three manifestations of mind—sensations, emotions and thoughts—are mutually exclusive in their tendencies. The patient forgets the fear of the result in the pain of the operation; in intense thought the pulse falls, the senses do not respond, emotions and action are absent. We may say that ideally the unimpeded exercise of the intellect forbids either sensation or emotion.
Contrasting sensation and emotion, on the one side, with intellect on the other, feeling with thought, they are seen to be polar or antithetical manifestations of mind. Each requires the other for its existence, yet in such wise that the one is developed at the expense of the other. The one waxes as the other wanes. This is seen to advantage when their most similar elements are compared. Thus consciousness in sensation is keenest when impressions are strongest; but this consciousness is a bar to intellectual self-consciousness, as was pointed out by Professor Ferrier in his general Law of consciousness.20–1 When emotion and sensation are at their minimum, one is most conscious of the solidarity of one’s thoughts; and just in proportion to the vividness of self-consciousness is thought lucid and strong. In an ideal intelligence, self-consciousness would be infinite, sensation infinitesimal.
Yet there is a parallelism between feeling and thought, as well as a contrast. As pain and pleasure indicate opposite tendencies in the forces which guide sensation and emotion, so do the true and the untrue direct thought, and bear the same relation to it. For as pain is the warning of death, so the untrue is the detrimental, the destructive. The man who reasons falsely, will act unwisely and run into danger thereby. To know the truth is to be ready for the worst. Who reasons correctly will live the longest. To love pleasure is not more in the grain of man than to desire truth. “I have known many,” says St. Augustine, “who like to deceive; to be deceived, none.” Pleasure, joy, truth, are the respective measures of life in sensation, emotion, intellect; one or the other of these every organism seeks with all its might, its choice depending on which of these divisions of mind is prominently its own. As the last mentioned is the climax, truth presents itself as in some way the perfect expression of life.
We have seen what pleasure is, but what is truth? The question of Pilate remains, not indeed unanswered, but answered vaguely and discrepantly.21–1 We may pass it by as one of speculative interest merely, and turn our attention to its practical paraphrase, what is true?
The rules of evidence as regards events are well known, and also the principles of reaching the laws of phenomena by inductive methods. Many say that the mind can go no further than this, that the truth thus reached, if not the highest, is at least the highest for man. It is at best relative, but it is real. The correctness of this statement may be tested by analyzing the processes by which we acquire knowledge.
Knowledge reaches the mind in two forms, for which there are in most languages, though not in modern English, two distinct expressions, connaitre and savoir, kennen and wissen. The former relates to knowledge through sensation, the latter through intellection; the former cannot be rendered in words, the latter can be; the former is reached through immediate perception, the latter through logical processes. For example: an odor is something we may certainly know and can identify, but we cannot possibly describe it in words; justice on the other hand may be clearly defined to our mind, but it is equally impossible to translate it into sensation. Nevertheless, it is generally agreed that the one of these processes is, so far as it goes, as conclusive as the other, and that they proceed on essentially the same principles.22–1 Religious philosophy has to do only with the second form of knowledge, that reached through notions or thoughts.
The enchainment or sequence of thoughts in the mind is at first an accidental one. They arise through the two general relations of nearness in time or similarity in sensation. Their succession is prescribed by these conditions, and without conscious effort cannot be changed. They are notions about phenomena only, and hence are infinitely more likely to be wrong than right. Of the innumerable associations of thought possible, only one can yield the truth. The beneficial effects of this one were felt, and thus by experience man slowly came to distinguish the true as what is good for him, the untrue as what is injurious.
After he had done this for a while, he attempted to find out some plan in accordance with which he could so arrange his thoughts that they should always produce this desirable result. He was thus led to establish the rules for right reasoning, which are now familiarly known as Logic. This science was long looked upon as a completed one, and at the commencement of this century we find such a thinker as Coleridge expressing an opinion that further development in it was not to be expected. Since then it has, however, taken a fresh start, and by its growth has laid the foundation for a system of metaphysics which will be free from the vagaries and unrealities which have thrown general discredit on the name of philosophy.
In one direction, as applied logic and the logic of induction, the natural associations of ideas have been thoroughly studied, and the methods by which they can be controlled and reduced have been taught with eminent success. In this branch, Bentham, Mill, Bain, and others have been prominent workers.
Dealing mainly with the subjects and materials of reasoning, with thoughts rather than with thinking, these writers, with the tendency of specialists, have not appreciated the labors of another school of logicians, who have made the investigation of the process of thinking itself their especial province. This is abstract logic, or pure logic, sometimes called, inasmuch as it deals with forms only, “formal logic,” or because it deals with names and not things, “the logic of names.” It dates its rise as an independent science from the discovery of what is known as “the quantification of the predicate,” claimed by Sir William Hamilton. Of writers upon it may be mentioned Professor De Morgan, W. Stanley Jevons, and especially Professor George Boole of Belfast. The latter, one of the subtlest thinkers of this age, and eminent as a mathematician, succeeded in making an ultimate analysis of the laws of thinking, and in giving them a symbolic notation, by which not only the truth of a simple proposition but the relative degree of truth in complex propositions may be accurately estimated.24–1
This he did by showing that the laws of correct thinking can be expressed in algebraic notation, and, thus expressed, will be subject to all the mathematical laws of an algebra whose symbols bear the uniform value of unity or nought (1 or 0)—a limitation required by the fact that pure logic deals in notions of quality only, not of quantity.
This mathematical form of logic was foreseen by Kant when he declared that all mathematical reasoning derives its validity from the logical laws; but no one before Professor Boole had succeeded in reaching the notation which subordinated these two divisions of abstract thought to the same formal types. His labors have not yet borne fruit in proportion to their value, and they are, I believe, comparatively little known. But in the future they will be regarded as epochal in the science of mind. They make us to see the same law governing mind and matter, thought and extension.
Not the least important result thus achieved was in emphasizing the contrast between the natural laws of mental association, and the laws of thinking which are the foundation of the syllogism.
By attending to this distinction we are enabled to keep the form and the matter of thought well apart—a neglect to do which, or rather a studied attempt to ignore which, is the radical error of the logic devised by Hegel, as I shall show more fully a little later.
All applied logic, inductive as well as deductive, is based on formal logic, and this in turn on the “laws of thought,” or rather of thinking. These are strictly regulative or abstract, and differ altogether from the natural laws of thought, such as those of similarity, contiguity and harmony, as well as from the rules of applied logic, such as those of agreement and difference. The fundamental laws of thinking are three in number,
