If we are told that a man who was in the Iroquois Theater fire was seriously burned, it seems reasonable to us because our experience recognizes burning as the result of such a situation.  But if we are told that a man who fell into the water emerged dry, or that a general who served under Washington was born in 1830, we discredit it because such statements are not in accord with our experience.  We are ready, then, to answer our question:  "What reasons will those in the audience believe?” They will believe those statements which harmonize with their own experience, and will discredit those which are at variance with their experience. This experience, as we have seen, may be first hand, or direct; or it may be indirect, or second hand.

In every case, the speaker’s argument must base every issue upon reasons that rest on what the hearers believe because of their own direct or indirect experience.  Suppose I assert:  “John Quinn was a dangerous man.”  Someone says:  “Prove that statement.”  I answer:  “He was a thief.”  Someone says:  “If that is true, he was a bad man, but can you prove him a thief?” Then I produce a copy of a court record which states that, on a certain day, a duly constituted court found John Quinn guilty of robbing a bank.  All my hearers now admit, not only that he was a thief, but also that he was a dangerous person.  I have given them a reason for my statement, and a reason for that reason, until at last I have shown them that my assertion, that John Quinn is a dangerous citizen, rests on what they themselves believe—­that a court record is reliable.

Sometimes an issue cannot be supported by a reason that will come at once within the experience of the audience.  It is then necessary to support the first by a second reason that does come within its experience.  Remember, then, as the fundamental rule, that the judges and audience will believe the issues of the proposition, and, as a result, the proposition itself, only when we show them, by the standard of their own experience, that we are right.

The reasons that we give in support of the issues are, in debating, called evidence.  Evidence is not proof; evidence is the material out of which proof is made.  Evidence is like the separate stones of a solid wall:  no one alone makes the wall; each one helps make it strong.  Evidence is like the small rods and braces of the truss bridge:  no one alone supports the weight; each helps to sustain the great beams that are the real support of the bridge.

Suppose we had the proposition:  “The Honor System of Examinations Should Be Established in the Greenburg High School.”  We assert:  “There is but one issue:  Will the students be honest in the examination?” Now, what evidence shall we use to show that they will be honest?  We may turn to the experience of other schools.  After a careful investigation we find evidence with which we may support the assertion in the following way: