terms of those, or those in terms of these a question scarcely worth deciding, since either answer leaves us as completely outside of the reality as we were at first.

'Nevertheless, it may be as well to say here, once for all, that were we compelled to choose between the alternative of translating mental phenomena into physical phenomena, or of translating physical phenomena into mental phenomena, the latter alternative would seem the more acceptable of the two. Mind, as known to the possessor of it, is a circumscribed aggregate of activities; and the cohesion of these activities one with another, throughout the aggregate, compels the postulation of a something of which they are the activities. But the same experiences which make him aware of this coherent aggregate of mental faculties, simultaneously make him aware of activities that are not included in it-outlying activities which become known by their effects on this aggregate, but which are experimentally proved to be not coherent with it, and to be coherent with one another. As, by the definition of them, these external activities cannot be brought within the aggregate of activities distinguished as those of mind, they must for ever remain to him nothing more than the unknown correlatives of their effects on this aggregate, and can be thought of only in terms furnished by this aggregate. Hence, if he regards his conceptions of these activities lying beyond mind, as constituting knowledge of them, he is deluding himself; he is but representing these activities in terms of mind, and can never do otherwise. Eventually, he is obliged to admit that his ideas of matter and motion, merely symbolic of unknowable realities, are complex states of consciousness built out of units of feeling. But if, after admitting this, he persists in asking whether units of feeling are of the same nature as the units of force distinguished as external, or whether the units of force distinguished as external are of the same nature as units of feeling; then the reply, still substantially the same, is, that we may go further towards conceiving units of external force to be identical with units of feeling, than we can towards conceiving units of feeling to be identical with units of external force. Clearly, if units of external force are regarded as absolutely unknown and unknowable, then. to translate units of force into them is to translate the known

into the unknown, which is absurd. And if they are what they are supposed to be by those who identify them with their symbols, then the difficulty of translating units of feeling into them is insurmountable; if force, as it objectively exists, is absolutely alien in nature from that which exists subjectively as feeling, then the transformation of force into feeling is unthinkable. Either way, therefore, it is impossible to interpret inner existence in terms of outer existence. But if, on the other hand, units of force, as they exist objectively, are essentially the same in nature with those manifested subjectively as units of feeling, then a conceivable hypothesis remains open. Every element of that aggregate of activities constituting a consciousness, is known as belonging to consciousness only by its cohesion with the rest. Beyond the limits of this coherent aggregate of activities exist activities quite independent of it, and which cannot be brought into it. We may imagine, then, that by their exclusion from the circumscribed activities constituting consciousness, these outer activities, though of the same intrinsic nature, become antithetically opposed in aspect. Being disconnected from consciousness, or cut off by its limits, they are thereby rendered foreign to it. Not being incorporated with its activities, or linked with these as they are with one another, consciousness cannot, as it were, run through them; and so they come to be figured as unconscious— are symbolized as having the nature called material, as opposed to that called spiritual. While, however, it thus seems an imaginable possibility that units of external force may be identical in nature with units of the force known as feeling, yet we cannot, by so representing them, get any nearer to a comprehension of external force. For, as already shown, supposing all forms of mind to be composed of homogenous units of feeling variously aggregated, the resolution of them into such units leaves us as unable as before to think of the substance of mind as it exists in such units;, and thus, even could we really figure to ourselves all units of external force as being essentially like units of the force known as feeling, and as so constituting a universal sentiency, we should be as far as ever from forming a conception of that which is universally sentient.

'Hence, though of the two it seems easier to translate so-called

matter into so-called spirit, than to translate so-called spirit into so-called matter (which latter is, indeed, wholly impossible), yet no translation can carry us beyond our symbols. Such vague conceptions as loom before us are illusions conjured up by the wrong connotations of our words. The expression 'substance of mind,' if we use it in any other way than as the x of our equation, inevitably betrays us into errors; for we cannot think of substance save in terms that imply material properties. Our only course is constantly to recognize our symbols as symbols only, and to rest content with that duality of them which our constitution necessitates. The unknowable, as manifested to us within the limits of consciousness in the shape of feeling, being no less inscrutable than the unknowable as manifested beyond the limits of consciousness in other shapes, we approach no nearer to understanding the last by rendering it into the first. The conditioned form under which being is presented in the subject cannot, any more than the conditioned form under which being is presented in the object, be the unconditioned being common to the two.'1

V.

In the preceding paragraph we said that on the question of the relations between the physical and the moral some authors, taking the metaphysical point of view, think that the problem can be resolved, while others, basing themselves on experience, hold it to be insoluble. Further, we have seen that metaphysics fails to solve it: mechanism fails, because it reduces all to motion, which ultimately is not cognized, save on the condition of thought; and idealism fails, because it reduces all to thought, which does not exist without an object; so that neither of these two antithetic terms can absorb the other. The conclusion, therefore, must be that the problem is by its very nature insoluble. This, however, is not a return to a proposition long accepted, and in a manner classical. We will explain why it is not.

The commonly accepted dualism takes the metaphysical point of view; it opposes a substance which it does not know—mind—

1 Principles of Psychology, 2nd Edition, § 63.

to another substance it does not know-matter-without being able to reconcile them, as is natural, for how can light be produced out of the clash of two ignorances? On the contrary, the partisan of experience pronounces the question unsolvable, precisely because it transcends experience, that is to say, demonstrated or verifiable science. The one is pent within the impotency of his metaphysics; the other within the limits of his method. The ignorance of the former is owing to the gaps in his philosophy; that of the latter, to his voluntary abstention from all transcendental research.

In our times, the fine generalization known as the law of equivalence, or of the correlation of forces, has led some bold thinkers to state in another form the problem of the relations between the physical and the moral. Modern physics considers all the forces of nature-heat, light, electricity, magnetism, cohesion, chemical affinity, gravity—as capable of being reduced all to one principle, and of being transformed into one another in accordance with fixed rules, which are nothing else but the laws of mechanics. It is also generally admitted that the law of equivalence governs vital phenomena, and muscular contraction and innervation in particular. But is it also applicable to mental phenomena ? Is it possible for it to pass from nerve facts to states of consciousness? Do mental forces enter the category of the other forces, and are they in like manner convertible ?

Some authors in our day answer affirmatively. Bain has accumulated and cited some facts from which he infers, (1) the equiva valence or transmutability of nervous and mental forces, and (2) the equivalence or transformation of the mental forces into one another. Thus, according to him, it would be possible to establish an equivalence on the one hand between a certain nervous state and a certain mental state, and on the other hand between the three principal forms of mental life-sensibility, will and intelligence; so that a state of consciousness would imply the transformation and expenditure of a certain amount of nerve-force; and an increase of sensibility would be possible only by a diminution of intelligence and will, the sum of force in the living being remaining constant amid all these transformations. The magnificent synthesis contained in Herbert Spencer's First Principles reduces all phenomena without exception to the law of equivalence.

'No thought, no feeling,' says the author, 'is ever manifested, save as the result of a physical force. This principle will before long be a scientific common place.'

They who hold this doctrine observe that nervous force, which ultimately results from nutrition, must, after it is produced, be expended in one or other of these three ways: either by acting on the viscera, the heart, or the digestive organs, as is the case in deep emotion; or by acting on the muscles and producing movements, gestures, and various expressions of the physiognomy; or by causing the excitation to pass to some other part of the nervous system, and hence result those successive states which make up consciousness. Sensations excite ideas and emotions; the latter in turn awaken other ideas and emotions, and so on-that is to say, the tension existing in certain nerves, or groups of nerves, when they give us sensations, ideas, or emotions, produces an equivalent tension in some other nerves, or groups of nerves, with which they are connected.

But the facts cited in support of this thesis do not appear to us to be all equally conclusive. Some of them are no doubt transformations, but then others are rather correspondences. Thus, the pain which is transformed into cries and extravagant contortions is of short duration; pain which endures is reticent of expression. And the same is to be said of anger. But in certain cases-for example, in the cerebral excitation produced by hasheesh or opium -it is not quite certain that between the nervous state and the mental state there exists equivalence, transformation, and not simply correspondence.

This doctrine of the correlation of physical forces and thought is as yet hardly more than an outline. It is still in the qualitative period, and it is doubtful whether it will very soon enter on the quantitative period, which alone can constitute it a science. It is however a promising field, and one well adapted to exercise free and daring minds. If it could be demonstrated scientifically, it is evident that then the problem of the relations between the physical and the moral would come before us in a new aspect: it would be only a particular case of the law of the correlation of forces. We need not say that such a solution, restricted to experience, would