The examples so far given have all shown a universe unduly curtailed or simplified through the neglect to consider some one or more of its essential relations

The

or members. But there are cases in which the neglected whole. very existence of a universe of interrelated members seems to be ignored. To quote Whately once more (though here again he gave the example under another head):

"When a multitude of particulars are presented to the mind, many are too weak or too indolent to take a comprehensive view of them; but confine their attention to each single point, by turns: and thus decide, infer, and act accordingly: e.g., the imprudent spendthrift, finding that he is able to afford this, or that, or the other expense, forgets that all of them together will ruin him.

"To the same head may be reduced that fallacious reasoning by which men vindicate themselves to their own conscience and to others, for the neglect of those undefined duties, which though indispensable, and therefore not left to our choice whether we will practise them or not, are left tổ our discretion as to the mode, and the particular occasions, of practising them; e.g., 'I am not bound to contribute to this charity in particular; nor to that; nor to the other': the practical conclusion which they draw is, that all charity may be dispensed with.”

In each of these cases the trouble lies, as Whately so clearly says, in the failure to "take a comprehensive view" of the universe as a whole. In the former case we forget that when a given variable (namely, the money at one's disposal) is placed there it cannot also be placed here; in the latter we forget that if the variable (namely, charity) is not placed there, it ought to be placed here, since it ought to have a place somewhere or other in the universe.

The same failure to keep the whole universe and its relathe system, no hard and fast line can be drawn between a case of the forgotten member and a case of the forgotten relation.

tions in view accounts for what Whately calls the Fallacy of Objections, i.e., "showing that there are objections against some plan, theory, or system, and thence inferring that it should be rejected; when that which ought to have been proved is, that there are more, or stronger, objections against the receiving than the rejecting of it. . . . For there never was, nor will be, any plan executed or proposed, against which strong and even unanswerable objections may not be urged; so that unless the opposite objections be set in the balance on the other side, we can never advance a step."

This Fallacy of Objections is peculiarly characteristic of people whose energy is small but whose moral or æsthetic sensibilities are morbidly developed. They should help to pay a detective to catch a thief, and refuse because a detective's work is not straightforward and frank; they should help to hang a murderer, or should shoot a murdering burglar to secure the safety of honest people, and hold back because it is cruel; they want the liquor traffic cut down and they are convinced that a license system is the only thing that will do it, but they object to this because it makes the government a partner in sin'; they should wash their clothes, but they are afraid of soiling their fingers. Perhaps there is some relation in life in which each of us strains for ever at gnats and swallows camels. We see the gap in the universe, but there is no ideal material at hand, so we let it go unfilled:

6

"Our common problem, yours, mine, every one's,

Is, not to fancy what were fair in life

Provided it could be, but finding first

What can be, then find how to make it fair

Up to our means; a very different thing."

CHAPTER XXI.

THE DIFFERENCE BETWEEN INDUCTION AND DEDUCTION.

This impression

THE student who has followed the preceding chapters at all thoughtfully has doubtless been impressed by a keen and disappointing sense of limitation: there are so many things that we must not do, and so few that we may, so Difference many cautions to hold us back, and so few posi- in limitations. tive principles to help us on. is well founded. The principles of deductive logic are important indeed and should never be forgotten: and yet if any one dwells on them exclusively, and forgets that cautions would be worthless in the absence of some positive forward impulse, he is likely to become a mere carping critic; a faultfinder, who is forever detecting flaws in the reasoning of others, but utterly incapable of doing any constructive work of his own.

Its

Induction is that part of logic which is concerned with the onward movement that deduction cannot undertake. essential task can be best understood by looking once more at the limitations of the syllogism and then seeing how it tries to supplement them. The first figure teaches that if every A is a B and every B is a C, it is safe to conclude that But it does not tell how to find out in the every A is a C. first place that every A is a B or that every B is a C. It proceeds in this case, as they say, from generals to particulars, but not from particulars to generals. Induction tells us how to prove in the first place that every A is a B or that

every B is a C; how to get from particulars to generals. The second figure teaches that dissimilarity proves objects not to be identical; but it does not help us to prove that objects are identical. Induction does. The third figure teaches that the coexistence of relations proves that they are compatible, that they may come together; but it does not try to prove that they are necessarily connected, so that they must come together. Induction does. Thus in the case of each figure induction attempts a task in the presence of which deduction is helpless. This work of getting more general or more positive or more emphatic results than those reached by the syllogism is not the whole of inductive logic any more than the syllogism itself is the whole of deductive; but, like the syllogism in deduction, it is the heart of the subject.*

Why Induction is able to go ahead and do more than Deduction we shall understand better when we have reached the close of the next chapter, and better still when we have gone farther. But there are three things about Induction by which we can explain at least a part of the difference now.

In the first place, every system of Induction rests on the assumption that facts of true logical significance can be attained by direct observation. If a person whose mental life was limited to deductive reasoning were asked whether the man in front of him had light hair or dark, he might be in possession of some premises that would enable him to answer the question or he might not; and if he had no such premises, he

*It is often said that the difference between Deduction and Induction is that the one proceeds from generals to particulars, while the other proceeds from particulars to generals; that is to say, that deduction proceeds from statements about classes of things to statements about smaller classes or about individuals, while induction proceeds from statements about individuals to statements about classes. But in deduction it is only the first figure of the syllogism that goes from statements about classes to statements about the individuals in them; and in induction it is only the process corresponding to the first figure that is concerned with mere generalization. This statement, therefore, is based upon too narrow a view of the scope of both branches of Logic,

could not answer it. But the one thing which he could not do would be to look at the man and see. Reasoning absolutely limited to deduction is eminently suited to people like the monastic scholars of the middle ages who did not profess to possess any other source of true knowledge than the written word of the Church as found in some recognized authority, such as the Bible or the works of Aristotle or St. Thomas. To the orthodox Scholastic every opinion at variance with such authorities was not only false but wicked. "There is a characteristic anecdote of Scheiner, who contests with Galileo the honor of being the first to observe the spots in the sun. Scheiner was a monk; and, on communicating to the superior of his order the account of the spots, he received in reply from that learned father a solemn admonition against such heretical notions: I have searched through Aristotle,' he said, 'and can find nothing of the kind mentioned; be assured, therefore, that it is a deception of your senses or of your glasses.'"* Thus, to the Scholastic, the data for reasoning were all given by some authority, and usually in the form of general propositions. In contrast with this, Induction supposes us to be set loose in the world with all our senses about us to collect our own data; to find the straw as well as to make the bricks.

Now all observation is of individual facts. General truths may be inferred; but the facts on which they are (or should be) based must be observed one at a time. Consequently, while the Deductive reasoner is accustomed to appeal for the most part to general principles of some sort by way of premises, and thus learns to regard such principles with a certain veneration, the Inductive reasoner is appealing all the time to individual facts as revealed by the senses, and he gives a large share of his veneration to them. Hence the saying that in science a single fact is worth a bushel of theory. In the second place, Induction distinctly recognizes the * Baden Powell's "History of Natural Philosophy", p. 171. Quoted in Fowler's "Inductive Logic ", p. 293.