THE DISCUSSION—CONVICTION
It has been seen that one who wishes to establish the truth or the falsity of a proposition must answer certain vital questions that are bound to arise in connection with it. Then, as different persons may answer these questions in different ways, it becomes necessary for him to convince his audience that his answers are correct. He must always beware of assertiveness. This defect occurs whenever a speaker or writer makes a statement but does not establish its truth. As simple denial is always sufficient answer to mere assertion, an unsupported statement is worthless. No one can hope to win in debate or change another's belief unless he can prove that what he says is true; he must substantiate with proof every statement that he makes, and show that no possibility for error or deceit can exist. In argumentation every statement not commonly accented as true must be proved.
The following passage is a highly assertive bit of argument; its worthlessness is apparent.
The decision of Congress to increase still further our already enormous navy is an injustice to every individual who contributes to the support of the national government. It is a crime to squander millions of money on a fleet that we do not need. Our navy to-day is more than the equal of any foreign armament that floats. Though second in number of ships, it ranks first in efficiency among all the navies of the world. No other country can boast of such marksmanship as our gunners display; no other country can boast of such armor plate as is to be found on our first-class battleships; not even England can successfully compete with us in seamanship and in general efficiency.
Proof is "anything which serves either immediately or mediately to convince the mind of the truth or the falsehood of a fact or proposition." [Footnote: On Evidence, Best, p. 45.] Belief in a specific statement is induced by a presentation of pertinent facts, and usually by a process of reasoning whereby from the existence of these known facts, the conclusion, hitherto unaccepted, is reached. Those facts that have to do with the proposition under discussion are known as evidence. The process of combining facts and deriving an inference from them is known as reasoning. Evidence may be made up of the testimony of witnesses, the opinion of experts, knowledge derived from experience, the testimony of documents, or circumstances that are generally known to have existed. Reasoning is the process by which men form opinions, render judgments, explain events, or in any way seek new truths from established facts.
In the following bit of proof, notice the facts that are stated, and see how, by a process of reasoning, they go to substantiate the idea that they are intended to prove:—
New York hires two policemen where Nashville hires one, and pays them double the salary; yet Nashville is as peaceable and orderly as New York. In Nashville any child of school age can have a seat in the public schools all through the year; in New York there has been a shortage of seats for many years. Nashville has a filtered water supply; New York is going to have one as soon as the $12,000,000 filtration plant can be built at Jerome Park. Street car fares are five cents in both cities; in Nashville one can always get a seat; in New York one has to scramble for standing room. The southern city maintains hospitals, parks, food inspectors, and all other things common to New York and other large cities. Apparently, Nashville is giving as much to its inhabitants for six dollars per capita as New York for thirty-one. These facts can point to but one conclusion—that Nashville has a superior system of government.
Since the first step in the generation of proof is the discovery of facts, the arguer should at the very outset become sufficiently familiar with the various kinds of evidence to estimate the value and strength of each idea that has a bearing upon the subject.
I. EVIDENCE.
There are two kinds of evidence: (a) direct, and (b) indirect or circumstantial. If a man sees a gang of strikers set fire to the buildings of their former employer, his evidence is direct. If, however, he only sees them stealthily leaving the buildings just before the fire breaks out, his evidence is indirect. In the latter case the man's testimony is direct evidence that the men were in the vicinity of the fire when it started, but it is indirect evidence that they perpetrated the crime. If a student who has failed to do good work throughout the term, and who has had little or no opportunity for special preparation, passes in a perfect paper at the close of an examination, the presumption is that he has received aid. The evidence on which this supposition rests is entirely circumstantial. But if some one saw the student obtaining aid, that fact would be direct evidence against him.