Our belief may be based upon the absence of facts proving the contrary as well as upon the presence of facts proving the proposition. If A has never told an untruth, that fact is an argument in favor of his truthfulness on the present occasion. A man who has never been dishonest may point to this as an argument in favor of placing him in a position of trust. Often the strongest evidence that we can offer in favor of a proposition is the absence of any fact that would support the negative conclusion.
The point of the whole matter is that from the observation of a large number of cases, we may establish the probable truth of a proposition, but emphasis needs to be laid upon the probability. We cannot be sure. Not all crows are black, though you may never have seen a white one. The sun may not rise to-morrow, though it has never failed up to this time. Still it is by this observation of many individual cases that the truth of the propositions that men do believe has been established. We realize that our inductions are often imperfect, but the general truths so established will be found to underlie every process of reasoning, and will be either directly or indirectly the basis upon which we build up all argument.
We may then redefine inductive reasoning as the process by which from many individual cases we establish the probable truth of a general proposition.
EXERCISES
Notice in the following selections that the truth of the conclusion is shown by giving particular examples:—
1. It is curious enough that we always remember people by their worst points, and still more curious that we always suppose that we ourselves are remembered by our best. I once knew a hunchback who had a well-shaped hand, and was continually showing it. He never believed that anybody noticed his hump, but lived and died in the conviction that the whole town spoke of him no otherwise than as the man with the beautiful hand, whereas, in fact, they only looked at his hump, and never so much as noticed whether he had a hand at all. This young lady, so pretty and so clever, is simply the girl who had that awkward history with So-and-so; that man, who has some of the very greatest qualities, is nothing more than the one who behaved so badly on such an occasion. It is a terrible thing to think that we are all always at watch one upon the other, to catch the false step in order that we may have the grateful satisfaction of holding our neighbor for one who cannot walk straight. No regard is paid to the better qualities and acts, however numerous; all the attention is fixed upon the worst, however slight. If St. Peter were alive he would be known as the man who denied his Master; St. Paul would be the man who stoned Stephen; and St. Thomas would never be mentioned in any decent society without allusions to that unfortunate request for further evidence. Probably this may be the reason why we all have so much greater a contempt for and distrust of each other than would be warranted by a correct balance between the good and the evil that are in each.
—Thomas Gibson Bowles: Flotsam and Jetsam.
2. In the first place, 227 withered leaves of various kinds, mostly of English plants, were pulled out of worm burrows in several places. Of these, 181 had been drawn into the burrows by or near their tips, so that the footstalk projected nearly upright from the mouth of the burrow; 20 had been drawn in by their bases, and in this case the tips projected from the burrows; and 26 had been seized near the middle, so that these had been drawn in transversely and were much crumpled. Therefore 80 per cent (always using the nearest whole number) had been drawn in by the tip, 9 per cent by the base or footstalk, and 11 per cent transversely or by the middle. This alone is almost sufficient to show that chance does not determine the manner in which leaves are dragged into the burrows.
—Darwin: Vegetable Mold and Earthworms.
3. The catastrophe of every play is caused always by the folly or fault of a man; the redemption, if there be any, is by the wisdom and virtue of a woman, and, failing that, there is none. The catastrophe of King Lear is owing to his own want of judgment, his impatient vanity, his misunderstanding of his children; the virtue of his one true daughter would have saved him from all the injuries of the others, unless he had cast her away from him; as it is, she all but saves him. Of Othello, I need not trace the tale; nor the one weakness of his so mighty love; nor the inferiority of his perceptive intellect to that even of the second woman character in the play, the Emilia who dies in wild testimony against his error:—