02.01 - Part 2, Chapter 1

PART II SOME REASONS FOR BELIEF

CHAPTER I THE PHILOSOPHIC BASIS OF NATURALISM So far we have been occupied in weighing certain indirect and collateral consequences which seem likely to flow from a particular theory of the world in which we live. The theory itself was taken for granted. No attempt was made to examine its foundations or to test their strength; no comparison between its different parts was instituted for the purpose of determining how far they really constituted a coherent and intelligible whole. We accepted it as we found it, turning with averted eyes even from the speculative problems which lay closest to the track of our immediate investigation. This course is not the most logical; and it might perhaps appear a more fitting procedure to reserve our consideration of the consequences of a system until some conclusion had been arrived at concerning its truth. Such, however, is not the ordinary habit of mankind in dealing with problems in which questions of abstract theory and daily practice are closely intertwined; and even philosophers show a kindly reluctance too closely to examine the claims of creeds whose consequences are in strict accord with contemporary sentiment. I have a better reason, however, to offer for the order here selected than can be derived from precedent or example, a reason based on the fact that, had I begun these Notes with the discussion on which I am about to embark, their whole character would probably have been misunderstood. They would have been regarded as contributions to philosophical discussion of a kind which would only interest the specialist; and the general reader, to whom I desire particularly to appeal, would have abandoned their perusal in disgust. For I cannot deny, either that I am about to ask him to accompany me in a search after first principles; or (which is, perhaps, worse) that the search is destined to be ineffectual. He will not only have to occupy himself with arguments of a remote and abstract kind, and for a moment to disturb the placid depths of ordinary thought with unaccustomed soundings, but the arguments will be to all appearance barren, and the soundings will not find bottom. The full justification for a procedure seemingly so futile can only be found in the chapters which follow, and in the general drift of the discussion taken as a whole; but in the meanwhile the reader will be able to appreciate my immediate object if he will bear in mind the precise point at which we have arrived.

Let him remember, then, that the result of the inquiry instituted into the practical tendencies of the naturalistic theory is to show them to be well-nigh intolerable. The theory, no doubt, may for all that be true, since it must candidly be admitted that there is no naturalistic reason for anticipating any preestablished harmony between truth and expediency in the higher regions of speculation. But at least we are called upon to make a very searching inquiry before we admit that it is true. We are not here concerned with any mere curiosity of dialectics, with the quest for a kind of knowledge which, however interesting to the few, yet bears no fruit for ordinary human use. On the contrary, the issues that have to be decided are practical, if anything is practical. They touch at every point the most permanent interests of man, individual and social; and any procedure is preferable to a complacent acquiescence in the loss of all the fairest provinces in our spiritual inheritance. This is a fact which has long been perceived by the defenders of all the creeds, philosophical or theological, with which the pretensions of naturalism are in conflict. You will not open a modern work of apologetics, for instance, without finding in it some endeavour to show that the naturalistic theory is insufficient, and that it requires to be supplemented by precisely the very system in whose interests that particular work was written. This, no doubt, is as it should be; and on this plan a great deal of valuable criticism and interesting speculation has been produced. It is not, however, exactly the plan which can be here pursued, partly because these Notes contain, not a system of theology, but only an introduction to theology; and partly because I have always found it easier to satisfy myself of the insufficiency of naturalism than of the absolute sufficiency of any of the schemes by which it has been sought to modify or to complete it. In this chapter, however, I shall follow an easier line of march, the nature of which the reader will readily understand if he considers the two elements composing the naturalistic creed: the one positive, consisting, broadly speaking, of the teaching contained in the general body of the natural sciences; the other negative, expressed in the doctrine that beyond these limits, wherever they may happen to lie, nothing is, and nothing can be, known. Now, the usual practice with those who dissent from this general view is, as I have said, to choose the second, or negative, half of it for attack. They tell us, for example, that the knowledge of phenomena given by science carries with it by necessary implication the knowledge of that which is above phenomena; or, again, that the moral nature of man points to the reality of ends and principles which cannot be exhausted by any investigation into a merely natural world of causally related objects. Without the least underrating such lines of investigation, I purpose here to consider, not the negative, but the positive half of the naturalistic system. I shall leave for the moment unchallenged the statement that beyond the natural sciences knowledge is impossible; but I shall venture, instead, to ask a few questions as to the character of the knowledge which is thought to be obtained within those limits.

I shall not endeavour to prove that a scheme of merely positive beliefs, admirable, no doubt, as far as it goes, is yet intellectually insufficient unless it be supplemented by a metaphysical or theological appendix. But I shall examine the foundations of the scheme itself; and though such criticisms on it as I shall be able to offer can never be a substitute for the real work of philosophic construction, they would seem to be its fitting preliminary, and a preliminary which the succeeding chapters may show to be not without a profit of its own.

One great metaphysician has described the system of another as ’ shot out of a pistol,’ meaning thereby that it was presented for acceptance without introductory proof. The criticism is true not only of the particular theory of the Absolute about which it was first used, but about every system, or almost every system, of belief which has ever passed current among mankind. Some subtle analogy with accepted doctrines, some general harmony with existing sentiments and modes of thought, has not uncommonly been deemed sufficient to justify the most audacious conjectures; and the history of speculation is littered with theories whose authors seem never to have suffered under any overmastering need to prove the opinions which they advanced. No such overmastering need has, at least, been felt in the case of ’ positive knowledge,’ and the very circumstance that, alike in its methods and in its results, all men are practically agreed to accept it without demur, has blinded them to the fact that it, too, has been ’ shot out of a pistol,’ and that, like some more questionable beliefs, it is still waiting for a rational justification.

1 [For our too easy acquiescence in this state of things I do not think science is itself to blame. It is no part of its duty to deal with first principles. Its business is to provide us with a theory of Nature; and it should not be required, in addition, to provide us with a theory of itself. This is a task which properly devolves upon the masters of speculation; though it is one which, for various reasons, they have not as yet satisfactorily accomplished. I doubt, indeed, whether any metaphysical philosopher before Kant can be said to have made contributions to this subject which at the present day need be taken into serious account; and, as I shall endeavour to indicate in the next chapter, Kant’s doctrines, even as modified by his successors, do not, so it seems to me, provide a sound basis for an ’ epistemology of Nature.’ But if in this connection we owe little to the metaphysical philosophers, we owe still less to those in whom we had a better right to trust, namely, the empirical ones. If the former have to some extent neglected the theory of science for theories of the Absolute, the latter have always shown an inclination

1 The remarks on the history of philosophy which occupy the remainder of this section are not essential to the argument, and may be omitted by readers uninterested in that subject. The strictly necessary discussion is resumed on p. 100. to sacrifice the theory of knowledge itself to theories as to the genesis or growth of knowledge. They have contented themselves with investigating the primitive elements from which have been developed in the race and in the individual the completed consciousness of ourselves and of the world in which we live. They have, therefore, dealt with the origins of what we believe rather than with its justification. They have substituted psychology for philosophy; they have presented us, in short, with studies in a particular branch or department of science, rather than with an examination into the grounds of science in general. And when perforce they are brought face to face with some of the problems connected with the philosophy of science which most loudly clamour for solution, there is something half-pathetic and half-humorous in their methods of cutting a knot which they are quite unable to untie. Can anything, for example, be more na’ive than the undisturbed serenity with which Locke, towards the end of his great work, assures his readers that he ’ suspects that natural philosophy is not capable of being made a science ’; or, as I should prefer to state it, that natural science is not capable of being made a philosophy? Or can anything be more characteristic than the moral which he draws from this rather surprising admission, namely, that as we are so little fitted to frame theories about this present world, we had better devote our energies to preparing for the next? This remarkable display of philosophic resignation in the father of modern empiricism has been imitated, with differences, by a long line of distinguished successors. Hume, for example, though naturally enough he declined to draw Locke’s edifying conclusion, did more than anyone else to establish Locke’s despairing premise; and his inferences from it are at least equally singular. Having reduced our belief in the fundamental principles of scientific interpretation to expectations born of habit; having reduced the world which is to be interpreted to an unrelated series of impressions and ideas; having by this double process made experience impossible and turned science into foolishness, he quietly informs us, as the issue of the whole matter, that outside experience and science knowledge is impossible, and that all except ’ mathematical demonstration ’ and ’ experimental reasoning ’ on ’ matters of fact ’ is sophistry and illusion!

I think too well of Hume’s speculative genius and too ill of his speculative sincerity to doubt that in making this statement he spoke, not as a philosopher, but as a man of the world, making formal obeisance to the powers that be. But what he said half ironically, his followers have said with an unshaken seriousness. Nothing in the history of speculation is more astonishing, nothing if I am to speak my whole mind is more absurd than the way in which Hume’s philosophic progeny a most distinguished race have, in spite of all their differences, yet been able to agree, both that experience is essentially as Hume described it, and that from such an experience can be rationally extracted anything even in the remotest degree resembling the existing system of the natural sciences. Like Locke, these gentlemen, or some of them, have, indeed, been assailed by momentary misgivings. It seems occasionally to have occurred to them that if their theory of knowledge were adequate, ’ experimental reasoning/ as Hume called it, was in a very parlous state; and that, on the merits, nothing less deserved to be held with a positive conviction than what some of them are wont to describe as ’ positive ’ knowledge. But they have soon thrust away such unwelcome thoughts. The self-satisfied dogmatism which is so convenient, and, indeed, so necessary a habit in the daily routine of life, has resumed its sway. They have forgotten that they were philosophers, and with true practical instincts have reserved their ’ obstinate questionings ’ exclusively for the benefit of opinions from which they were already predisposed to differ.

Whether these historic reasons fully account for the comparative neglect of a philosophy of science I will not venture to pronounce. But that the neglect has been real I cannot doubt. Admirable generalisations of the actual methods of scientific research, usually under some such name as ’ Inductive Logic,’ we have no doubt had in abundance. But a full and systematic attempt, first to enumerate, and then to justify, the presuppositions on which all science finally rests, has, it seems to me, still to be made, and must form no insignificant or secondary portion of the task which philosophy has yet to perform. To some, perhaps to most, it may, indeed, appear as if such a task were one of perverse futility; not more useful and much less dignified than metaphysical investigations into the nature of the Absolute. However profitless in the opinion of the objector these may be, at least it seems better to strain after the transcendent than to demonstrate the obvious. And science, it may well be thought, is quite sure enough of its ground to be justified in politely bowing out those who thus officiously tender it a perfectly superfluous assistance. This is a contention on the merits of which it will only be possible to pronounce after the critical examination into the presuppositions of science which I desiderate has been thoroughly carried out. It may then appear that nothing stands more in need of demonstration than the obvious; that at the very root of our scientific system of belief lie problems of which no satisfactory solution has hitherto been devised; and that, so far from its being possible to ignore the difficulties which these involve, no general theory of knowledge has the least chance of being successful which does not explicitly include within the circuit of its criticism, not only the beliefs which seem to us to be dubious, but those also which we hold with the most perfect practical assurance. So much, at least, I have endeavoured to establish in another work to which reference has been already made. 1 And to this I must venture to refer those readers who either wish to see this position elaborately developed, or who are of opinion that I have in the preceding remarks treated the philosophy of the empirical school with too scant a measure of respect. The very technical discussion, however, which it contains could not, I think, be made interesting, or perhaps intelligible, to the majority of those for whom this book is intended, and, even were it otherwise, they could not appropriately be introduced into the body of these Notes. Yet, though this is impossible, it ought not, I think, to be quite impossible to convey some general notion of the sort of difficulty with which any empirical theory of science would seem to be beset, and this without requiring on the part of the reader any special knowledge of philosophic terminology, or, indeed, any knowledge at all except that of some few very general scientific doctrines. If I could succeed, however imperfectly, in such a task, it might be of some slight service even to the reader conversant with empirical theories in all their various forms. For though he will, of course, recognise in what follows the familiar faces of many old controversies, the circumstance that they are here approached, not from the accustomed side of the psychology of perception, but from that of physics and physiology, 1 Cf. Prefatory Note. may perhaps give them a freshness they would not otherwise possess.]

II In order to fix our ideas let us recall, in however rough and incomplete a form, the broad outlines of scientific doctrine as it at present exists, and as it has been developed from that unorganised knowledge of a world of objects animals, mountains, men, planets, trees, water, fire, and so forth which in some degree or other all mankind possess. These objects science conceives as ordered and mutually related in one unlimited space and one unlimited time; all in their true reality independent of the presence or absence of any observer, all governed in their behaviour by rigid and unvarying laws. These are its material; these it is its business to describe. Their appearance, their inner constitution, their environment, the process of their development, the modes in which they act and are acted upon such and such-like subjects of inquiry constitute the problems which science has set itself to investigate. The result of its investigations is now embodied in a general, if provisional, view of the (phenomenal) universe which may be accepted at least as a working hypothesis. According to this view, the world consists essentially of innumerable small particles of definite mass, endowed with a variety of mechanical, chemical, and other qualities, and forming by their mutual association the various bodies which we can handle and see, and many others which we can neither handle nor see. These ponderable particles have their being in a diffused and all-penetrating medium, or ether, which possesses, or behaves as if it possessed, certain mechanical properties of a very remarkable character; while the whole of this material 1 system, ponderable particles and ether alike, is animated (if the phrase may be permitted me) by a quantity of energy which, though it varies in the manner and place of its manifestation, yet never varies in its total amount. It only remains to add, as a fact of considerable importance to ourselves, though of little apparent importance to the universe at large, that a few of the material particles above alluded to are arranged into living organisms, and that among these organisms are a small minority which have the remarkable power of extracting from the changes which take place in certain of their tissues psychical phenomena of various kinds; some of which are the reflection, or partial reproduction

1 This ambiguity in the use of the word ’ matter ’ is apt to be a nuisance in these discussions. The term is sometimes, and quite properly, used only of ponderable matter, and in opposition to ether. But when we talk of the ’ material universe,’ it is absurd to exclude from our meaning the ether, which is the most important part of that universe. The context will, I hope, always show in which sense the word is used. I should perhaps add that I have deliberately refrained from complicating the text by any allusion to recent hypotheses as to the nature of the ether and its relation to ponderable matter or to recent discoveries respecting the divisibility of the atom. in perception and in thought, of fragments and aspects of that material world to which they owe their being.

Secure in this general view of things, the great co-operative work of scientific investigation moves swiftly on. The psychologist deals with the laws governing mental phenomena and with the relations of mind and body; the physiologist endeavours to surprise the secrets of the living organ; the biologist traces the development of the individual and the mutations of the species; the chemist searches out the laws which govern the combination and reactions of atoms and molecules; the astronomer investigates the movements and the life-histories of suns and planets; while the physicist explores the inmost mysteries of matter and energy, not unprepared to discover behind the invisible particles and the insensible movements with which he familiarly deals, explanations of the material universe yet more remote from the unsophisticated perceptions of ordinary mankind. The philosophic reader is of course aware that many of the terms which 1 have used, and been obliged to use, in this outline of the scientific view of the universe may be, and have been, subjected to philosophic analysis, and often with very curious results. Space, time, matter, energy, cause, quality, idea, perception all these, to mention no others, are expressions without the aid of which no account could be given of the circle of the sciences; though every one of them suggests a multitude of speculative problems, of which speculation has not as yet succeeded in giving us the final and decisive solution. These problems, for the most part, however, I put on one side. 1 I take these terms as I find them; in the sense, that is, which everybody attributes to them until he begins to puzzle himself with too curious inquiries into their precise meaning. No such embarrassing investigations do I here wish to impose upon my reader. It shall for the present be agreed between us that the body of doctrine summarised above is, so far as it goes, clear and intelligible; and all I shall now require of him is to look at it from a new point of view, to approach it, as it were, from a different side, to study it with a new intention. Instead, then, of asking what are the beliefs which science inculcates, let us ask why, in the last resort, we hold them to be true. Instead of inquiring how a thing happens, or what it is, let us inquire how we know that it does thus happen, and why we believe that so in truth it is. Instead of enumerating causes, let us set ourselves to investigate reasons.

Now it is at once evident that the very same general body of doctrines, the very same set of propositions about the ’ natural ’ world, arranged according to the principles suggested by these questions, would fall into a wholly different order from [’ See, however, infra, the chapter on ’ Ultimate Scientific Ideas.’] that which would be observed if its distribution were governed merely by considerations based upon the convenience of scientific exposition. Indeed, we may say that there are at least four quite different orders, theoretically distinguishable, though usually mixed up in practice, in which scientific truth may be expounded. There is, first, the order of discovery. This is governed by no rational principle, but depends on historic causes, on the accidents of individual genius and the romantic chances of experiment and observation. There is, secondly, the rhetorical order, useful enough in its proper place, in which, for example, we proceed from the simple to the difficult, or from the striking to the important, according to the needs of the hearer. There is, thirdly, the scientific order, in which, could we only bring it to perfection, we should proceed from the abstract to the concrete, and from the general law to the particular instance, until the whole world of phenomena was gradually presented to our gaze as a closely woven tissue of causes and effects, infinite in its complexity, incessant in its changes, yet at each moment proclaiming to those who can hear and understand the certain prophecy of its future and the authentic record of its past. Lastly, there is what, according to the terminology here employed, must be called the philosophic order, in which the various scientific propositions or dogmas are, or rather should be, arranged as a series of premises and conclusions, starting from those which are axiomatic, i.e. for which proof can be neither given nor required, and moving on through a continuous series of binding inferences, until the whole of knowledge is caught up and ordered in the meshes of this all-inclusive dialectical network. In its perfected shape it is evident that the philosophic series, though it reaches out to the farthest confines of the known, must for each man trace its origin to something which he can regard as axiomatic and self-evident truth. There is no theoretical escape for any of us from the ultimate ’ I.’ What ’ I ’ believe as conclusive must be drawn, by some process which ’ I ’ accept as cogent, from something which ’ I ’ am obliged to regard as intrinsically self-sufficient, beyond the reach of criticism or the need for proof. The philosophic order and the scientific order of statement, therefore, cannot fail to be wholly different. While the scientific order may start with the dogmatic enunciation of some great generalisation valid through the whole unmeasured range of the material universe, the philosophic order is perforce compelled to find its point of departure in the humble personality of the inquirer. His grounds of belief, not the things believed in, are the subject-matter of investigation. His reason, or, if you like to have it so, his share of the Universal Reason, but in any case something which is his, must sit in judgment, and must try the cause. The rights of this tribunal are inalienable, its authority incapable of delegation; nor is there any superior court by which the verdict it pronounces can be reversed.

If now the question were asked, ’ On what sort of premises rests ultimately the scientific theory of the world?’ science and empirical philosophy, though they might not agree on the meaning of terms, would agree in answering, ’ On premises supplied by experience.’ It is experience which has given us our first real knowledge of Nature and her laws. It is experience, in the shape of observation and experiment, which has given us the raw material out of which hypothesis and inference have slowly elaborated that richer conception of the material world which constitutes perhaps the chief, and certainly the most characteristic, glory of the modern mind.

What, then, is this experience? or, rather, let us ask (so as to avoid the appearance of trenching on Kantian ground) what are these experiences? Putting psychology on one side, these experiences, the experiences on which are alike founded the practice of the savage and the theories of the man of science, are for the most part observations of material things or objects, and of their behaviour in the presence of or in relation to each other. These, on the empirical theory of knowledge, supply the direct information, the immediate data from which all our wider knowledge ultimately draws its sanction. Behind these it is impossible to go; impossible, but also unnecessary. For as the ’ evidence of the senses ’ does not derive its authority from any higher source, so it is useless to dispute its full and indefeasible title to command our assent. According to this view, which is thoroughly in accordance with common-sense, science rests in the main upon the immediate judgments we form about natural objects in the act of seeing, hearing, and handling them. This is the solid, if somewhat narrow, platform which provides us with a foothold whence we may reach upward into regions where the ’ senses ’ convey to us no direct knowledge, where we have to do with laws remote from our personal observation, and with objects which can neither be seen, heard, nor handled.

IV But although such a theory seems simple and straightforward enough, in perfect harmony with the habitual sentiments and the universal practice of mankind, it would evidently be rash to rest satisfied with it as a philosophy of science until we had at least heard what science itself has to say upon the subject. What, then, is the account which science gives of these ’ immediate judgments of the senses ’? Has it anything to tell us about their nature, or the mode of their operation? Without doubt it has; and its teaching provides a curious, and at first sight an even startling, commentary on the common-sense version of that philosophy of experience whose general character has just been indicated above. For whereas common-sense tells us that our experience of objects provides us with a knowledge of their nature which, so far as it goes, is immediate and direct, science informs us that each particular experience is itself but the final link in a long chain of causes and effects, whose beginning is lost amid the complexities of the material world, and whose ending is a change of some sort in the ’ mind ’ of the percipient. It informs us, further, that among these innumerable causes, the thing ’ immediately experienced ’ is but one; and is, moreover, one separated from the ’ immediate experience ’ which it modestly assists in producing by a very large number of intermediate causes which are never experienced at all.

Take, for example, an ordinary case of vision. What are the causes which ultimately produce the apparently immediate experience of (for example) a green tree standing in the next field? There are, first (to go no further back), the vibrations among the particles of the source of light, say the sun. Consequent on these are the ethereal undulations between the sun and the objects seen, namely, the green tree. Then follows the absorption of most of these undulations by the object; the reflection of the ’ green ’ residue; the incidence of a small fraction of these on the lens of the eye; their arrangement on the retina; the stimulation of the optic nerve; and, finally, the molecular change in a certain tract of the cerebral hemispheres by which, in some way or other wholly unknown, through predispositions in part acquired by the individual, but chiefly inherited through countless generations of ancestors, is produced the complex mental fact which we describe by saying that ’ we have an immediate experience of a tree about fifty yards off.’

Now the experience, the causes and conditions of which I have thus rudely outlined, is typical of all the experiences, without exception, on which is based our knowledge of the material universe. Some of these experiences, no doubt, are incorrect. The ’ evidence of the senses,’ as the phrase goes, proves now and then to be fallacious. But it is proved to be fallacious by other evidence of precisely the same kind; and if we take the trouble to trace back far enough our reasons for believing any scientific truth whatever, they always end in some ’immediate experience’ or experiences of the type described above. But the comparison thus inevitably suggested between ’ immediate experiences ’ considered as the ultimate basis of all scientific belief, and immediate experience considered as an insignificant and, so to speak, casual product of natural laws, suggests some curious reflections. I do not allude to the difficulty of understanding how a mental effect can ke produced by a physical cause how matter can act on mind. The problem I wish to dwell on is of quite a different kind. It is concerned, not with the nature of the laws by which the world is governed, but with their proof. It arises, not out of the difficulty of feeling our way slowly along the causal chain from physical antecedents to mental consequents, but from the difficulty of harmonising this movement with the opposite one, whereby we jump by some instantaneous effort of inferential activity from these mental consequents to an immediate conviction as to the reality and character of some of their remoter physical antecedents. I am ’experiencing’ (to revert to our illustration) the tree in the next field. While looking at it I begin to reflect upon the double process I have just described. I remember the long-drawn series of causes, physical and physiological, by which my perception of the object has been produced. I realise that each one of these causes might have been replaced by some other cause without altering the character of the consequent perception; and that if it had been so replaced, my judgment about the object, though it would have been as confident and as immediate as at present, would have been wrong. Anything, for instance, which would distribute similar green rays on the retina of my eyes in the same pattern as that produced by the tree, or anything which would produce a like irritation of the optic nerve or a like modification of the cerebral tissues, would give me an experience in itself quite indistinguishable from my experience of the tree, though with the unfortunate peculiarity of being wholly incorrect. The same message would be delivered, in the same terms and on the same authority, but it would be false. And though we are quite familiar with the fact that illusions are possible and that mistakes will occur in the simplest observation, yet we can hardly avoid being struck by the incongruity of a scheme of belief whose premises are wholly derived from witnesses admittedly untrustworthy, yet which is unable to supply any criterion, other than the evidence of these witnesses themselves, by which the character of their evidence can in any given case be determined. The fact that even the most immediate experiences carry with them no inherent guarantee of their veracity is, however, by far the smallest of the difficulties which emerge from a comparison of the causal movement from object to perception, with the cognitive leap through perception to object. For a very slight consideration of the teaching of science as to the nature of the first is sufficient to prove, not merely the possible, but the habitual inaccuracy of the second. In other words, we need only consider carefully our perceptions regarded as psychological results, in order to see that, regarded as sources of information, they are not merely occasionally inaccurate, but habitually mendacious. We are dealing, recollect, with a theory of science according to which the ultimate stress of scientific proof is thrown wholly upon our immediate experience of objects. But nine-tenths of our immediate experiences of objects are visual; and all visual experiences, without exception, are, according to science, erroneous. As everybody knows, colour is not a property of the thing seen: it is a sensation produced in us by that thing. The thing itself consists of uncoloured particles, which become visible solely in consequence of their power of either producing or reflecting ethereal undulations. The degrees of brightness and the qualities of colour perceived in the thing, and in virtue of which alone any visual perception of the thing is possible, are, therefore, according to optics, no part of its reality, but are mere feelings produced in the mind of the percipient by the complex movements of material molecules, possessing mass and extension, but to which it is not only incorrect but unmeaning to attribute either brightness or colour. From the side of science these are truisms. From the side of a theory or philosophy of science, however, they are paradoxes. It was sufficiently embarrassing to discover that the messages conveyed to us by sensible experiences which the observer treats as so direct and so certain are, when considered in transit, at one moment nothing but vibrations of imperceptible particles, at another nothing but periodic changes in an unimaginable ether, at a third nothing but unknown, and perhaps unknowable, modifications of nervous tissue; and that none of these various messengers carry with them any warrant that the judgment in which they finally issue will prove to be true. But what are we to say about these same experiences when we discover, not only that they may be wholly false, but that they are never wholly true? What sort of a system is that which makes haste to discredit its own premises? In what entanglements of contradiction do we not find ourselves involved by the attempt to rest science upon observations which science itself asserts to be erroneous? By what possible title do we proclaim the same immediate experience to be right when it testifies to the independent reality of something solid and extended, and to be wrong when it testifies to the independent reality of something illuminated and coloured?

There is, of course, an answer to all this, simple enough if only it be true. The whole theory, it may be said, on which we have been proceeding is untenable, the undigested product of crude common-sense. The bugbear which frightens us is of our own creation. We have no immediate experience of independent things such as has been gratuitously supposed. What science tells us of the colour element in our visual perceptions, namely, that it is merely a feeling or sensation, is true of every element in every perception. We are directly cognisant of nothing but mental states: all else is a matter of inference; a hypothetical machinery devised for no other purpose than to account for the existence of the only realities of which we have first-hand knowledge namely, the mental states themselves.

Now this theory does at first sight undoubtedly appear to harmonise with the general teaching of science on the subject of mental physiology. This teaching, as ordinarily expounded, assumes throughout a material world of objects and a psychical world of feelings and ideas. The latter is in all cases the product of the former. In some cases it may be a copy or partial reflection of the former. In no case is it identified with the former. When, therefore, I am in the act of experiencing a tree in the next field, what on this theory I am really doing is inferring from the fact of my having certain feelings the existence of a cause having qualities adequate to produce them. It is true that the process of inference is so rapid and habitual that we are unconscious of performing it. It is also true that the inference is quite differently performed by the natural man in his natural moments and the scientific man in his scientific moments. For, whereas the natural man infers the existence of a material object which in all respects resembles his idea of it, the scientific man knows very well that the material object only resembles his ideas of it in certain particulars extension, solidity, and so forth and that in respect of such attributes as colour and illumination there is no resemblance at all. Nevertheless, in all cases, whether there be resemblance between them or not, the material fact is a conclusion from the mental fact, with which last alone we can be said to be, so to speak, in any immediate empirical relation. As this theory regarding the sources of our knowledge of the material world fits in with the habitual language of mental physiology, so also it fits in with the first instincts of speculative analysis. It is, I suppose, one of the earliest discoveries of the metaphysically minded youth that he can, if he so wills it, change his point of view, and thereby sud. denly convert what in ordinary moments seem the solid realities of this material universe, into an un-. ending pageant of feelings and ideas, moving in long procession across his mental stage, and having from the nature of the case no independent being before they appear, nor retaining any after they vanish. But however plausible be this correction of common-sense, it has its difficulties. In the first place, it involves a complete divorce between the practice of science and its theory. It is all very well to say that the scientific account of mental physiology in general, and of sense-perception in particular, requires us to hold that what is immediately experienced are mental facts, and that our knowledge of physical facts is but mediate and inferential. Such a conclusion is quite out of harmony with its own premises, since the propositions on which, as a matter of historical verity, science is ultimately founded are not propositions about states of mind, but about material things. The observations on which are built, for example, our knowledge of anatomy or our knowledge of chemistry were not, in the opinion of those who originally made them or have since confirmed them, observations of their own feelings, but of objects thought of as wholly independent of the observer. They may have been mistaken. Such observations may be impossible. But, possible or impossible, they were believed to have occurred, and on that belief depends the whole empirical evidence of science as scientific discoverers themselves conceive it. The reader will, I hope, understand that I am not here arguing that the theory of experience now under consideration, the theory, that is, which confines the field of immediate experience to our own states of mind, is inconsistent with science, or even that it supplies an inadequate empirical basis for science. On these points I may have a word to say presently. My present contention simply is, that it is not experience thus understood which has supplied men of science with their knowledge of the physical universe. They have never suspected that, while they supposed themselves to be perceiving independent material objects, they were in reality perceiving quite another set of things, namely, feelings and sensations of a particular kind, grouped in particular ways, and succeeding each other in a particular order. Nor, if this idea had ever occurred to them, would they have admitted that these two classes of things could by any merely verbal manipulation be made the same. So that if this particular account of the nature of experience be accurate, the system of thought represented by science presents the singular spectacle of a creed which is believed in practice for one set of reasons, though in theory it can only be justified by another; and which, through some beneficent accident, turns out to be true, though its origin and each subsequent stage in its gradual development are the product of error and illusion. This is perplexing enough. Yet an even stronger statement would seem to be justified. We must not only say that the experiences on which science is founded have been invariably misinterpreted by those who underwent them, but that, if they had not been so misinterpreted, science as we know it would never have existed. We have not merely stumbled on the truth in spite of error and illusion, which is odd, but because of error and illusion, which is odder. For if the scientific observers of Nature had realised from the beginning that all they were observing was their own feelings and ideas, as empirical idealism and mental physiology alike require us to hold, they surely would never have taken the trouble to invent a Nature (i.e. an independently existing system of material things) for no other purpose than to provide a machinery by which the occurrence of feelings and ideas might be adequately accounted for. To go through so much to get so little, to be wilder themselves in the ever-increasing intricacies of this hypothetical wheel -work, to pile world on world and add infinity to infinity, and all for no more important object than to find an explanation for a few fleeting impressions, say of colour or resistance, would, indeed, have seemed to them a most superfluous labour. Nor is it possible to doubt that this task has been undertaken and partially accomplished only because humanity has been, as for the most part it still is, under the belief not merely that there exists a universe possessing the independence which science and common-sense alike postulate, but that it is a universe immediately, if imperfectly, revealed to us in the deliverances of sense-perception.

VI

We can scarcely deny, then, though the paradox be hard of digestion, that, historically speaking, if the theory we are discussing be true, science owes its being to an erroneous view as to what kind of information it is that our experiences directly convey to us. But a much more important question than the merely historical one remains behind, namely, whether, from the kind of information which our experiences do thus directly convey to us, anything at all resembling the scientific theory of Nature can be reasonably extracted. Can our revised conception of the material world really be inferred from our revised conception of the import and limits of experience? Can we by any possible treatment of sensations and feelings legitimately squeeze out of them trustworthy knowledge of the permanent and independent material universe of which, according to science, sensations and feelings are but transient and evanescent effects?

I cannot imagine the process by which such a result may be attained, nor has it been satisfactorily explained to us by any apologist of the empirical theory of knowledge. We may, no doubt, argue that sensations and feelings, like everything else, must have a cause; that the hypothesis of a material world suggests such a cause in a form which is agreeable to our natural beliefs; and that it is a hypothesis we are justified in adopting when we find that it enables us to anticipate the order and character of that stream of perceptions which it is called into existence to explain. But this is a line of argument which really will not bear examination. Every one of the three propositions of which it consists is, if we are to go back to fundamental principles, either disputable or erroneous. The principle of causation cannot be extracted out of a succession of individual experiences, as is implied by the first. The world described by science is not congruous with our natural beliefs, as is alleged by the second. Nor can we legitimately reason back from effect to cause in the manner required by the third. A very brief comment will, I think, be sufficient to make this clear, and I proceed to offer it on each of the three propositions, taking them, for convenience, in the reverse order, and beginning, therefore, with the third. This in effect declares that as the material world described by science would, if it existed, produce sensations and impressions in the very manner in which our experiences assure us that they actually occur, we may assume that such a world exists. But may we? Even supposing that there was this complete correspondence between theory and fact, which is far, unfortunately, from being at present the case, are we justified in making so bold a logical leap from the known to the unknown? I doubt it. Recollect that by hypothesis we are strictly imprisoned, so far as direct experiences are concerned, within the circle of sensations or impressions. It is in this self-centred universe alone, therefore, that we can collect the premises of further knowledge. How can it possibly supply us with any principles of selection by which to decide between the various kinds of cause that may, for anything we know to the contrary, have had a hand in its production? None of these kinds of cause are open to observation. All must, from the nature of the case, be purely conjectural. Because, therefore, we happen to have thought of one which, with a little goodwill, can be forced into a rude correspondence with the observed facts, shall we, oblivious of the million possible explanations which a superior intelligence might be able to devise, proceed to decorate our particular fancy with the title of the ’ Real World ’? If we do so, it is not, as the candid reader will be prepared to admit, because such a conclusion is justified by such premises, but because we are predisposed to a conclusion of this kind by those instinctive beliefs which, in unreflective moments, the philosopher shares with the savage. In such moments all men conceive themselves (by hypothesis erroneously) as having direct experiences of an independent material universe. When, therefore, science, or philosophers on behalf of science, proceed to infer such a universe from impressions of extension, resistance, and so forth, they find themselves, so far, in an unnatural and quite illegitimate alliance with common-sense. By procedures which are different, and essentially inconsistent, the two parties have found it possible to reach results which at first sight look very much the same. Immediate intuitions wrongly interpreted come to the aid of mediate inferences illegitimately constructed; we find ourselves quite prepared to accept the conclusions of bad reasoning, because they have a partial though, as I shall now proceed to show, an illusory resemblance to the deliverances of uncriticised experience.

This, it will be observed, is the subject dealt with in the second of the three propositions on which I am engaged in commenting. It alleges that the world described by science is congruous with our natural beliefs; a thesis not very important in itself, which I only dwell on now because it affords a convenient text from which to preach the great oddity of the creed which science requires us to adopt respecting the world in which we live. This creed is evidently in its origin an amendment or modification of our natural or instinctive view of things, a compromise to which we are no doubt compelled by considerations of conclusive force, but a compromise, nevertheless, which, if we did not know it to be true, we should certainly find it difficult not to abandon as absurd.

For, consider what kind of a world it is in which we are asked to believe a world which, so far as most people are concerned, can only be at all adequately conceived in terms of the visual sense, but which in its true reality possesses neither of the qualities characteristically associated with the visual sense, namely, illumination and colour. A world which is half like our ideas of it and half unlike them. Like our ideas of it, that is to say, so far as the so-called primary qualities of matter, such as extension and solidity, are concerned; unlike our ideas of it so far as the so-called secondary qualities, such as warmth and colour, are concerned. A hybrid world, a world of inconsistencies and strange anomalies. A world one-half of which may commend itself to the empirical philosopher, and the other half of which may commend itself to the plain man, but which as a whole can commend itself to neither. A world which is rejected by the first because it arbitrarily selects what he regards as modes of sensation, and hypostatises them into permanent realities; while it is scarcely intelligible to the second, because it takes what he regards as permanent realities, and evaporates them into modes of sensation. A world, in short, which seems to harmonise neither with the conclusions of critical empiricism nor with the ’ unmistakable evidence of the senses ’; which outrages the whole psychology of the one, and is in direct contradiction with the deliverances of the other. So far as the leading philosophic empiricists are concerned and it is only with them that we need deal the result of these difficulties has been extraordinary. They have found it impossible to swallow this strange universe, consisting partly of microcosms furnished with impressions and ideas which, as such, are of course transient and essentially mental, partly of a macrocosm furnished with material objects whose qualities exactly resemble impressions and ideas, with the embarrassing exception that they are neither transient nor mental. They have, therefore, been compelled by one device or another to sweep the macrocosm as conceived by science altogether out of existence. In the name of experience itself they have destroyed that which professes to be experience systematised. And we are presented with the singular spectacle of thinkers whose claim to our consideration largely consists in their uncompromising empiricism playing unconscious havoc with the most solid results which empirical methods have hitherto attained.

I say ’unconscious’ havoc, because, no doubt, the truth of this indictment would not be admitted by the majority of those against whom it is directed. Yet there can, I think, be no real question as to its truth. In the case of Hume it will hardly be denied; and Hume, perhaps, would himself have been the last to deny it. But in the case of John Mill, of Mr. Herbert Spencer, 1 and of Professor Huxley, it is an allegation which would certainly be repudiated, though the evidence for it seems to me to lie upon the surface of their speculations. The allegation, be it observed, is this that while each of these thinkers has recognised the necessity for some independent reality in relation to the evermoving stream of sensations which constitute our immediate experiences, each of them has rejected the independent reality which is postulated and explained by science, and each of them has substituted for it a private reality of his own. Where the physicist, for example, assumes actual atoms and motions and forces, Mill saw nothing but permanent possibilities of sensation, and Mr. Spencer knows

1 It is probably accurate to describe Mr. Spencer as an empiricist; though he has added to the accustomed first principles of empiricism certain doctrines of his own which, while they do not strengthen his system, make it somewhat difficult to classify. The reader interested in such matters will find most of the relevant points discussed in Philosophic Doubt, chaps, viii., ix., x. nothing but ’ the unknowable.’ Without discussing the place which such entities may properly occupy in the general scheme of things, I content myself with observing, what I have elsewhere endeavoured to demonstrate at length, that they cannot occupy the place now filled by material Nature as conceived by science. That which is a ’ permanent possibility/ but is nothing more, is permanent only in name. It represents no enduring reality, nothing which persists, nothing which has any being save during the brief intervals when, ceasing to be a mere ’possibility,’ it blossoms into the actuality of sensation. Before sentient beings were, it was not. When they cease to exist, it will vanish away. If they change the character of their sensibility, it will sympathetically vary its nature. How unfit is this unsubstantial shadow of a phrase to take the place now occupied by that material universe, of which we are but fleeting accidents, whose attributes are for the most part absolutely independent of us, whose duration is incalculable! A different but not a less conclusive criticism may be passed on Mr. Spencer’s ’unknowable.’ For anything I am here prepared to allege to the contrary, this may be real enough; but, unfortunately, it has not the kind of reality imperatively required by science. It is not in space. It is not in time. It possesses neither mass nor extension; nor is it capable of motion. Its very name implies that it eludes the grasp of thought, and cannot be caught up into formulae. Whatever purpose, therefore, such an ’object* may subserve in the universe of things, it is as useless as a ’ permanent possibility ’ itself to provide subject-matter for scientific treatment. If these be all that truly exist outside the circle of impressions and ideas, then is all science turned to foolishness, and evolution stands confessed as a mere figment of the imagination. Man, or rather ’ I,’ become not merely the centre of the world, but am the world. Beyond me and my ideas there is either nothing, or nothing that can be known. The problems about which we disquiet ourselves in vain, the origin of things and the modes of their development, the inner constitution of matter and its relations to mind, are questionings about nothing, interrogatories shouted into the void. The baseless fabric of the sciences, like the great globe itself, dissolves at the touch of theories like these, leaving not a wrack behind. Nor does there seem to be any other course open to the consistent agnostic, were such a being possible, than to contemplate in patience the long procession of his sensations, without disturbing himself with futile inquiries into what, if anything, may lie beyond.

VII

There remains but one problem further with which I need trouble the readers of this chapter. It is that raised by the only remaining proposition of the three with which I promised just now to deal. This asserts, it may be recollected, that the principle of causation and, by parity of reasoning, any other universal principle of sense-interpretation, may by some process of logical alchemy be extracted, not merely from experience in general, 1 but even from the experience of a single individual. But who, it may be asked, is unreasonable enough to demand that it should be extracted from the experience of a single individual? What is there in the empirical theory which requires us to impose so arbitrary a limitation upon the sources of our knowledge? Have we not behind us the whole experience of the race? Is it to count for nothing that for numberless generations mankind has been scrutinising the face of Nature, and storing up for our guidance innumerable observations of the laws which she obeys? Yes, I reply, it is to count for nothing; and for a most simple reason. In making this appeal to the testimony of mankind with regard to the world in which they live, we take for granted that there is such a world, that mankind has had experiences of it, and that, so far as is necessary for our purpose, we know what those experiences have been. But by what right do we take those things for granted? They are not axiomatic or intuitive truths; they must be proved by something; and that something must, on the empirical theory, be in the last resort experience, and experience alone. But whose ex- 1 See Philosophic Doubt, ch. i. perience? Plainly it cannot be general experience, for that is the very thing whose reality has to be established, and whose character is in question. It must, therefore, in every case and for each individual man be his own personal experience. This, and only this, can supply him with evidence for those fundamental beliefs, without whose guidance it is impossible for him either to reconstruct the past or to anticipate the future.

Consider, for example, the law of causation; one, but by no means the only one, of those general principles of interpretation which, as I am contending, are presupposed in any appeal to general experience, and cannot, therefore, be proved by it. If we endeavour to analyse the reasoning by which we arrive at the conviction that any particular event or any number of particular events have occurred outside the narrow ring of our own immediate perceptions, we shall find that not a step of this process can we take without assuming that the course of Nature is uniform 1; or, if not absolutely uniform, at least sufficiently uniform to allow us to argue with tolerable security from effects to causes, or, if need be, from causes to effects, over great intervals of time and space. The whole of what is called historical evidence is, in its most essential parts, noth-

1 The reader will find some observations on the meaning of the phrase, ’ Uniformity of Nature,’ on p. 289 et seq. In this chapter I have assumed (following empirical usage) that the Uniformity of Nature and the Law of Causation are different expressions for the same thing. ing more than an argument or series of arguments of this kind. The fact that mankind have given their testimony to the general uniformity of Nature, or, indeed, to anything else, can be established by the aid of that principle itself, and by it alone; so that if we abandon it, we are in a moment deprived of all logical access to the outer world, of all cognisance of other minds, of all usufruct of their accumulated knowledge, of all share in the intellectual heritage of the race. While if we cling to it (as, to be sure, we must, whether we like it or not), we can do so only on condition that we forego every endeavour to prove it by the aid of general experience; for such a procedure would be nothing less than to compel what is intended to be the conclusion of our argument to figure also among the most important of its premises. The problem, therefore, is reduced to this: Can we find in our personal experience adequate evidence of a law which, like the law of Causation, does, by the very terms in which it is stated, claim universal jurisdiction, as of right, to the utmost verge both of time and space. And surely, to enunciate such a question is to suggest the inevitable answer. The sequences familiar to us in the petty round of daily life, the accustomed recurrence of something resembling a former consequent, following on the heels of something resembling a former antecedent, are sufficient to generate the expectations and the habits by which we endeavour, with what success we may, to accommodate our behaviour to the unyielding requirements of the world around us. But to throw upon experiences such as these l the whole burden of fixing our opinions as to the constitution of the universe is quite absurd. It would be absurd in any case. It would be absurd even if all the phenomena of which we have immediate knowledge succeeded each other according to some obvious and undeviating order; for the contrast between this microscopic range of observation and the gigantic induction which it is sought to rest thereon, would rob the argument of all plausibility. But it is doubly and trebly absurd when we reflect on what our experiences really are. So far are they from indicating, when taken strictly by themselves, the existence of a world where all things small and great follow with the most exquisite regularity and the most minute obedience the bidding of unchanging law, that they indicate precisely the reverse. In certain regions of experience, no doubt, orderly sequence appears to be the rule: day alternates with night, and summer follows upon spring; the sun moves through the zodiac, and unsupported bodies fall usually, though, to be sure, not always, to the ground. Even of such elementary astronomical and physical facts, however, it could hardly be maintained that any man would have a right, on the strength of his personal observation alone, confident- 1 At least in the absence of any transcendental interpretation of them. See next chapter. ly to assert their undeviating regularity. But when we come to the more complex phenomena with which we have to deal, the plain lesson taught by personal observation is not the regularity, but the irregularity, of Nature. A kind of ineffectual attempt at uniformity, no doubt, is commonly apparent, as of an ill-constructed machine that will run smoothly for a time, and then for no apparent reason begin to jerk and quiver; or of a drunken man who, though he succeeds in keeping to the high-road, yet pursues along it a most wavering and devious course. But of that perfect adjustment, that all-penetrating governance by law, which lies at the root of scientific inference we find not a trace. In many cases sensation follows sensation, and event hurries after event, to all appearances absolutely at random: no observed order of succession is ever repeated, nor is it pretended that there is any direct causal connection between the members of the series as they appear one after the other in the consciousness of the individual. But even when these conditions are reversed, perfect uniformity is never observed. The most careful series of experiments carried out by the most accomplished investigators never show identical results; and as for the general mass of mankind, so far are they from finding, either in their personal experiences or elsewhere, any sufficient reason for accepting in its perfected form the principle of Universal Causation, that, as a matter of fact, this doctrine has been steadily ignored by them up to the present hour. This apparent irregularity of Nature, obvious enough when we turn our attention to it, escapes our habitual notice, of course, because we invariably attribute the want of observed uniformity to the errors of the observer. And without doubt we do well. But what does this imply? It implies that we bring to the interpretation of our sense-perception the principle of causation ready made. It implies that we do not believe the world to be governed by immutable law because our experiences appear to be regular; but that we believe that our experiences, in spite of their apparent irregularity, follow some (perhaps) unknown rule because we first believe the world to be governed by immutable law. But this is as much as to say that the principle is not proved by experience, but that experience is understood in the light of the principle. Here, again, empiricism fails us. As in the case of our judgments about particular matters of fact, so also in the case of these other judgments, whose scope is co-extensive with the whole realm of Nature, we find that any endeavour to formulate a rational justification for them based on experience alone breaks down, and, to all appearance, breaks down hopelessly.

VIII But even if this reasoning be sound, may the reader exclaim, What is it that we gain by it? What harvest are we likely to reap from such broadcast sowing of scepticism as this? What does it profit us to show that a great many truths which everybody believes, and which no abstract speculations will induce us to doubt, are still waiting for a philosophic proof? Fair questions, it must be admitted; questions, nevertheless, to which I must reserve my full answer until a later stage of our inquiry. Yet even now something may be said, by way of conclusion to this chapter, on the relation which these criticisms bear to the scheme of thought whose practical consequences we traced out in the first part of these Notes.

I begin by admitting that the criticisms themselves are, from the nature of the case, incomplete. They contain but the concise and even meagre outline of an argument which is itself but a portion only of the whole case. For want of space, or to avoid unsuitable technicalities, much has been omitted which would have been relevant to the issues raised, and have still further strengthened the position which has been taken up. Yet, though more might have been said, what has been said is, in my opinion, sufficient; and I shall, therefore, not scruple henceforth to assume that a purely empirical theory of things, a philosophy which depends for its premises in the last resort upon the particulars revealed to us in perceptive experience alone, is one that cannot rationally be accepted. Is this conclusion, then, adverse to Naturalism? And, if so, must it not tell with equal force against Science, seeing that it is solely against that part of the naturalistic teaching which is taken over bodily from Science that it appears to be directed? Of these two questions, I answer the first in the affirmative, the second in the negative. Doubtless, if empiricism be shattered, it must drag down naturalism in its fall; for, after all, naturalism is nothing more than the assertion that empirical methods are valid, and that no others are so. But because any effectual criticism of empiricism is the destruction of naturalism, is it therefore the destruction of science also? Surely not. The adherent of naturalism is an empiricist from necessity; the man of science, if he be an empiricist, is so only from choice. The latter may, if he please, have no philosophy at all, or he may have a different one. He is not obliged, any more than other men, to justify his conclusions by an appeal to first principles; still less is he obliged to take his first principles from so poor a creed as the one we have been discussing. Science preceded the theory of science, and is independent of it. Science preceded naturalism, and will survive it. Though the convictions involved in our practical conception of the universe are not beyond the reach of theoretic doubts, though we habitually stake our all upon assumptions which we never attempt to justify, and which we could not justify it we would, yet is our scientific certitude unshaken; and if we still strive after some solution of our sceptical difficulties, it is because this is necessary for the satisfaction of an intellectual ideal, not because it is required to fortify our confidence either in the familiar teachings of experience or in their ntmost scientific expansion. And hence arises my principal complaint against naturalism. With Empirical philosophy, considered as a tentative contribution to the theory of science, I have no desire to pick a quarrel. That it should fail is nothing. Other philosophies have failed. Such is, after all, the common lot. That it should have been contrived to justify conclusions already accepted is, if a fault at all which I doubt at least a most venial one, and one, moreover, which it has committed in the best of philosophic company. That it should derive some moderate degree of imputed credit from the universal acceptance of the scientific beliefs which it countersigns, may be borne with, though for the real interests of speculative inquiry this has been, I think, a misfortune. But that it should develop into naturalism, and then, on the strength of labours which it has not endured, of victories which it has not won, and of scientific triumphs in which it has no right to share, presume, in despite of its speculative insufficiency, to dictate terms of surrender to every other system of belief, is altogether intolerable. Who would pay the slight,est attention to naturalism if it did not force itself into the retinue of science, assume her livery, and claim, as a kind of poor relation, in some sort to represent her authority and to speak with her voice? Of itself it is nothing. It neither ministers to the needs of mankind, nor does it satisfy their reason. And if, in spite of this, its influence has increased, is increasing, and as yet shows no signs of diminution; if more and more the educated and the half-educated are acquiescing in its pretensions and, however reluctantly, submitting to its domination, this is, at least in part, because they have not learned to distinguish between the practical and inevitable claims which experience has on their allegiance, and the speculative but quite illusory title by which the empirical school have endeavoured to associate naturalism and science in a kind of joint supremacy over the thoughts and consciences of mankind.