cannot follow the author through this very long and delicate analysis, in which he traces the genesis. We must limit ourselves to a few words.

The result of the first integration, as we have seen, is to unite together a certain number of nervous shocks, and make a sensation of them. Each integration of this kind supplies what we call a simple sensation. But these sensations themselves may be mingled together, and produce by their integration a composite sensation. Now, similar sensations become integrate among themselves. Again, a sensation unites itself so as to form an aggregate with other sensations which limit it in time or space. Finally, the integrate clusters which result therefrom enter into the higher integrations of one kind and the other. Let us remark in support of the preceding, that in the domain of mind we hardly comprise these series of states of consciousness whose integration is imperfect, and that, on the contrary, the series whose integration is pushed the furthest possible are those which we consider as belonging especially to mind. For instance, hunger, thirst, sickness, all the visceral sensations in general, and even feelings like love and anger, which have but little cohesion between them, which form badly integrated clusters, are regarded as occupying only a subordinate place in what we call mental life. Mental acts, on the contrary, are those which belong to the order of tactile, auditive, visual sensations, which have much cohesion, and are remarkably integrate. Our intellectual operations are almost always restricted to the sensations of hearing (integrate in words) and to visual sensations (integrate in impressions, objects, and their relations).

The nature of mind being thus conceived, it will be elucidated by comparing it with the nature of matter, and this fact, that there exists a parallelism between that which chemists have established relatively to matter and that which we suppose here relatively to mind, will aid us to justify our conception.

It is established that a great number of substances which seem homogeneous and simple, are in reality heterogeneous and composite, and it is shown by analysis that many which seem entirely without relation to each other are in truth analogous. There is a large class of salts formed by sulphuric acid, another

large class formed by nitric acid, and another large class formed by acetic acid, and so on in succession. These classes of acids are different in many respects, but it has been discovered that the former have a characteristic common to them with many others, the possession of oxygen as an active element. Further, there is reason to suspect that the substantives called simple are themselves composite, and that there is finally only one ultimate form of matter, of which all the other forms are only compositions more and more complex.

So it is with regard to mind. We can conceive that these innumerable forms of spiritual life, which are given to us at different states of consciousness may be finally composed of simple units of feeling, and even of units which are at bottom of the same kind. But these homogeneous units produced by integrations of a different sort produce feelings relatively simple, then feelings more and more complex and different, and thus continually.

It must not, however, be supposed that all that has just been said about mind is in disagreement with the preceding assertion of the author. We know nothing about mind. When those two modes of existence which we call subject and object have been reduced, each to its ultimate expression, it only remains for us to endeavour to assimilate those two ultimate expressions to each other. But the distinction of subject and object in itself implies the impossibility of any assimilation, 'for this distinction. is the consciousness of a difference which surpasses all other differences.' On this important point we shall let the author himself speak :

'Here, indeed, we arrive at the barrier which needs to be perpetually pointed out, alike to those who seek materialistic explanations of mental phenomena and to those who are alarmed. lest such explanations may be found. The last class prove by their fear almost as much as the first prove by their hope, that they believe Mind may possibly be interpreted in terms of Matter; whereas many whom they vituperate as materialists are profoundly convinced that there is not the remotest possibility of so interpreting them. For those, who, not deterred by foregone conclusions, have pushed their analysis to the uttermost, see very

clearly that the conception that we form to ourselves of matter is but the symbol of some form of power absolutely and for ever unknown to us, and a symbol which we cannot suppose to be like the reality without involving ourselves in contradictions (First Principles, p. 16, etc.) They also see that the representation of all objective activities in terms of motion is but a representation of them and not a knowledge of them, and that we are immediately brought to alternative absurdities if we assume the power manifested to us as motion to be in itself that which we conceive as motion.' 21

When, to these conclusions, that matter and motion, such as we think them, are only the symbols of unknowable forms of existence, we join the recently drawn conclusion that mind is also unknowable, and that the most simple form under which we can think substance is only a symbol of something which can never come under thought, then we see that the whole question reduces itself to knowing whether these symbols may be expressed in terms as symbols of so-and-so, a question which is hardly worth decision, since either reply leaves us as entirely ignorant of the reality as we were before.

Nevertheless it may be well to say, once for all, that if we were constrained to choose between the alternative of translating mental into physical phenomena, or physical into mental, the latter would seem the more acceptable of the two. Mind, such as it is known to be by him who possesses it, is a circumscribed aggregate of activities, and the cohesion of these activities one with the other postulate a something of which they are the activities. But the same experiences which make him know this coherent aggregate of mental activities make him simultaneously know activities which are not included in the aggregate-activities placed outside, which are only known by their effects on this aggregate, but which, as experience proves, have no cohesion with the aggregate, though they have cohesion between themselves (First Principles, pp. 43, 44). As, by their definition, these external activities cannot be comprised in the aggregate of activities designated under the name mind, they must always remain

1 Spencer's Principles of Psychology, 2d edition, p. 158.

for him the unknown connotations of their effects on that aggregate, and they cannot be thought except in terms furnished by that aggregate. Consequently, if he considers his conceptions on these activities placed outside of mind as constituting knowledge of them, he deceives himself; he does no more than represent these activities to himself in expressions of the mind, and he cannot do otherwise. He is obliged to admit that his ideas of matter and motion, pure symbols of unknowable realities, are complex states of consciousness produced by units of sensation. But if, after having admitted this, he persists in asking if units of consciousness are of the same nature as units of force distinguished as external; or if the units of force distinguished as external are of the same nature as the units of sensation, then the answer, always fundamentally the same, must be, that it will advance us no further to conceive of the units of external force as identical with the units of sensation, than to conceive of the units of sensation as identical with the units of external force. It is clear that if the units of external force are regarded as absolutely unknown and unknowable, then, to translate the units of sensation into them is to translate the known into the unknown, which is absurd. And if they are only what they are supposed to be by those who identify them with thetr symbols, then the difficulty of translating units of sensation into units of force is insurmountable. If force, such as it exists objectively is absolutely foreign in its nature to that which exists subjectively as sensation, then the transformation of force into sensation is unthinkable; that is to say, it is impossible to interpret intimate existence by terms of external existence. But if, on the other hand, units of force such as they exist objectively are essentially the same in nature as those which manifest themselves objectively as units of sensation, then a becoming hypothesis remains open. Each element of that aggregate of activities which constitutes a consciousness is known as belonging to the consciousness only by its cohesion with the rest. Beyond the limits of that coherent aggregate of activities, there are other activities completely independent of it, and which cannot enter into it. We can imagine then that by their exclusion from the circle of those activities which constitute consciousness, the external activities, although of the same

intrinsic nature, assume an antithetical aspect. Being separated from consciousness, and cut off by its boundaries, they become foreign to it. Not being incorporated with the activities of consciousness, nor united with them, as they are among themselves, consciousness cannot, so to speak, traverse them, and thus they are figured as unconscious; they are represented as having the nature called material, in opposition to that which we call spiritual. Nevertheless, although this shews that it is possible to imagine that the units of external force are identical in nature with the units of force known as sensation, we do not, by representing them thus, arrive at understanding external force any better, because, as it has already been seen, in supposing that all forms of mind be composed of homogeneous units of sensation differently aggregated, this resolution into units leaves us as incapable as before of understanding how the substance of mind can consist of such units; and thus, when we could even really figure to ourselves all the units of external force as being essentially the same as the units of force known as sensation, so that they should constitute a universal sensibility, we should still be for ever as far off from forming an idea of this universal sensorium.

Consequently, though it seems more easy to translate that which we call matter into that which we call mind, than to translate that which we call mind into that which we call matter (an operation which is, in fact, completely impossible) nevertheless our translation cannot lead us further than our symbols. Those vast conceptions which we see from afar are illusions evoked by the false connotation of our words. The expression 'substance of mind,' regarded as anything by the x of our equation, leads us inevitably into error, for we cannot think a substance except in terms which imply material properties. All our progress consists in acknowledging that our symbols are only symbols, and that our constitution necessitates the unknowable such as it manifests itself within the limits of consciousness and under the form of sensation, no less impenetrable than the unknowable such as it manifests itself outside these limits and under other forms. We do not arrive at understanding it better by translating the second into the first. The conditional form in which