Descartes was the first to begin a system of philosophy with universal doubt, intended to be only provisional and methodical; but his mind was not plastic nor mystical enough to be profoundly sceptical, even histrionically. He could doubt any particular fact easily, with the shrewdness of a man of science who was also a man of the world; but this doubt was only a more penetrating use of intelligence, a sense that the alleged fact might be explained away. Descartes could not lend himself to the disintegration of reason, and never doubted his principles of explanation. For instance, in order to raise a doubt about the applicability of mathematics to existence (for their place in the realm of essence would remain the same in any case) he suggested that a malign demon might have been the adequate cause of our inability to doubt that science. He thus assumed the principle of sufficient reason, a principle for which there is no reason at all. If any idea or axiom were really a priori or spontaneous in the human mind, it would be infinitely improbable that it should apply to the facts of nature. Every genius, in this respect, is his own malign demon. Nor was this the worst; for Descartes was not content to assume that reason governs the world—a notion scandalously contrary to fact, and at bottom contrary to reason itself, which is but the grammar of human discourse and aspiration linking mere essences. He set accidental limits to his scepticism even about facts. “I think, therefore I am,” if taken as an inference is sound because analytical, only repeating in the conclusion, for the sake of emphasis, something assumed in the premise. If taken as an attestation of fact, as I suppose it was meant, it is honest and richly indicative, all its terms being heavy with empirical connotations. What is “thinking,” what is “I,” what is “therefore,” and what is “existence”? If there were no existence there would certainly be no persons and no thinking, and it may be doubted (as I have indicated above) that anything exists at all. That any being exists that may be called “I,” so that I am not a mere essence, is a thousand times more doubtful, and is often denied by the keenest wits. The persuasion that in saying “I am” I have reached an indubitable fact, can only excite a smile in the genuine sceptic. No fact is self-evident; and what sort of fact is this “I,” and in what sense do I “exist”? Existence does not belong to a mere datum, nor am I a datum to myself; I am a somewhat remote and extremely obscure object of belief. Doubtless what I mean by myself is an existence and even a substance; but the rudimentary phantoms that suggest that object, or that suggest the existence of anything, need to be trusted and followed out by a laborious empirical exploration, before I can make out at all what they signify. Variation alleged, strain endured, persistence assumed—notions which when taken on faith lead to the assertion of existence and of substance, if they remained merely notions would prove nothing, disclose nothing, and assert nothing. Yet such, I suppose, are the notions actually before me when I say “I am.” As to myself, when I proceed to distinguish that object in the midst of the moving world, I am roughly my body, or more accurately, its living centre, master of its organs and seat of its passions; and this inner life of the body, I suspect, was the rock of vulgar belief which Descartes found at hand, easy to mount on, after his not very serious shipwreck. And the rock was well chosen; not because the existence of my inner man is a simpler or a surer fact than any other; to a true sceptic this alleged being so busily thinking and willing and fuming within my body is but a strange feature in the fantastic world that appears for the moment. Yet the choice of the inner man as the one certain existence was a happy one, because this sense of life within me is more constant than other perceptions, and not wholly to be shaken off except in profound contemplation or in some strange forms of madness. It was a suitable first postulate for the romantic psychologist. On this stepping-stone to idealism the father of modern philosophy, like another Columbus, set his foot with elegance. His new world, however, would be but an unexplored islet in the world of the ancients if all he discovered was himself thinking.

Thinking is another name for discourse; and perhaps Descartes, in noting his own existence, was really less interested in the substance of himself, or in the fact that he was alive, than in the play of terms in discourse, which seemed to him obvious. Discourse truly involves spirit, with its intuition and intent, surveying those terms. And the definition of the soul, that its essence is to think, being a definition of spirit and not of a man’s self, supports this interpretation. But discourse, no less than the existence of a self, needs to be posited, and the readiness with which a philosopher may do so yields only a candid confession of personal credulity, not the proof of anything. The assumption that spirit discoursing exists, and is more evident than any other existence, leads by a slightly different path to the same conclusion as the assumption of the self as the fundamental fact. In the one case discourse will soon swallow up all existence, and in the other this chosen existence, myself, will evaporate into discourse: but it will remain an insoluble problem whether I am a transcendental spirit, not a substance, holding the whole imaginary universe in the frame of my thought, or whether I am an instance of thinking, a phase of that flux of sentience which will then be the substance of the world. It is only if we interpret and develop the Cartesian axiom in the former transcendental sense that it supplies an instrument for criticism. Understood in an empirical way, as the confident indication of a particular fact, it is merely a chance dogma, betraying the psychological bias of reflection in modern man, and suggesting a fantastic theory of the universe, conveniently called psychologism; a theory which fuses the two disparate substances posited by Descartes, and maintains that while the inner essence of substance everywhere is to think, or at least to feel, its distribution, movement, and aspect, seen from without, are those of matter.

In adopting the method of Descartes, I have sought to carry it further, suspending all conventional categories as well as all conventional beliefs; so that not only the material world but all facts and all existences have lost their status, and become simply the themes or topics which intrinsically they are. Neither myself nor pure spirit is at all more real in that realm of essence than any other mentionable thing. When it comes to assertion (which is belief) I follow Descartes in choosing discourse and (as an implication of discourse) my substantial existence as the objects of faith least open to reasonable doubt; not because they are the first objects asserted, nor because intrinsically they lend themselves to existence better than anything else, but simply because in taking note of anything whatever I find that I am assuming the validity of primary memory; in other words, that the method and the fact of observation are adventitious to the theme. But the fact that observation is involved in observing anything does not imply that observation is the only observed fact: yet in this gross sophism and insincerity the rest of psychologism is entangled.

Hume and Kant seemed sceptics in their day and were certainly great enemies of common sense, not through any perversity of temper (for both were men of wise judgement) but through sophistical scruples and criticism halting at unfortunate places. They disintegrated belief on particular points of scholastic philosophy, which was but common sense applied to revelation; and they made no attempt to build on the foundations so laid bare, but rather to comfort themselves with the assurance that what survived was practically sufficient, and far simpler, sounder, and purer than what they had demolished. After the manner of the eighteenth century, they felt that convention was a burden and an imposture, not because here and there it misinterpreted nature, but because it interpreted or defined nature at all; and in their criticism they ran for a fall. They had nothing to offer in the place of what they criticised, except the same cheque dishonoured. All their philosophy, where it was not simply a collapse into living without philosophy, was retrenchment; and they retrenched in that hand-to-mouth fashion which Protestantism had introduced and which liberalism was to follow. They never touched bottom, and nothing could be more gratuitous or more helpless than their residual dogmas. These consisted in making metaphysics out of literary psychology; not seeing that the discourse or experience to which they appealed was a social convention, roughly dramatising those very facts of the material world, and of animal life in it, which their criticism had denied.

Hume seems to have assumed that every perception perceived itself. He assumed further that these perceptions lay in time and formed certain sequences. Why a given perception belonged to one sequence rather than to another, and why all simultaneous perceptions were not in the same mind, he never considered; the questions were unanswerable, so long as he ignored or denied the existence of bodies. He asserted also that these perceptions were repeated, and that the repetitions were always fainter than the originals—two groundless assertions, unless the transitive force of memory is admitted, and impressions are distinguished from ideas externally, by calling an intuition an impression when caused by a present object, visible to a third person, and calling it an idea when not so caused. Furthermore, he invoked an alleged habit of perceptions always to follow one another in the same order—something flatly contrary to fact; but the notion was made plausible by confusion with the habits of the physical world, where similar events recur when the conditions are similar. Intuitions no doubt follow the same routine; but the conditions for an intuition are not the previous intuitions, but the whole present state of the psyche and of the environment, something of which the previous intuitions were at best prophetic symptoms, symptoms often falsified by the event.

All these haltings and incoherences arose in the attempt to conceive experience divorced from its physical ground and from its natural objects, as a dream going on in vacuo. So artificial an abstraction, however, is hard to maintain consistently, and Hume, by a happy exercise of worldly wit, often described the workings of the mind as our social imagination leads us all vaguely to conceive them. In these inspired moments he made those acute analyses of our notions of material things, of the soul, and of cause, which have given him his name as a sceptic. These analyses are bits of plausible literary psychology, essays on the origin of common sense. They are not accounts of what the notions analysed mean, much less scientific judgements of their truth. They are supposed, however, by Hume and by the whole modern school of idealists, to destroy both the meaning of these notions and the existence of their intended objects. Having explained how, perhaps, early man, or a hypothetical infant, might have reached his first glimmerings of knowledge that material things exist, or souls, or causes, we are supposed to have proved that no causes, no souls, and no material things can exist at all. We are not allowed to ask how, in that case, we have any evidence for the existence of early man, or of the hypothetical infant, or of any general characteristics of the human mind, and its tendencies to feign. The world of literature is sacred to these bookish minds; only the world of nature and science arouses their suspicion and their dislike. They think that “experience,” with the habits of thought and language prevalent in all nations, from Adam down, needs only to be imagined in order to be known truly. All but this imagined experience seems to them the work of imagination. While their method of criticism ought evidently to establish not merely solipsism, but a sort of solipsism of the present datum, yet they never stop to doubt the whole comedy of human intercourse, just as the most uncritical instinct and the most fanciful history represent it to be. How can such a mass of ill-attested and boldly dogmatic assumptions fail to make the critics of science uncomfortable in their own house? Is it because the criticism of dogma in physics, without this dogma in psychology, could never so much as begin? Is not their criticism at bottom a work of edification or of malice, not of philosophic sincerity, so that they reject the claim to knowledge only in respect to certain physical, metaphysical, or religious objects which the modern mind has become suspicious of, and hopes to feel freer without? Meantime, they keep their conventional social assumptions without a qualm, because they need them to justify their moral precepts and to lend a false air of adequacy to their view of the world. Thus we are invited to believe that our notions of material things do not mean what they assert, but being illusions in their deliverance, really signify only the series of perceptions that have preceded them, or that, for some unfathomable reason, may be expected to ensue.

All this is sheer sophistry, and limping scepticism. Certainly the vulgar notions of nature, and even the scientific ones, are most questionable; and they may have grown up in the way these critics suggest; in any case they have grown up humanly. But they are not mere images; they are beliefs; and the truth of beliefs hangs on what they assert, not on their origin. The question is whether such an object as they describe lies in fact in the quarter where they assert it to lie; the genealogy of these assertions in the mind of the believer, though interesting, is irrelevant. It is for science and further investigation of the object to pronounce on the truth of any belief. It will remain a mere belief to the end, no matter how much corroborated and corrected; but the fact that it is a belief, far from proving that it must be false, renders it possibly true, as it could not be if it asserted nothing and had no object beyond itself which it pointed to and professed to describe. This whole school criticises knowledge, not by extending knowledge and testing it further, but by reviewing it maliciously, on the tacit assumption that knowledge is impossible. But in that case this review of knowledge and all this shrewd psychology are themselves worthless; and we are reduced, as Hume was in his deeper moments of insight, to a speechless wonder. So that whilst all the animals trust their senses and live, philosophy would persuade man alone not to trust them and, if he was consistent, to stop living.

This tragic conclusion might not have daunted a true philosopher, if like the Indians he had reached it by a massive moral experience rather than by incidental sophistries with no hold on the spirit. In that case the impossibility of knowledge would have seemed but one illustration of the vanity of life in general. That all is vanity was a theme sometimes developed by Christian preachers, and even in some late books of the Bible, with special reservations; but it is an insight contrary to Hebraic religion, which invokes supernatural or moral agencies only in the hope of securing earthly life and prosperity for ever. The wisdom demanded could, therefore, not be negative or merely liberating; and scepticism in Christian climes has always seemed demoralising. When it forced itself on the reluctant mind, people either dismissed it as a game not worth playing and sank back, like Hume, into common sense, though now with a bad conscience; or else they sought some subterfuge or equivocation by which knowledge, acknowledged to be worthless, was nevertheless officially countersigned and passed as legal tender, so that the earnest practice of orthodoxy, religious or worldly, or both at once, might go on without a qualm. Evidently, to secure this result, it was necessary to set up some oracle, independent of natural knowledge, that should represent some deeper reality than natural knowledge could profess to reach; and it was necessary that this oracle itself, by a pious or a wilful oversight, should escape criticism; for otherwise all was lost. It escaped criticism by virtue of the dramatic illusion which always fills the sails of argument, and renders the passing conviction the indignant voice of omniscience and justice. The principle invoked in criticism, whatever it might be, could not be criticised. It did not need to be defended: its credentials were the havoc it wrought among more explicit conventions. And yet, by a mocking fatality, those discredited conventions had to be maintained in practice, since they are inevitable for mankind, and the basis, even by their weaknesses, of the appeal to that higher principle which, in theory, was to revise and reject them. This higher principle was no alternative view of the world, no revelation of further facts or destinies; it was the thinking or dreaming spirit that posited those necessary conventions, and would itself die if it ceased to posit them. In discrediting the fictions of spirit we must, therefore, beware of suspending them. We are not asked to abolish our conception of the natural world, nor even, in our daily life, to cease to believe in it; we are to be idealists only north-north-west, or transcendentally; when the wind is southerly, we are to remain realists. The pronouncements of animal faith have no doubt been reversed in a higher court, but with this singular proviso, that the police and the executioner, while reverently acknowledging the authority of the higher tribunal, must unflinchingly carry out the original sentence passed by the lower. This escape from scepticism by ambiguity, and by introducing only cancelled dogmas, was chosen by German philosophy at the beginning of the nineteenth century, and by modernism and pragmatism at the end of it.

Kant was thought a sceptic in his day, and called his philosophy criticism; but his scepticism was very impure and his criticism, though laborious, was very uncritical. That he was regarded as a great philosopher in the nineteenth century is due to the same causes that made Locke seem a great philosopher in the eighteenth, not to any intrinsic greatness. He announced some revolutionary principles, which alarmed and excited the public, but he did not carry them out, so that the public was reassured. In his criticism of knowledge he assumed without question the Humian sequences of perceptions, although contrary to his doctrine of time; and, more wisely than Hume, he never abandoned the general sense that these perceptions had organs and objects beneath and beyond them; but having cut off, by his malicious criticism of knowledge, the organs and objects which perceptions notoriously have, he was forced to forge others, artificial and metaphysical. Instead of the body, he posited a transcendental ego, the categories of thought, and a disembodied law of duty; instead of natural substances he posited the unknowable. I shall revert to these subjects in discussing the realm of matter, which is where they belong. Here I am concerned only with the analysis of knowledge, which in Kant was most conscientious, and valuable in spite of its rationalistic bias and its mythical solutions.

Any intelligent mind comes upon data and takes them for signs of things. Empirical criticism consists in reverting from these objects of intent, the things of common sense and science, to the immediate data by which they are revealed. But since data are not vacantly stared at by an intelligent being, but are interpreted and combined, there is evidently a subtler element in knowledge of things than the data which empirical criticism reverts to: namely, the principles of interpretation, since the data are read and taken to be significant of existing objects, far richer and more persistent and more powerful than themselves. These principles I have summarily called animal faith, not being concerned to propose any analysis of them that should apply to all minds or to all objects; for I conceive, for instance, that the future, in other animals, may be a more frequent and vivid object of animal faith than the past or the material environment posited by human beings. But Kant, assuming that mind everywhere must have a single grammar, investigated very ingeniously what he conceived to be its recondite categories, and schemata, and forms of intuition: all pompous titles for what Hume had satirically called tendencies to feign. But Kant, in dishonouring the intellect, at least studied it devotedly, like an alienist discovering the logic of madness; and he gave it so elaborate an articulation, and imposed it so rigorously on all men for ever, that people supposed he was establishing the sciences on a solid foundation rather than prescribing for all men a gratuitous uniformity in error. Yet this was his true meaning: and in spite of its psychological prefaces and metaphysical epilogues, and in spite of this pedantry about the necessary forms of all the sciences, the heart of the Kantian system was the most terrible negation. Among transcendental principles he placed space, time, and causality; so that, if he had been consistent, he would have had to regard all multiple and successive existence as imagined only. Everything conceivable would have collapsed into the act of conceiving it, and this act itself would have lost its terms and its purpose, and evaporated into nothing. But not at all; as if aware that all his conclusions were but curiosities in speculation and academic humours, he continued to think of experience as progressing in time, trifled most earnestly with astronomy and geography, and even comforted the pious with a postulate of immortality, as if time existed otherwise than in imagination. In fact, these backslidings were his amiable side: he always retained a certain humanity and wisdom, being much more thoroughly saturated with his conventional presuppositions than with his extravagant conclusions.

A philosopher, however, must be taken at his best, or at his worst; in any case, his pure doctrine must be freed as far as possible from its personal alloy: and the pure doctrine of Kant was that knowledge is impossible. Anything I could perceive or think was ipso facto a creature of my sense or thought. Nature, history, God and the other world, even a man’s outspread experience, could be things imagined only. Thought—for it was still assumed that there was thought—was a bubble, self-inflated at every moment, in an infinite void. All else was imaginary; no world could be anything but the iridescence of that empty sphere. And this transcendental thought, so rich in false perspectives, could it be said to exist anywhere, or at any time, or for any reason?

Here we touch one of those ambiguities and mystifications in which German philosophy takes refuge when pressed; strong in the attack, it dissolves if driven to the defensive. Transcendentalism, in so far as it is critical, is a method only; the principles by which data are interpreted come into play whenever intelligence is at work. The occasions for this exercise, as a matter of fact, are found in animal life; and while every mind, at every moment, is the seat and measure of its own understanding, and creates its own knowledge (though, of course, not the objects on which animal life is directed and which it professes to know) yet the quality and degree of this intelligence may vary indefinitely from age to age and from animal to animal. Transcendental principles are accordingly only principles of local perspective, the grammar of fancy in this or that natural being quickened to imagination, and striving to understand what it endures and to utter what it deeply wills. The study of transcendental logic ought, therefore, to be one of the most humane, tender, tentative of studies: nothing but sympathetic poetry and insight into the hang and rhythm of various thoughts. It should be the finer part of literary psychology. But such is not the transcendentalism of the absolute transcendentalists. For them the grammar of thought is single and compulsory. It is the method of the creative fiat by which not this or that idea of the universe, but the universe itself, comes into being. The universe has only a specious existence; and the method by which specious existence is evoked in thought is divine and identical in all thinking.

But why divine, and why always identical? And why any thinking at all, or any process or variation in discourse, other than the given perspectives of the present vision? At this point vertigo seizes the transcendentalist, and he no longer knows what he means. On the one hand, phenomena cannot be produced by an agency prior to them, for his first principle is that all existence is phenomenal and exists only in being posited or discovered. Will, Life, Duty, or whatever he calls this transcendental agency, by which the illusions of nature and history are summoned from the vasty deep, cannot be a fact, since all facts are created by its incantations. On the other hand phenomena cannot be substantial on their own account, for then they would not be phenomena but things, and no transcendental magician, himself non-existent and non-phenomenal, would be needed to produce them.

Absolute transcendentalism—the only radical form of a psychological criticism of knowledge—is accordingly not a thinkable nor a stable doctrine. It is merely a habit of speaking ambiguously, with a just sense for the living movement of thought and a romantic contempt for its deliverance. Self-consciousness cannot be, as this school strove to make it, a first principle of criticism: it is far too complex and derivative for that. But transcendentalism is a legitimate attitude for a poet in his dramatic reflections and romantic soliloquies; it is the principle of perspective in thought, the scenic art of the mental theatre. The fully awakened soul, looking about it in this strange world, may well believe that it is dreaming. It may review its shifting memories, with a doubt whether they were ever anything in themselves. It may marshal all things in ideal perspectives about the present moment, and esteem them important and even real only in so far as they diversify the mental landscape. And to compensate it for the visionary character which the world takes on, it may cultivate the sense (by no means illusory) of some deep fountain of feeling and fancy within the self. Such wistful transcendentalism is akin to principles which in India long ago inspired very deep judgements upon life. It may be practised at will by any reflective person who is minded to treat the universe, for the time being, as so much furniture for his dreams.

Yet this attitude, seeing that man is not a solitary god but an animal in a material and social world, must be continually abandoned. It must be abandoned precisely when a man does or thinks anything important. Its own profundity is dreamful, and, so to speak, digestive: action, virtue, and wisdom sound another note. It is therefore no worthy philosophy; and in fact the Germans, whose philosophy it is, while so dutiful in their external discipline, are sentimental and immoral in their spiritual economy. If a learned and placid professor tells me he is creating the universe by positing it in his own mind according to eternal principles of logic and duty, I may smile and admire such an inimitable mixture of enthusiasm and pedantry, profundity and innocence. Yet there is something sinister in this transcendentalism, apparently so pure and blameless; it really expresses and sanctions the absoluteness of a barbarous soul, stubborn in its illusions, vulgar in its passions, and cruel in its zeal—cruel especially to itself, as barbarism always is, because it feeds and dilates its will as if its will were an absolute power, whereas it is nothing but a mass of foolish impulses and boasts ending in ignominy. Moreover, transcendentalism cannot even supply a thorough criticism of knowledge, which would demand that the ideas of self, of activity, and of consciousness should be disintegrated and reduced to the immediate. In the immediate, however, there is no transcendental force nor transcendental machinery, not even a set of perceptions nor an experience, but only some random essence, staring and groundless.

I hope I have taken to heart what the schools of Hume and Kant have to offer by way of disintegrating criticism of knowledge, and that in positing afresh the notions of substance, soul, nature, and discourse, I have done so with my eyes open. These notions are all subject to doubt; but so, also, are the notions proposed instead by psychological philosophers. None of these have reached the limit of possible doubt; yet the dogmas they have retained, being romantic prejudices, are incoherent and incapable of serving as the basis for any reasonable system: and in a moral sense they are the very opposite of philosophy. When pressed, their negations end in solipsism and their affirmations in rhapsody. Far from purging the mind and strengthening it, that it might gain a clearer and more stable vision of the world, these critics have bewildered it with a multitude of methods and vistas, the expression of the confusion reigning in their day between natural science and religious faith, and between psychology and scepticism.

My endeavour has been to restore these things to their natural places, without forgetting the assumptions on which they rest. But the chief difference between my criticism of knowledge and theirs lies in the conception of knowledge itself. The Germans call knowledge Wissenschaft, as if it were something to be found in books, a catalogue of information, and an encyclopædia of the sciences. But the question is whether all this Wissenschaft is knowledge or only learning. My criticism is criticism of myself: I am talking of what I believe in my active moments, as a living animal, when I am really believing something: for when I am reading books belief in me is at its lowest ebb; and I lend myself to the suasion of eloquence with the same pleasure (when the book is well written) whether it be the Arabian Nights or the latest philosophy. My criticism is not essentially a learned pursuit, though habit may sometimes make my language scholastic; it is not a choice between artificial theories; it is the discipline of my daily thoughts and the account I actually give to myself from moment to moment of my own being and of the world around me. I should be ashamed to countenance opinions which, when not arguing, I did not believe. It would seem to me dishonest and cowardly to militate under other colours than those under which I live. Merely learned views are not philosophy; and therefore no modern writer is altogether a philosopher in my eyes, except Spinoza; and the critics of knowledge in particular seem to me as feeble morally as they are technically.

I should like, therefore, to turn to the ancients and breathe again a clear atmosphere of frankness and honour; but in the present business they are not very helpful. The Indians were poets and mystics; and while they could easily throw off the conventions of vulgar reason, it was often only to surrender themselves to other conventions, far more misleading to a free spirit, such as the doctrine of transmigration of souls; and when, as in Buddhism, they almost vanquished that illusion, together with every other, their emasculated intellect had nothing to put in its place. The Greeks on the contrary were rhetoricians; they seldom or never reverted to the immediate for a foothold in thought, because the immediate lies below the level of language and of political convention. But they were disputatious, and in that sense no opinion escaped their criticism. In this criticism they simply pitted one plausible opinion against another, supporting each in turn by all conceivable arguments, based on no matter what prejudices or presumptions. The result of this forensic method was naturally a suspense of rational judgement, favourable now to frivolity and now to superstition. The frivolity appeared in the Sophists who, seeing that nothing was certain, impudently assumed as true whatever it was socially convenient to advocate. Protagoras seems to have reduced this bad habit to an honest system, when he taught that each occasion is, for itself, the ultimate judge of truth. This, taken psychologically, is evidently the case: a mind cannot judge on other subjects nor on other evidences than are open to it when judging. But the judging moment need not judge truly; and to maintain (as Protagoras does in Plato’s Dialogue and as some pragmatists have done in our day) that all momentary opinions are equal in truth, though not equal in value, is to fail in radical scepticism: for it is to assume many moments, and knowledge (utterly inexplicable on these principles) of their several sequences and import; and to assume something even more wanton, a single standard of value by which to judge them all. Such incoherence is not surprising in sophists whose avowed purpose in philosophising is to survive and succeed in this world, or perhaps in the next. Worldly people will readily admit that some ideas are better than others, even if both sets are equally false. The interest in truth for its own sake is not a worldly interest, but the human soul is capable of it; and there might be spirits directed on the knowledge of truth as upon their only ultimate good, as there might be spirits addressed exclusively to music. Which arts and sciences are worth pursuing, and how far, is a question for the moralist, to be answered in each case in view of the faculties and genius of the persons concerned, and their opportunities. Socrates may humorously eschew all science that is useless to cobblers; he thereby expresses his plebeian hard sense, and his Hellenic joy in discourse and in moral apologues; but if he allows this pleasant prejudice to blind him to the possibility of physical discoveries, or of cogent mathematics, he becomes a simple sophist. The moralist needs true knowledge of nature—even a little astronomy—in order to practise the art of life in a becoming spirit; and an agnosticism which was not merely personal, provisional, and humble would be the worst of dogmas.

A sinking society, with its chaos of miscellaneous opinions, touches the bottom of scepticism in this sense, that it leaves no opinion unchallenged. But as a complete suspense of judgement is physically impossible in a living animal, every sceptic of the decadence has to accept some opinion or other. Which opinions he accepts, will depend on his personal character or his casual associations. His philosophy therefore deserts him at the threshold of life, just when it might cease to be a verbal accomplishment; in other words, he is at intervals a sophist, but at no time a philosopher. Nevertheless, among the Greek sceptics there were noble minds. They turned their scepticism into an expression of personal dignity and an argument for detachment. In such scepticism every one who practises philosophy must imitate them; for why should I pledge myself absolutely to what in fact is not certain? Physics and theology, to which most philosophies are confined, are dubious in their first principles: which is not to say that nothing in them is credible. If we assert that one thing is more probable than another, as did the sceptics of the Academy, we have adopted a definite belief, we profess to have some hold on the nature of things at large, a law seems to us to rule events, and the lust of scepticism in us is chastened. This belief in nature, with a little experience and good sense to fill in the picture, is almost enough by way of belief. Nor can a man honestly believe less. An active mind never really loses the conviction that it is scenting the way of the world.

Living when human faith is again in a state of dissolution, I have imitated the Greek sceptics in calling doubtful everything that, in spite of common sense, any one can possibly doubt. But since life and even discussion forces me to break away from a complete scepticism, I have determined not to do so surreptitiously nor at random, ignominiously taking cover now behind one prejudice and now behind another. Instead, I have frankly taken nature by the hand, accepting as a rule in my farthest speculations the animal faith I live by from day to day. There are many opinions which, though questionable, are inevitable to a thought attentive to appearance, and honestly expressive of action. These natural opinions are not miscellaneous, such as those which the Sophists embraced in disputation. They are superposed in a biological order, the stratification of the life of reason. In rising out of passive intuition, I pass, by a vital constitutional necessity, to belief in discourse, in experience, in substance, in truth, and in spirit. All these objects may conceivably be illusory. Belief in them, however, is not grounded on a prior probability, but all judgements of probability are grounded on them. They express a rational instinct or instinctive reason, the waxing faith of an animal living in a world which he can observe and sometimes remodel.

This natural faith opens to me various Realms of Being, having very different kinds of reality in themselves and a different status in respect to my knowledge of them. I hope soon to invite the friendly reader to accompany me in a further excursion through those tempting fields.