no hesitation in ascribing the death to the gun-shot wound or the dose of poison. Nor is this confidence the effect of any wide experience, for if it were the first time that we had seen a gun fired, or a dose of poison administered, we should have no hesitation in ascribing the altered condition of the animal to this novel cause; we should know that there was only one new circumstance operating upon it, and consequently, that any change in its condition must be due to that one circumstance." 1

This analysis is wholly incorrect. When a man falls dead on the street we are at a loss for a cause. Many events, observable and unobservable, are occurring at the same time; the man may have had heart disease. We proceed to make an hypothesis according to the established rules. The first inquiry of the mind is for some already accepted primary induction under which to class the event. If a small boy should shoot off a Chinese fire-cracker, and at that moment some one should fall, we should not connect the two events, because we already have the induction that fire-crackers do not kill.

This impossibility of knowing always whether isolation is perfect, leads to the rule that in studying any phenomenon, we should vary the circumstances as much as possible, and use each of the applicable methods of proof independently. Yet even then we are liable to err, as the following example shows:

"Thales of Miletus, who lived in the sixth century B.C., and who was called 'the first of natural philosophers' by Tertullian, and 'the first who inquired after natural causes' by Lactantius, affirmed that water was the first principle of things, perhaps, according to some writers, because Homer had made Okeanos the source of the gods. At least we are reminded of the boundless

1 Inductive Logic, p. 151.

watery chaos of older cosmogonies. This doctrine of Thales was not without its supporters during the Middle Ages, and, indeed, the convertibility of water into earth and air was not absolutely disproved until about a century ago. One of the ablest supporters of the dogma was Van Helmont (b. 1577, d. 1644), who affirmed that all metals, and even rocks, may be resolved into water; animal substances are produced from it, because fish live upon it; and vegetable substances may also be produced from it. This assertion he endeavored to prove by what would appear to be a very conclusive experiment in those days, when neither the composition of the air nor of water was known. He took a willow which weighed five pounds, and planted it in two hundred pounds of earth, which he had previously carefully dried in an oven. The willow was frequently watered, and at the end of five years he pulled it up and found that its weight amounted to one hundred and sixty-nine pounds and three ounces. The earth was again dried and was found to have lost only two ounces. Thus it appeared that 164 pounds of wood, bark, roots, leaves, etc., had been produced from water alone. Hence he inferred that all vegetables are produced from water alone; not knowing, as was afterwards proved by Priestley, that a constituent of the atmosphere, called carbonic acid, had furnished the solid part of the tree, although, indeed, there was much water with it.”1

This experiment of Van Helmont was, so far as he could know, a rigorous application of the famous test of difference; yet it wholly failed to teach the truth, because the supposed isolation was unreal.

Under this head belongs the well-known fallacy Post hoc, ergo propter hoc. No one would have the hardihood to argue that since the group of antecedents ABCDEFGHIJK have been followed by the consequents Imnopqrstuv, therefore C must be the cause of q; but it is often convenient for a crank or a demagogue to fasten attention upon the fact that after C

1 Rodwell's Birth of Chemistry, p. 14.

followed 9, the unspoken assumption being that isolation is conceded, that C was the only new antecedent, and q the only new consequent. Thus, it is a familiar fact in politics that hard times, whatever may have been their causes, discredit the party in power, the outs arguing that since the present administration came into office money has been scarce, and wholly omitting to refer to speculation, drought, or any other cause of financial depression.

It is a mistake in isolation to overlook the Mutuality of Cause and Effect. This is illustrated in the following remarks of Sir G. C. Lewis:

"An additional source of error in determining political causation is likewise to be found in the mutuality of cause and effect. It happens sometimes that when a relation of causation is established between two facts it is hard to decide which, in the given case, is the cause and which the effect, because they act and react upon each other, each phenomenon being in turn cause and effect. Thus, habits of industry may produce wealth; while the acquisition of wealth may promote industry; again, habits of study may sharpen the understanding, and the increased acuteness of the understanding may afterward increase the appetite for study. So the excess of population may, by impoverishing the laboring classes, be the cause of their living in bad dwellings; and, again, bad dwellings, by deteriorating the moral habits of the poor, may stimulate population. The general intelligence and good sense of the people may promote its good government, and the goodness of the government may in its turn increase the intelligence of the people, and contribute to the formation of sound opinions among them. Drunkenness is in general the consequence of a low degree of intelligence, as may be observed both among savages and in civilized countries. But, in return, a habit of drunkenness prevents the cultivation of the intellect, and strengthens the cause out of which it grows. As Plato remarks, education improves nature, and nature facilitates education. National character, again, is

both effect and cause; it reacts on the circumstances from which it arises. The national peculiarities of a people, its race, physical structures, climate, territories, etc., form originally a certain character, which tends to create certain institutions, political and domestic, in harmony with that character. These institutions strengthen, perpetuate, and reproduce the character out of which they grew, and so on in succession, each new effect becoming, in its turn, a new cause. Thus a brave, energetic, restless nation, exposed to attack from neighbors, organizes military institutions : these institutions promote and maintain a warlike spirit; this warlike spirit, again, assists the development of the military organization, and it is further promoted by territorial conquests and success in war, which may be its result—each successive effect thus adding to the cause out of which it sprung.

1 On Methods of Observation and Reasoning in Politics, vol. i, p. 375, quoted by Fowler, Inductive Logic, p. 322.

CHAPTER XVI.

THE WORK OF BACON.

The last chapter contains

Two great names stand out conspicuous beyond all others in the development of Inductive Logic: they are those of Bacon and of Mill. Of the latter enough has already been said to give the reader a knowledge of the main points of his doctrine. a long quotation which well represents the style of the Novum Organum. But it seems undesirable to close this book without devoting a brief chapter to an estimate of the debt which we owe to that Prince of Philosophers," who, with the "Prince of Poets," according to Lord Macaulay, "made the Elizabethan age a more glorious and important era in the history of the human mind than the age of Pericles, of Augustus, or of Leo."

ee

Francis Bacon, Baron Verulam (1561–1626), is commonly regarded as the founder of modern inductive science. Reid expresses this opinion as follows:

"After man had labored in the search of truth near two thousand years by the help of Syllogisms, Lord Bacon proposed the method of INDUCTION as a more effectual engine for that purpose. His Novum Organum gave a new turn to the thoughts and labors of the inquisitive, more remarkable and more useful than that which the Organon of Aristotle had given before, and may be considered a second grand era in the progress of human nature.” 1

1 Hamilton's Reid, p. 712; quoted by Minto, Logic, p. 244.