recorded evidence should be carefully studied, with the view of determining its relative importance, according to the rules laid down for the selection of evidence. The student should feel satisfied in his own mind that he has secured an amount of evidence sufficient to establish each main issue. Then after these tasks are completed he can turn his attention to the next great step in argumentation,—the Construction of the Brief.

EXERCISES IN COLLECTING EVIDENCE

1. Make out a list of topics under which you would look for material on the following propositions:

a. The United States should impose a tariff for revenue only.

b. The United States should provide for an immediate increase in the navy.

c. Intercollegiate football should be abolished.