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Argumentation is the process by which one mind presents to another the connection between some concrete individual fact and the general principle which determines that fact.
We have already seen that a general idea or force or principle produces individual objects, and that exposition presents the unity of individuals in the general. Argumentation seeks to establish the unity which exposition assumes. To expound ocean currents is to exhibit a connection between the individual currents and a common nature or principle which generates them, when such connection is supposed to be established and unquestioned. But to argue touching the same subject-matter is to strive to establish such connection. In all argumentation a relation of unity is under question. Hence, while in exposition the starting-point is a concept, in argumentation the starting-point is a judgment.
A judgment is the decision of the mind in regard to the unity between some particular object and a general truth. The relation of a general idea to some concrete reality, affirmed or denied as actual, is the world's battle ground of thought and arms. To say “ia beautiful landscape” or “developing man " presents a general conception which challenges neither denial nor support. But if it be said, The landscape is beautiful or Man has developed from a monkey, we have at once entered the arena. The moment we establish a relation and make an assertion, we become personally responsible. The tree, the planets, government, commerce, are not ours ; we may only think them. But the relations we establish are our relations; we ourselves give the sanction of our thought and identify our lives with the relation established. For this reason argumentation enters so largely into the affairs of men. In social, industrial, or political life, man regulates his conduct by the relation of truth to things, and this relation each establishes and asserts for himself, and thus brings himself into harmony or conflict with others, accordingly as his assertions agree or disagree with those of his fellowmen.
The most obvious relation involved in argumentation is the same as that in the other processes, namely, —
THE RELATION OF WHOLE AND PART.
Argumentation strives for the unity of the individual and the general, and thus unites the part in the whole. In arguing the mind moves from the whole to the part or from the part to the whole, accordingly as the one or the other is the known term of relation. One may know the general laws of planetary motion, and from this may reason to some new fact concerning an individual planet; or knowing some fact about one or more of the planets may reason to some new truth about planets taken as a whole. Either from a knowl
edge of the whole class a knowledge of a part is gained, or from a knowledge of a part of a class a knowledge of the whole is gained. Thus on the basis of direction of movement arguments are divided into two classes, deduction and induction.
Deduction. — As the word indicates, deduction is the downward way of knowing, as induction is the upward way. Deductive argument descends from general principles to particular facts. Some known truth of the whole class is carried down to increase a knowledge of the individuals of the class. The known term is the whole, and a knowledge of the part is sought. This process brings the part into further unity with the whole — makes a more complete identification.
The truth of the whole is united with the part through an intermediate whole, — a whole which includes the part and which is included in the larger whole. All reasoning is the unification of two ideas through a third. To judge is to connect two ideas directly; to reason is to connect two ideas indirectly through a third. An act of judgment is expressed by a proposition; but an act of reasoning is expressed by a syllogism which means a “reckoning all together.” The deductive syllogism stands thus:
All apples grow on trees;
This syllogism connects this apple with things growing on trees, through the intermediate whole, apples. Apples contain the attribute, growing on trees, and also contain this apple. Since growing on trees and this apple are both found in all apples, then growing on trees must be found in this apple or this apple must be found among things growing on trees. This suggests the
Law of Deductive Inference. — Conviction is carried by deduction through the axiom that whatever is common to the individuals of the whole class must be found in each part of the class. It is impossible to believe that all horses have four feet and at the same time believe that there is a horse which has not four feet. The law is that if the whole and the part are united in an intermediate term, one may be affirmed of the other; if not so united, the affirmation cannot be made. If one term is included and the other excluded from the intermediate term, then one may be affirmed not to be the other. If both are excluded from the intermediate term, no affirmation can be made.
Thus reasoning by deduction is largely a matter of imaging the terms in relation to the term through which they are to be united. For instance, using the syllogism before given, image all things growing on trees ; now image all apples, and this image will be found to fall within the first one. Next image this apple; it will fall in the second group. Now, since this apple appears in the second group and the second group falls within the first, there can be no mistake as to this apple's falling within the first; and this apple can confidently be said to belong among things growing upon trees. But suppose this syllogism be tested; —
All apples grow on trees;
Therefore, this fruit is an apple. As before, picture all things growing on trees, and within these things picture all apples. Now picture also this fruit among things growing on trees. While both apples and this fruit are among things growing on trees, this fruit need not be pictured as among apples. It may fall outside of apples and yet be inside of those things which grow upon trees, as cherries, peaches, etc. It cannot be affirmed, therefore, that this fruit is or is not an apple, and the syllogism proves to be false. Thus fallacies are readily detected by noting whether the major and the minor terms are united in a middle term.
A shortened form of the syllogism is used, called enthymeme, meaning to keep in mind, one of the judgments not being expressed. Thus, this apple grew on a tree because all apples grow on trees. The enthymeme is commonly used, it being expanded into a syllogism only for the purpose of testing the argument.
Induction. — While deduction moves from whole to part, or from principle to fact, induction moves from part to whole, or from fact to principle. Some apples are observed growing on trees, and it is inferred that all apples grow on trees. No one has observed all apples growing on trees, yet that they do so grow is a firm
tively a very few cases of apples growing on trees. One may believe that all crows are black from having