Common sense and idealism. causes went on till, after an unimaginable series of ages, the world became fit for animal life, and, ultimately, for mind to find a place on its surface. According to that view of nature which has now met with such general acceptance, and which is known as "the theory of evolution," this world was at first, for a prodigious period of time, the theatre of physical forces only; subsequently life began to appear where before no life was, and as ages have succeeded to ages, higher forms of life, both vegetable and animal, came into being. After the land and waters had teemed with life for a vast period of time, an age of reptiles, it is declared, preceded the age of beasts. Then huge marine reptilian forms occupied the place afterwards filled by whales and porpoises; the air vibrated with the rapid strokes of the wings of flying reptiles, while others more huge than the rhinoceroses of to-day, browsed on the foliage of its trees or hunted down and slew the less agile vegetable feeders. All this at last came to an end with the deposition of what are now our familiar chalk downs, and since that time a great variety of beasts have come into being and perished without leaving a trace behind, although a fraction of those which have become extinct are now known to us as fossil forms. Genus succeeded to genus and species to species; the gigantic long-armed ape wandered over the south of France, and many kinds of monkey chattered in the woods of what we now know as Greece. At last the human form made its appearance on the scene, and then came races destined to dwell for centuries in caves, rudely chipping flints for weapons, but by degrees exhibiting signs of an innate love for art. They had with difficulty to hold their own against the cave bear, tiger, hyæna, and other such formidable foes before they were succeeded by other races, and these by others, till the dawn of history appeared for us, the remote successors of those more primitive races of mankind. Such is the teaching of evolution and of science. How is it possible to state all these relations and conditions in the language of idealism? If idealism were true, evolution would indeed be a mere dream, and the whole of physical science also. But is the boast of idealism, that it in no way conflicts with "common sense," justifiable? Is it true that it only deprives the ordinary man of what he will never miss, or does the matter in dispute concern such ordinary man more nearly than idealists would have us believe? Would the world, as understood by common people, be revolutionized, if not destroyed altogether, should idealists be right? It is true that we can express simple perceptions, whether simultaneous or successive, in idealistic phrase; but ordinary men, in the exercise of their "common sense," have to do with something more than such simple perceptions. There is, in fact, no real distinction of kind between scientific knowledge and ordinary knowledge. The pursuit of science is but a pursuit of knowledge conducted with especial care, and according to rules dictated by reason and experience. In ordinary life, just as in science, we seek to know causes and to understand as best we may the ways in which they act. Conceptions of the causal action of one thing on another, and of different modes of such action, abound in ordinary speech and the mental habits of everyday life. Every artisan or sportsman who discusses the utility of tools or weapons or methods of procedure, gives evidence of this fact. We have drawn out at some length the inconsistency of idealism with physical science in order to show more plainly its inconsistency with the dictates also of common sense, which are nothing essentially different from the dictates of science. Let the reader judge for himself whether or not idealism would or would not deprive him of an essential element of his daily life, if it could deprive him of his perceptions of the causal relations of bodies. Let him consider whether a world, deprived of such relations, would not be for him a world revolutionized, or rather, whether the world, as he knows it, would not be thereby entirely destroyed. Some persons may reply that we ought to be grateful to idealism for doing away with this notion of the action of causes, seeing that it is a mere delusion, since all we can see is that one thing follows another, and not that it exercises any real influence over it. This reply we have already discussed, and shall refer to again, but a short answer *See above, pp. 48-51. See below, chap. xviii. may here suffice. Our present object is not to justify the conceptions either of common sense or of physical science, but to see whether or not idealism accords with them. Now, such a reply as that we are considering, would at once annihilate the pretension of idealists that their system does not conflict with common sense, and would show idealism to be a system incapable of admitting an idea of daily use amongst mankind, which is bound up with our conception of the world, and is essential to the progress of physical science. The beliefs of ordinary men and the conceptions made use of by physical science are thus bound up together, and "realism" justifies both alike. But to justify the conceptions of science will not, of course, help us to understand the conceptions of those men of science who profess idealism. To try and explain the contradiction which exists between their idealism and their science is the task to which we have next to apply ourselves. In the following chapter we shall endeavour to reconcile the seemingly inconsistent truths thus simultaneously held, by the aid of what we believe to be a complementary truth which has been too generally neglected. CHAPTER IX. THE KEY OF THE POSITION. We have a direct and immediate knowledge of objects which are made present to the intellect by the action of the senses, and we can obtain a certain knowledge of matters of which the senses can take no cognizance. in idealism. The truth in idealism—Complementary truth-Sensations the means, not the object, of perception-Two elements in perception-True meaning of "represent"-Perception not inference-What so-called "unconscious inference" is-Perception certified by attention. IDEALISTS are perfectly right in saying that we can know The truth nothing except through our sensations, and that a plexus of our own feelings forms for us every external object which we think we perceive or know. Moreover, not only is it true that our knowledge of everything we perceive is thus constituted, but it is also true that we can neither imagine nor conceive of anything, however abstract or elevated the object imagined or conceived of may seem to us to be, except by the help of sensations, or of feelings and imaginations which are the result of antecedently felt sensations. The truth of the first assertion is unquestionable; for it is obvious that we can perceive no object except by our means of perception; that we have no means of perception apart from our sense organs; and that these can act for us in no other way than by affording us sensations, either vivid or faint. The truth of the second assertion the reader should test for himself. Let him examine again and again the most refined or abstract idea he can think of, and let him see whether he has not in his mind, * See also below, chap. xv. Complementary truth. while thinking of it, the imagination of some object which has before been present to his senses-some feeling, or some group of feelings. If he tries to think of "heat," or "light," he will find that there arises in his imagination more or less vague and transient reminiscences of impressions he has received from warm or luminous bodies. If he tries to fix his mind on the conception, "God," he will see that some mental image accompanies the presence of that idea; it may be that of a venerable human figure, or of light issuing from a cloud, or of a luminous triangle, or of the letters G O D, or of the sound of the spoken wordaccording as images of one or other kind may have become associated in his past experience. If he dwells on such abstract ideas as "being," or "contradiction," or even tries to think of "nonentity," he will perceive, if he looks closely into his own mind, that the presence of those ideas is accompanied in the first case by transient images of bodies he has perceived, in the second case by images of bodies placed opposite each other, or in some way in conflict, and in the third case by a shorter or longer series of things thought of as existing, and then successively, as it were, ejected from thought; for to think, and yet think of nothing, is an impossibility. Idealists are also right in saying that if we analyze our perception, or idea, of any object, whatever it may be, we shall find that we cannot imagine its constituent elements in any other terms than those of our own sensations, and they are also right in affirming that it is no less impossible to imagine anything existing unperceived. Besides all this, their reasoning against even the possibility of anything existing unperceived is perfectly logical and valid. For things which are exclusively made up of "feelings "—as they affirm all objects perceived by us to be—can have no existence except as felt. Obviously "feelings" could have no place in a universe which was entirely devoid of feeling. In maintaining the truth of the foregoing propositions, idealists, then, have reason on their side. There is, however, another most important fact of which they fail altogether to take note, namely, that over and above acts of sensation and imagination, the action of the intellect has |