The game of football benefits the players physically, because
(Induction.)
1. Football is known to have benefited Henry Harvey. 2. Football is known to have benefited Frank Barrs. 3. Football is known to have benefited Penn Armstrong.
(Deduction.)
1. The game affords the players regular exercise. 2. The game takes them out in the open air. 3. The game develops the lungs.
The deductive reasoning expressed in full would be:—
(1) A. All games that afford the players regular exercise benefit them
physically.
B. Football affords the players regular exercise.
C. Therefore football benefits the players physically.
The reasoning given in (2) and (3) may be expressed in similar syllogisms.
To test the inductive part of this argument, one should determine how well the three examples show the existence of a general law. To test the deductive part, he should ask whether the premises, both those stated and those suppressed, are admitted facts, or whether they need to be proved.
If all reasoning were purely inductive or purely deductive, and if it always appeared in as simple a form as in the preceding illustration, one would have little difficulty in classifying and testing it. But frequently the two kinds appear in such obscure form and in such varied combinations that only an expert logician can separate and classify them. Because of this difficulty, it is worth while to know a second method of classification, one which is often of greater practical service than the method already discussed in assisting the arguer to determine what methods of reasoning are strong and what are weak. A knowledge of this classification is also very helpful to one who is searching for ways in which to generate proof. This method considers proof from the standpoint of its use in practical argument; it teaches not so much the different ways in which the mind may work, as the ways in which it must work to arrive at a sound conclusion.