THE SCIENTIFIC METHOD IN THEOLOGY.

BY FRANK SARGENT HOFFMAN, PROFESSOR OF PHILOSOPHY IN UNION COLLEGE.

THE recent correspondence between Professor St. George Mivart and Cardinal Vaughan concerning the Professor's recent articles on the relation of educated Roman Catholics to the Bible, marks a most significant epoch in the history of religious thought. It brings most strikingly to view the fact that the time is past when any one can serve the cause of true religion by ignoring the methods of modern science. It also makes clear and vivid the necessity of establishing our theological beliefs on just the same scientific basis as our beliefs in any other sphere of inquiry, if they are going to influence in any effective way the thought of the future.

The aim of the present paper is to set forth with clearness the principles that underlie all our beliefs, and then to show how these principles are to be applied to the particular field of investigation we now have in view.

It is customary in discussing the method of science to go back to Aristotle and treat of the subject under the two distinct heads of induction and deduction. But we now see that the two methods are not wholly independent of each other. In reality, they are frequently blended or employed alternately in the pursuit of science. It is no exaggeration to say that all the more important and extensive investigations of science rely as much upon the one as upon the other. In both, the syllogism, with its major and minor premises and conclusion, holds the foremost place. For the syllogism is not only the form of deductive reasoning, but it is the true type of all reasoning properly so called. It may not be always necessary to express an argument in the form of a syllogism, but it must always be thrown into this form when scientific accuracy is required.

While there is little or no disagreement among thinkers about the nature and place of deduction in science, there is often a great deal of controversy over the sphere and proper function of induction. This arises from the fact that the term induction may be employed in at least three different senses.

In the first place, induction may be used to designate the old Socratic method of attaining definitions. This consists simply in enumerating all the particulars of a class. It is what is sometimes called a perfect induction; and, although it is in the form of reasoning, it is not reasoning at all. All we do in such a case is to solve a simple problem in addition and state the result.

Induction, according to the second meaning given to the term, is any process of adding to our knowledge. It was Bacon's chief objection to the Aristotelian logic that its premises were all taken for granted. It could never, in his opinion, in any way increase our knowledge. He therefore asked the question, How do we obtain our knowledge, and how do we progress in it? His answer to the question was, By induction; and, as contrasted with the old method, the term took on the meaning of any process that adds anything to what we already know at any given time. But this view of induction is too broad, just as the first view is too narrow. It includes every other mode of acquiring knowledge as well as reasoning, while the first view excludes reasoning altogether.

The third and most rational definition of induction represents it as the process of thought by which we pass from particulars to generals, or from effects to their causes. It is only in this sense that it can in any way be brought into contrast with deduction, as one of the essential methods employed in the pursuit of science.

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Of course, the chief preliminary step in any induction is the acquisition of the particulars, and this can only be done by the two processes of observation and experiment. But they do not form any part of induction properly so called. tainment of facts does not make a scientist. There are a thousand workers in science to one scientist. The most exact observers and the most skilful experimenters are not, by any means, the best scientists. Quite the opposite is probably the rule. Many of the world's greatest scientists have been notoriously defective in this respect. Nevertheless, a highly developed science, in any department of knowledge, is possible only upon the basis of a large supply of carefully ascertained facts.

The great and distinctive element in all induction is the formation of the hypothesis; and there can be no inductive science formed of any sort where this is not the chief feature.

What, then, is to be understood by an hypothesis, and what is the process the mind goes through in bringing it to view? An hypothesis is a supposition, a guess, or conjecture as to what the general fact is which includes the given particular facts, or what the cause is which has brought about the given effects. The term is sometimes contrasted with the term "theory," as though the two were necessarily distinct; an hypothesis being regarded as a mere possibility, while a theory is called a verified hypothesis. But this view is largely an arbitrary one, as the terms are often used interchangeably, as when we speak indifferently of the Darwinian hypothesis or the Darwinian theory.

Much might be said about the conditions most favorable for making a good hypothesis, but the chief thing that concerns us for our present purpose is the fact that every hypothesis, however formed, is always a product of the constructive imagination. All previous acts are simply by way of gathering material for the imagination to rearrange and recombine into a new creation.

In a certain sense, the mind takes a leap into the dark. It literally passes, per saltum, from the realm of the known to the realm of the unknown. From all the material that the memory places at its disposal it makes a guess or conjecture as to what will best meet all the exigencies of the situation.

It is for this reason that men of science, in all realms and in all ages, have always been men of powerful imaginations. The Greeks were the first great scientists of the race, because they were far more highly endowed than any other people with great imaginative powers. What they saw excited these powers and urged them to conjecture, to reason about things, and try to explain their nature and cause. It was well said by Dr. Carpenter that "it cannot be questioned, by any one who carefully considers the subject under the light of adequate knowledge, that the creative imagination is exercised in at least as high a degree in science as it is in art or poetry. Even in the strictest of sciences-mathematics— it can easily be shown that no really great advance, such as the invention of fluxions by Newton and of the differential calculus by Leibnitz, can be made without the exercise of the imagination." Given the hypothesis, the next step in the scientific process

is to verify it; and this is done by making the hypothesis the major premise of a deductive syllogism and noting the results. If the conclusions obtained coincide with the observed facts with which we started, the hypothesis is probably a correct one, and, others things being equal, may be accepted as an established truth. From this outline of the scientific method we see that no induction can be established beyond a high degree of probability. That is, no one can ever be absolutely certain that the hypothesis he assumes is a veritable truth. All generalizations in every science thus have their logical basis in the theory of probabilities.

When Bishop Butler asserted that "probability is the very guide of life," he might have added, “and we have no other." For all our judgments of what the past has been, or the present is, or the future will be, are necessarily formed on that basis; and as we are finite creatures and can never have infinite knowledge on any of these subjects, the knowledge we do have can never be more than probable.

The truth is that every man is so constituted by nature that he can never be absolutely certain of anything outside of the facts of his own consciousness and the simple intuitions necessarily involved therein; and when he makes an assertion transcending this realm, he passes at once into the sphere of the probable.

What we know with absolute certainty is never a matter of inference. It is never the result of a process of reasoning. It is always known directly, at once, by an immediate beholding. It is easy to see, therefore, that the realm of absolute certainty is a clearly limited one, and that the realm of probability includes within itself the great body of our knowledge. I am absolutely certain that I experience sensations, that I who experience them exist, and that the sensations have a cause; but I can be only probably certain that this particular concrete object was the cause. It is exceedingly easy for the most cautious person living to be mistaken in his judgments, and to draw wrong inferences from the data furnished by any one or all of his senses; and he can never be absolutely certain that he draws the right one. All the wisest man in the world can do is carefully to estimate the probabilities in the case and act accordingly. To say of a thing, "I have seen it with my own eyes," is only to make its existence probable; and to obey the injunction, "Handle me and see," can give only probable knowledge.

In every discussion of this sort a clear distinction should always be made between intuitively knowing and believing. I intuitively know a thing to be true when I am absolutely certain of it; I believe a thing to be true when I fall short, however little, of such certainty. That is to say, belief is simply imperfect knowledge. It is any kind of knowledge, in any sphere, which fails, in any respect, of being absolute. No proposition, perhaps, is more familiar to a beginner in logic than the statement, "All men are mortal," but even that assertion can be to him nothing more than a matter of a high degree of probability. For he has known only a very few men in the past, and as to those who may come to exist in the future he cannot positively assert that they will possess that property. He simply believes the proposition to be true, in just the same way, and no other, as he might believe in a material heaven, or a mountain of gold, or the real existence of a centaur.

Every natural scientist, I suppose, accepts and teaches the doctrine that every particle of matter attracts every other particle directly as the mass and inversely as the square of the distance. But he has examined only a few of the particles; and, from the very nature of the case, he can never be certain that those he has not examined are exactly like those he has. The doctrine furnishes him with a good working hypothesis. The probabilities are very high in its favor. But all he has any right to say about it is that he believes in the law of gravitation, not that he is absolutely certain of its truthfulness.

And so it is when we come to the realm of theology. We employ the same finite powers of mind in constructing a theology as in forming a science of botany or of physics. There is no difference in the kind of knowledge we have of each, but only in the class of objects taken into consideration. And my faith in the truth or falsity of their respective doctrines, and the degree of my faith in them, should always vary with the degree of their probability.

Theology, properly understood, is the science which seeks to account for the universe from the standpoint of God. It attempts to put all the known facts together into a system around this idea. It does not draw its material from any alleged revelation alone, although the revelation, if true, will furnish some of its most important data. But it gathers its material from every realm of knowledge. Every new fact discovered in any quarter