Cartesian dualism is founded. For this dualism, then, our concrete human nature is not merely a glaring exception-since all other spirits are assumed to be incorporeal and all other organisms merely machines;-it is not merely a knot that an omnipotent Deity might tie: it is a veritable Unding, a contradiction. Since, however, this human nature is a fact, it suffices -even as a negative instance-to render that dualism untenable, and we only need to begin where Descartes ends to be clear of it. For in the end, as we have just seen, he has to admit that it is not true of human nature, and he fails to find it in human experience. Here, as he points out, our internal sensations make us aware of what we need for the preservation of health, and our external percepts enable us clearly and distinctly to know which among surrounding objects are beneficial and which are hurtful to us in so far as we are composed of body and mind; here memory enables us to connect together the whole course of our waking life; and here judgment enables us to discriminate practically between what is true and what is false, so that "all the doubts of those bygone days are to be rejected as hyperbolical and ridiculous."

Had Descartes started, as he ought to have done, from this experience, and reflected seriously on all that it involved, he might have realised that his notion of mind alone was not adequate to cover it. Beginning with the organism and its environment-Aristotle saw that an informing 'soul' was necessary in order that the organism should actually have life. Descartes, who began with mind, ought in like manner to have seen that objects distinct from it were necessary in order that the conscious subject should actually have experience. But Descartes failed to seize this duality. It is true that he admitted, and admitted in so many words, that in human nature the res cogitans is not a res completa1. But, after all, this admission was made from the biological or psychophysical standpoint, the standpoint of Aristotle, not from the psychological standpoint, to which Descartes had himself attained. He therefore still held fast to his dualism. The immediate objects, even of sensible experience, he maintained were only modes of consciousness, changes "that take place in us."

1 Reply to Arnauld's "Objections to the Meditations," Philosophical Works, edited by Haldane and Ross, vol. ii. p. 99.

But how is this position to be made consistent with Descartes' belief that his own body was surrounded by many other bodies, and so forth? Were those presentations of his own body and other bodies but modes of himself as res cogitans? If they were not, then his experience was not confined to such modes. If they were, it was so confined and therefore cut off altogether from body as a res extensa: the dualism of mind and body is justified indeed, but only at the price of making all experience of the latter impossible, or at least inexplicable. Out of this second impasse Descartes only escaped as he escaped from the first-by appealing to the Deity: only the Divine omnipotence could combine body and mind in human nature, and only the Divine veracity could guarantee the reality of the material world in human experience. These two problems-the relation of body and mind and the reality of external perception-have continued to vex philosophic thinkers from Descartes' day to our own, nor will they cease to trouble us till dualism is laid to rest.

The Cartesian Dualism and the Duality of Experience.

§3. On these grounds alone we should be amply justified in rejecting in limine the perfunctory definition of psychology— etymology notwithstanding-as the science of mind, over against which there stands a totally distinct science of matter (which might have been called hylology). It will repay us, however, to continue our historical survey a little further, so as to note the main features in the transition to the third concept of psychology as the science of individual experience. In this the respective merits both of the Aristotelian and the Cartesian doctrines are retained, and their defects redressed. The chief merit of the second of these lies, as already said, in its subjective, i.e. individualistic standpoint: this has not been, and is not likely to be, abandoned. The defects consist partly in its metaphysical, we might even say, its theological assumptions, and partly in the predominantly 'intellectualistic' character it assigns to individual experience. Though the dogmatic assumptions of Descartes' mental philosophy were seriously discredited by the empirical psychology which Locke began, and a long line of British workers carried forward; yet that philosophy continued

to flourish on the Continent. It attained its zenith in the Psychologia rationalis of Wolff: in this the simplicity, immateriality and immortality of the soul were evolved out of the bare concept of consciousness. But such a priori demonstrations of the nature of mind were at length rudely shaken, along with the rest of metaphysical dogmatism, by Kant. He maintained the emptiness of all concepts save as they derive their 'content' from experience, and the invalidity of all concepts when extended beyond it. For us there were no noumena or thoughtgiven realities: all our knowledge was confined to phenomena or sense-given realities. To experience, the duality of subject and object was essential, and these factors in isolation were not res completae but purely problematic concepts, about which there might be faith or speculation, but certainly not knowledge. In whatever way our practical interest in such problems as that of immortality may be met, they have, at any rate since Kant's day, ceased to be regarded as psychological problems', and psychology has now become entirely an empirical science, divested alike of theological and of metaphysical assumptions. The recognition of the inseparability of subject and object in experience, which was a cardinal doctrine with Kant, has helped too to bring the mind theory into line with the life theory; but in place of the life of body, organic life, we have now the life of mind, psychical life. But mind here properly denotes the subject of experience, the Ego-as we sometimes say-in contradistinction to the Non-Ego or object of experience; and mental life is tantamount to experience as the interaction of the two. It is with this mental life that Subjective Psychology, as contrasted with the Objective Psychology of Aristotle, is primarily concerned 2.

But Locke and his successors, Kant included, were still hampered by the defective analysis of the facts of mental life, which they took over from Descartes, while rejecting more or less completely his metaphysical assumptions. That analysis, it has just been said, was unduly intellectualistic: in other words, as Descartes conceived the subject as essentially intellectual, so he regarded its experience as fundamentally cognitive. The only experience he recognised was experience at 1 For Kant himself immortality was a postulate of the practical reason.

2 Cf. on this distinction, H. Spencer's Principles of Psychology, pt. 1. ch. VII.

the self-conscious level; and in this he tended first to identify the experience with the self-consciousness, the whole with the part, and next to identify the cognitions of self-consciousness with the facts cognised. Each of these twin errors we must examine in turn.

In external perception the mind, Descartes conceived, "turned towards the body," but in self-consciousness "it turned in some way upon itself." In keeping with this Locke distinguishes sensation and reflexion as the two sources of simple ideas, the one of the ideas of the sensible qualities of external objects, the other of the ideas of the mind's own operations. Reflexion, though not actually a sense, is yet, he says, "very like one, and might properly enough be called internal sense1." And Kant proceeded without misgiving so to regard it and placed external sense and internal sense on a par as distinct but co-ordinate sources of experience, the one of the experience of physical phenomena, the other of the experience of psychical phenomena. So we get a new dualism, the dualism of phenomena, which serves to keep the old dualism of substances in countenance; and with it we get also a new definition of psychology that is scarcely better than the old. Psychology becomes the science of internal experience as observed through the inner sense, and so is sharply contrasted, though otherwise co-ordinate, with the sciences of external experience, which treat of the objects observed through the outer senses. One step more and the subject and the object of our immediate experience seem again to fall completely apart. This step was taken, for example, by Bain, who distinguishes object-experience from subject-experience, and confines psychology to the latter. He further refers to these as two worlds, "the one circumscribed by one property, extension," the other definable "negatively by a single fact, the absence of extension"." But it is certain that immediate

1 Essay, II. i. 4.

2 Thus we find Hamilton saying: "Mind and matter, as known and knowable, are only two different series of phenomena or qualities; mind and matter, as unknown and unknowable, are the two substances in which these two different series of qualities are supposed to inhere. The existence of an unknown substance is only an inference we are compelled to make, from the existence of known phenomena; and the distinction of two substances is only inferred from the seeming incompatibility of the two series of phenomena to coinhere in one." Lectures on Metaphysics, vol. i. p. 138. 3 Mental Science, pp. 1 f.

experience is never thus sundered, and obvious, therefore, that in all this there is some confusion which we must endeavour to clear up.

We may note first of all that the phrase 'internal sense' is a complete misnomer, save where reference is intended solely to what is internal to the organism. But here 'internal' is meant to distinguish what occurs in the mind' from what occurs out of the body, and involves a correlation of 'in' and 'not in,' ¿.e. 'out of,' which is as absurd as contrasting what occurs in a given day with what occurs outside of a given door. And as to an internal sense-even if it were allowable to speak with Locke of sensory "impressions of objects extrinsical to the mind "what could be the meaning of sensory impressions from "powers intrinsical and proper to [the subject] itself1"? The physiologist who recognises organs and 'centres' of the outer sense knows nothing of any such in the case of this supposed 'inner sense.' Locke bids us "follow a child from its birth and observe the alterations that time makes," and he then himself briefly describes the child's gradual advance till "in time it comes to reflect on its own operations about the ideas got by sensation." But when this stage is reached Locke does not suppose that the child passively receives impressions differing from all previous ones, as the sensations of colour for one couched differ from all his preceding sensations. In the earlier stage the child was conscious, but not self-conscious: "the constant solicitation of the senses," as Locke says, "then employed and directed [it] in looking abroad." But when at length "it turns its view inward upon itself, and observes its own actions about those ideas it has?," it becomes self-conscious; but it does not thereby acquire a new mode of what Kant called sensibility, comparable to the addition of a sixth sense to the five it had before. On the contrary it is only intellectually active “about the ideas it [already] has" Beforehand it could not hear that it tasted, or taste that it heard; nor can it now, for the external senses are severally 1 This is the 'paradox' that Kant vainly attempted to explain. The havoc wrought in psychology and philosophy by Locke's doctrine is nowhere more appalling than here and throughout the Critique. Cf. 2nd ed. § 24.

2 Essay, 11. i. §§ 22, 24, 8; vi. § 1.

3 Thereby indeed it acquires other ideas, but these are not sensory and cannot with any propriety be called impressions of reflexion, as they were by Hume, for example.