page 54

Professor M'Gregor's Introductory Lecture.

Mr. Vice-Chancellor, Ladies and Gentlemen—

Of the departments of Science to be studied in our University the Mental Sciences have been committed to me. It naturally falls to me, therefore, in my opening lecture, to survey the extent and redd the marches of my subject. To do this is especially necessary in the circumstances in which we at present find ourselves, assembled as we are to open a class for the study of a science whose scope and method are now becoming very different from what they used to be. Looking at the present state of science, it cannot fail to strike us that those sciences are most advanced whose subject-matter is least complicated. Quantity and number, the subject-matter of Mathematics, hold true of all things in all time, and are clear and uncomplicated as our ideas of space and time on which they rest. Masses of matter in motion, the subject-matter of Astronomy, stands next in point of simplicity. Hence Mathematics and Astronomy are pre-eminently the exact sciences, simply because they are least dependent on any others, and are not, before they advance, compelled to tarry for their lagging sisters. Far otherwise is the case, for instance, with Medicine, whose phenomena, before they can be reduced to law, or any attempt made at such-reduction, must be studied by the light of principles made known by the previous labours of chemists and physicists, and applied to the study of the human body and the functions of its organs. After thus learning all that is known to anatomists and physiologists of the structure and functions of the body in health, Pathology must be studied to find what changes are wrought by disease; and Therapeutics, to find the means of prevention and cure. Here also comes into play an urgent desire for knowledge as a means of avoiding misery, which, though a great motive for study, is at the same time a disturbing force of enormous potency, and hinders, by the excitement and eagerness that it engenders, the attainment of the object it desires. If the difficulties of Medicine be so great, and its dependence on other sciences so complete, what wonder that, when to the enormous complexities of man's bodily frame are superadded the still greater complexities of his mental constitution, the difficulties should be the greatest within the whole range of human study and page 55 progress, most slow and laborious. Add to all this that mans eagerness to understand his own nature, origin, and destiny, is little if at all less absorbing than his desire for the cure and alleviation of his bodily ailments, and becomes immeasurably greater as he grows in understanding and intelligence. There is yet another obstacle here to progress greater than any other: that is, the blinding power of the feelings which, in all ages, have, biassed men where their loves, their hatreds, their selfish interests, or their religious sentiments, are involved. Liking inclines us to believe all the good we can of its object, and is a motive power for belief able to surmount almost any degree of opposing proof. The lawyer is loath to move in reforming a process that pays well, and even priests of the most High have been found to justify the enslaving of their fellow-men.

No practice is too odious, no error too gross, to be vindicated and made praiseworthy by those who are well paid for doing so. Our fears also do much to hinder our reception of the truth. For instance, with regard to a future state, man's actions may, and often do, make it his interest to disbelieve in it, and he straightway contrives to do so. Our bodily health also, as influencing our mental elasticity, is not without its influence. Where we know nothing, elated we place Hope; depressed we place Terror. From this root arising, superstition now keeps many, and for ages kept all, in the bondage of ignorance. In the view of this increasing complexity and concomitant implication of our feelings and strong emotions, all helping to obscure the truth, what wonder is it that mathematicians and astronomers agree, while philosophers and doctors differ? It is nothing strange then, seeing man's strongest feelings are involved, and his future destiny staked on the conclusion he comes to regarding his own nature and his duties, that the history of this subject should be such as it is—that for ages the noblest intellects of our race, ignorant of the knowledge which we have inherited, and thus having no matter to their thought, but only words which they mistook for things, should have enunciated system after system of metaphysical thought; each of which, in its turn, professed to solve the problems of man's nature, and to have grasped at length the secret of the universe. For many ages this intensely natural but fatally unscientific impulse drove men to seek truth by all methods but that by which alone she is to be found; namely, the patient and laborious observation of nature, in order to discover her laws. The philosophers, in their impatience to possess a key wherewith to unlock the arcana of nature, struggled incessantly, but ever in vain, to find entrance by forbidden and impossible ways. In the absence of scientific inductions whereon to build, they built on the sand, and with the returning tide their structures perished.

In the "haunt obscure of old philosophy," as if in the gloomy depths of some labyrinthine cavern, the thoughtful of all ages page 56 continued to grope blindly their way ever and anon amid the tortuous sinuosities of their path, finding themselves on the beaten track trodden by thousands of weary seekers before them, none of whom could find an exit to the light, or solve the mystery of existence. In brief, this oldest and noblest of the sciences became a bye-word and a reproach, a synonym for profoundly subtle, trifling, and endless perplexity. Her literature, the more one reads it, reduces to chaotic bewilderment all our ideas and beliefs. It is like sailing over a tempestuous ocean without chart or compass, the sun clouded over by day, and the night without a star. Yet sight the land that lies beyond we must, or prove that it exists not. Our life depends on it, and we cannot choose, but venture.

Is there then no hope of a compass or a pilot? Are we hopelessly tied down to this spec of earth that we inhabit, there to play out our little part and perish? If there is no life beyond the present, no promised land, no haven of rest; to what purpose, I ask, is it that we are endowed with aspirations and faculties, whoso width of sweep serves only to make us miserable, by making the greatest objects of human ambition seem unspeakably contemptible? Why are our faculties so hugely disproportioned to our condition that the inevitable result of their exercise is to make us discontented with our lot? and why are our desires greater even than these faculties can satisfy? Instead of being benevolent, the Creator that made us thus with such powers and such unresting eagerness of desire for we know not what, must have designed to make us miserable, and chafe our lives out against the bars of our prison all the more violently the nobler we are. Not so; we do not perish when our body rots. This want of adaptation to our present surroundings is designed to make us feel that this is not our rest, There is a means of bridging this vast abyss that limits and encloses the faculties of man; not, however, constructed by any science of ours; nor does science any longer pretend to such a power. How far, then, can science legitimately go, and at what point must she give place to religion? This has been the world's great battle-field, the debateable laud of history, where age after age have mingled in interminable strife the cultivators of science and the apologists of religion.

Let us, for the sake of conciseness, transfer our gaze from the wide stage of history, and consider for a moment the epitome of the same great drama that is played out on the narrow stage of an individual life.

In the golden days of youth, before reason demands a scrutiny of all our opinions and beliefs, in order to lay bare their foundations before admitting their validity, our mental attitude is one of spontaneous activity and unquestioning enjoyment. We are blindly trustful in others, and hopeful ever—as we feel now we shall feel always; we judge of others by ourselves, and the present wholly absorbs us. Sooner or later, however, in the life of every page 57 man who awakens to the consciousness of his powers and consequent responsibilities there comes a change. Reason, till now dormant, awakens and asserts its prerogative to doubt till proof is given. Before, he believed too much; he makes up for it now by believing too little. His most cherished convictions are weighed in the balance and sometimes found wanting. Bit by bit his foothold fails him, and he drifts into universal incertitude. This is the critical period in the life of youth: winds are high, all sail set, ballast often wanting, and the steersman unwary,—what wonder then that many make shipwreck of faith and a good conscience?

As in the unreflecting time of youth, so in the unscientific ages of the world—religion was freighted so heavily with ignorance and superstition that she could not have continued to float till now had she not been forced by science, increasingly as knowledge advanced, to heave overboard this lumber which many good men persisted in believing to be an essential part of her cargo. Religion having been thus deeply laden in the past, is necessarily somewhat laden still with what will hereafter be found to be but traditions of men. Always as this heaving overboard becomes no longer avoidable, religious men live in daily dread of what this encroaching science may be at next, and consign to be carried forth to its burial. Each side lives in constant dread of the other, notwithstanding that both equally with single eye are loyal to truth as they see it. Indeed they fight because they are loyal, for each thinks that truth is imperilled by the other.

There remains, however, the indubitable fact, that while science advances by pushing back the boundary line of religion, yet in the very act of advance her own outermost barrier is rising more clearly into view. She begins practically to admit that her scope is limited, that after she has done her utmost she cannot penetrate beyond mere uniformities of succession, which all converge the more clearly as they near their centre into an inscrutable all-pervading Power, from which primordial source emanates the energy that is manifested to us in the unresting flux of nature's phenomena. We find then that the sphere of science has steadily widened by pushing back the frontiers of nescience. The sphere of religion being to man's unaided faculties shrouded in mystery was wrongly, though inevitably, imagined to be co-extensive with the ever lessening nescience of the time. Science thus was robbed of the room given her to grow in. She has grown, and must continue to grow, at the expense of nescience. She seems to grow at the expense of religion, because we at any rate, if nature does not, abhor a vacuum, and accordingly fill up the hiatus between the true boundary of religion and the extremest outposts of our actual science by stretching our religion to cover our nescience. It is only, however, so long as we confine our regard to mere superficial extent, so to speak, that there is even page 58 seeming antagonism and encroachment by the one on the sphere of the other. Science seems to compel religion into ever narrowing limits by forming into classes, bringing under laws, making natural, phenomena that were formerly isolated, unexplained, super-natural. This is essentially a superficial procedure. Despairing of explanation so long as explanation meant unfolding the nature and origin of things as well as the laws they obey, science, in order to make progress possible, evacuates the word of the former half of its meaning, confines it to the bringing of any fact under a law, and there leaves it. She refuses to entertain a search for causes, and restricts her mission to the discovery of laws.

It is obvious then that science even the profoundest is essentially superficial, for the all-sufficient reason that such is all the science that is possible to us. She takes from religion with the one hand, only to give her more amply and enduringly with the other. Things mysterious, i.e., things isolated, are such no longer; but at the same time things simple are becoming the most mysterious of all. Knowledge advances with equal strides towards the natural and supernatural alike, both being found to be inextricably involved when you get to the bottom of any phenomenon.

Is it true that the causes of this truceless war that has raged between religion and science are to be found wholly on the side of the former? Far otherwise is the fact; for we find that just as religion has often been more irreligious than science, science also has been less scientific than religion. After every decided step in advance, she has had, in periodic paroxysms, fits of unendurable self-sufficiency and conceit, necessitating abundant depletion at the hand of Theology, on which, during such temporary aberrations, she would persist in making the most vehement assaults. Large classes of hitherto unexplained facte are brought under the sweep of some principle of commanding generality. Knowledge is power, and so, in the natural exultation that the grasp of such a principle causes, giving as it does ever increasing mastery over the gigantic powers of nature, we cannot wonder that its discoverers, and still more their disciples, get intoxicated with the consciousness of might. They are impatient to use it as a weapon to demolish the prejudices of the unscientific, all-forgetful that not every man can bend the bow of Ulysses. At present the strife is raging, and for a long time to come will rage around the facts of organization, life, and thought. Meanwhile, the becoming attitude for us is one of keen-eyed yet candid watchfulness. Let our motto be "Magna est Veritas et prevalebit," for it is the true interest of every honest inquirer that, cost what it may, the truth must be known, and, as soon as known, believed. At the same time, be it never forgotten that there lies a profounder meaning than most of us imagine in the trite saying that "a little knowledge is a dangerous thing." It has an intoxicating effect, especially on such as have not had to bear the burden and heat of the day, but, seated at their ease, page 59 gorge without assimilating the results of the thousand toilsome tentatives, abortive experiments, and blind gropings of the discoverer. This knowledge of results, merely without any acquaintance with their genesis, of opinions without the history of their growth and the errors that hindered it, is one of the greatest evils in modern education. This defect is specially pernicious when those moral principles are at stake by which a man has been accustomed to guide his life and rule his conduct. Any new dictum of science, compelling re-examination and modification here, ought to have its claims most rigorously scrutinised. And this, amongst others, is a reason why. The sincerest most single-eyed seeker of truth, so subtle is error, may almost unconsciously welcome a doctrine he otherwise would not, because it promises to loosen the hold of moral restrictions which had already begun to be irksome. If this be so, who can calculate the evil done by a doctrine wholly or partially an error, which counterfeits truth, obtains the sanction of science, and weakens the power of public morality by previously sapping the regulative convictions of individual men.

Granted that soon the counterfeit will be detected, and the fallacy exposed, can its blighting effects be neutralised or even momentarily arrested? The down-hill road is easy, and the velocity increases with the distance.

Moreover it holds true, gainsay it who lists, that purity of life is the sine quâ non of faithful moral perception. The student whose increasing knowledge gives increasing liberty, which imperceptibly degenerates into license, is a self-deceiver, though he may not know it; and he will do well to pause till his vision be purified, and distorting media removed, by casting out the impurities that exhaled them.

The increasing frequency and momentum of the collisions between religion and science is really the beginning of the end. They are due to the fact that the explorers are moving along radii rapidly converging to their common centre, which being reached, or even brought distantly above the horizon, the combatants in this perennial strife will gladly beat their swords into ploughshares and study war no more.

I have thus briefly, and with such clearness as was possible in such narrow compass, touched upon the relations of religion and science, in order to place before you the more intelligibly, what is now a-days meant by Philosophy. In the universe of knowledge science and religion are complementary. With the first rise of intelligence and the consciousness, however dim, of the cosmos emerging from the darkness, religion asserted her sway. Slowly and laboriously through the ages man's perception of the universal order kept growing in clearness, and his religion in intelligence, till at length, after the Greeks had fruitlessly by a prematurely deductive Philosophy toiled to reduce the many to the one, science vindicated for herself a position independent of page 60 Theology. The various sciences, for the purpose of methodical exploration, divided the universe among them. Each had allotted to her some definite department of nature, and concentrated her energies on discovering the laws of her own phenomena, taking no concern with aught beyond save to appropriate and turn to account the discoveries of the rest. Each science is compelled to admit the existence of some Power, and that this Power is and can be known to her only in terms of force; she therefore relegates all further questions to Philosophy. So long as even the most general and profound discoveries are looked at simply as the most fundamental, each of its own science; so long as there is no attempt at a coordination of these principles, and their reduction to one system is ignored, philosophy has no existence as yet, but only science. To quote Spencer: "The truths of Philosophy thus bear the same relation to the highest scientific truths that each of these bears to lower scientific truths. As each widest generalization of science comprehends and consolidates the narrower generalizations of its own divisions, so the generalizations of philosophy comprehend and consolidate the widest generalizations of science. It is therefore a knowledge the extreme opposite in kind to that which experience first accumulates. It is the final product of the process which begins with a mere colligation of crude observations, goes on establishing propositions that are broader and more separated from particular cases, and ends in universal propositions. Or to bring the definition to its simplest and clearest form: knowledge of the lowest kind is ununified knowledge; science is partially unified knowledge; philosophy is completely unified knowledge."

According to this view, while science furnishes the data of Philosophy, philosophy determines the limits of Science, and both equally in so far as they differ from mere speculation are confined to the sphere of the Relative. We are so accustomed to regard the nature and limits of the different sciences as being wholly determined by their objects, that at first we fail to see that the real limiting determining power is the science which teaches us the reach of our faculties—or, in other words, the length of our tether. Astronomy does not consist in the distances, attractions, and motions of the heavenly bodies, but in the knowledge of these acquired by the mental evolution of their laws. From the overwhelming confusion of phenomena, mind evokes the cosmos, as the genius of the sculptor induces over the shapeless marble the shapely lineaments of the statue. Science is not the existence of phenomena obeying laws, but these phenomena observed by mind and classified according to its laws. To the science of mind all the rest are related as to a common centre and substratum grouped concentrically around her in the order of their simplicity, they may be said to form a circle whose circumferential line is occupied by philosophy, inasmuch as it is she that determines the relations of science as a whole to the infinite beyond. The sciences page 61 contribute severally their widest generalizations; she aims at the widest of all the Central Unity; at grasping by the faculties of man the Great First Cause, in whom we live, and move, and have our being.

Formerly, this was thought to form a part of the legitimate business of Philosophy, till, from the failure of their efforts, men learned to narrow the sphere of their search. They vainly attempted a science of Transcendental Metaphysics; they aimed at cognizing the Absolute, forgetful that a God who can be compassed by reason is no longer a God, whom his rational creatures can worship. This conception of Metaphysics (a name commonly restricted to the higher regions of Philosophy) which, to this hour, prevails in Germany, is clearly incompetent. We must restrict her area to the limits set in the very name by its great originator Aristotle, ta met a ta physica, i.e., what comes after or above Physics.

To this over-ambitious philosophy we may aptly reply in the words of Scripture:—"Canst thou by searching find out God? canst thou find out the Almighty to perfection?" Nay, verily, Philosophy is not the means, is not the bridge by which man can span the abyss that intervenes between the universe we see and its invisible Maker and Upholder. He is the self-appointed Goal towards which have agonized unceasingly in every age the excellent of the earth, the noblest of human kind. Some drawn or driven—Which? By the intellectual; others by the moral necessities of their nature. Be this as it may, both equally bring man to the point where, having done his utmost and despairing, he sees most clearly his littleness by the light of his own most transcendent discoveries.

Like an eagle weary of his mighty wings, from the increasing tenuity of the circumambient air, man can soar no higher. At this altitude his grasp of principles, even the clearest, gets weaker; as he rises, they lose their distinctness of outline, are no longer mutually exclusive, and he lands at length in complete imbecility of thought, which here sets its own laws at defiance, and, therefore, is thought no longer.

Contradictions here are equally irresistible, and equally true, simply because man, trying to transcend his own consciousness, gets beyond the limits of true predication. He has no matter to his thought, but only words which he mistakes for things. Consciousness of objects no longer accompanies him in his flight—not because there is no existence there, but because he no longer obeys the conditions of cognizing it.

Here we are face to face with the truth that all knowledge is relative—the profoundest law in the science of mind, and therefore in all sciences whatever. This is the doctrine so ably vindicated by Hamilton against the French and German absolutists, and so clearly expounded by Mansell in his "Lectures on the limits of page 62 Religious Thought." It was the tacit recognition of this law by the physical sciences, at an early stage of their history, that enabled them to make such rapid progress and attain to their present imposing position. It was the non-recognition of the same law by philosophers that rendered their science so barren of abiding results. From a false alarm at its apparent consequences, this law, which science was incessantly urging on the consideration of theologians and students of philosophy, was regarded as a yoke not to be tolerated—the very insignia of bondage. It shewed too clearly the folly of system-making, and the inveterate habit of anticipating nature so easy and seductive to the overvaulting yet indolent intellect of man. The change was, and is, all the harder from the dispiriting contrast that is offered by the grand and elaborate dogmatic structures where philosophy had formerly her abode, to the miserable provisional tenement which she is summoned to content herself with till, by her own genuine and legitimate labour, she is able to plan and build a mansion that shall be eternal. The change is imperative, and no longer avoidable. She must restrict her pretensions to what her data allow, else, by the nemesis of violated law, she must be cast forth as useless—a branch, indeed, of the tree of knowledge, but now only fit for the burning. Shall we, then, despair of her future? Indeed, there is no choice left us in this matter. For every son of man whose desires go beyond the bread that perisheth, and whose brains are competent to think at all, must, consciously or not, be a metaphysician. I hold it a settled point that this science has in it a vitality that is indestructible, in spite of the bewildering prospect which its past and even its present affords. It is founded on an impulse which cannot be kept under, because it originates in an intellectual craving which cannot be repressed. To quote the words of an eminent metaphysician—"To suppose that the light of metaphysics, fitful, or lurid, or bewildering as it may too often be, can ever be extinguished, is to suppose that man has ceased to have a thinking mind. As long as man thinks, this light must burn. The deep river of speculation, with all its devious windings, with all its perilous shoals, whirlpools, and cataracts, will flow on for ever; and he must be a rustic—a barbarian, indeed—who would loiter on its banks in the vain expectation of beholding the mightly flood at length run dry. Let people decry the science as they may, of this we may be assured, that they know it in their secret hearts to be the most essential and the most ethereal manifestation of mental power which the human intellect can exhibit."

What now remains for me to do in the following out of the too extensive plan of this lecture, is to set forth, however meagerly, the bearings of the great modern generalization of the persistance of Force on that branch of our subject called Psychology, or the science of the facts of consciousness. Nature, viewed as a pro- page 63 blem to be solved now-a-days, presents herself under an aspect entirely different from what she used to wear, namely, that of one central force, which, variously modified by various collocations of matter, is the cause of all the change and movement that any-where take place. By some psychologists mental force is regarded with certain limitations as a member of the correlated group into which this central force is modified, and, by consequence, the phenomena of man's mental and moral nature are directly traceable to this source. Let us see how far this is true. If it be not the whole truth our ideas will be all the clearer if we follow them up to see where they bottom, and we shall have clearly defined our frontier: Let us then endeavour to gain a clear understanding of this idea—the keystone in the arch of modern science—with regard to which, as the radiating centre of all force, every physical science must clearly define its position, as must also our science, in so far as it is physical. To the unaided senses all human forces are inappreciable in their minute manifestations, and accordingly were supposed to come to nothing. It is now known that in every case where a force has operated and apparently come to nothing, that there is invariably an effect produced, and that this is due to the force reappearing in a new shape. The question then has come to be—Does the force displayed in every change, from the upheaval of a continent to the movement of a fly on the ceiling, in the very act of being expended, become converted into an equivalent amount of some other force or forces? To this experimental enquiry is giving an affirmative answer with ever increasing distinctness. Motion, being arrested, is actually found under certain circumstances to be changed into heat, chemical force, electricity, magnetism, light, and provisionally nervous force or mind. Taking heat as the most familiar, it is found by experiment to be but a mode of motion. When, for instance, a cannon ball, impinging on a rock is suddenly arrested in its flight, what takes place is simply this—the motion that before impact was molar, i.e., carried along the ball as one mass, has now become molecular, i.e., the atoms composing the ball are set a swinging violently each against the others. In consequence the body expands, the atoms requiring more room to move in, and the feeling of heat is produced. Conversely, heat can be resolved into motion, as is familiarly proved when we see the piston of a steam-engine, with all the concomitant masses of matter, set in motion by the molecular expansion of water into steam. Heat expands the water into vapour to give its particles elbow-room, so to speak; the piston is driven up, and a train of a hundred carriages is hurled along because heat is motion, and nothing more. The same thing may be further illustrated by reflecting that the coal which gave out the heat which generated the steam was dug from the bowels of the earth, where it had Iain for geological ages, all that remain of the vegetation that clothed the primeval world. Coal is nothing more than the carbon that page 64 was stored up in the tissues of plants, after being disengaged by the solar rays. The sun is thus seen to be proximately the prime mover of all things. For, owing to its enormous size, it is still radiating with great intensity the heat originally generated by the precipitation towards their centre of the immense masses of nebulous matter that compose his mighty globe. In the same way it can be shewn that heat can be converted into electricity, chemical force, magnetism, and light. In short, each of these into all the rest; and not only so, it will probably soon, with regard to all of them, be a demonstrated fact that a given amount of any one can be changed into an equivalent amount of any other.

This brief statement will, I trust, make it plain how it is that in these latter days all scientific research has come to mean the following up of this all-pervading force into its minutest and remotest ramifications. My concern with this great law is twofold. First, to determine, if my time allowed, its metaphysical bearing—i.e., What, on the admission of its truth, are we thereby compelled to believe regarding the reach of our faculties and our relations as reasonable accountable beings to this mysterious Power. Second, how far nerve force, considered as a member of the correlated group, exhausts the mental phenomena of man.

On the first of these points my remarks must be very brief, if I am to leave any space for the second. I must content myself with sifting to some extent this idea of an indestructible force. Now that we have got it, what does it amount to? Is there a limit to the scientific explanation of nature? Can we go on for ever including the effects of her forces in classes of ever-widening generality? We start with some actual experience of force—say the force of my muscles in grasping this table; or, better still, a shock of electricity. We explain this by showing that electricity is merely a mode of heat, as heat is a mode of motion, and so on, till we come to a class so wide that we cannot merge it in any wider, and our power of explanation is ended. Begin at any point you please, with any kind of human experience, you find that you understand only as you are able to generalize it. You rise from special to general, till you reach a species so wide that you have no genus to bring it under. With its co-ordinate it forms the sum mum genus—the outermost barrier of science—the circumscribing limit of the restless intellect of man. All the separate effects that constitute the sum of things are daily becoming more and more reducible to some of the correlated group. These themselves are reducible to heat, and heat is matter-in-motion. Here, as before, we are face to face with the insoluble. We have reached the loftiest summit in the universe of thought, only to find that what we have gained in extent of view we have lost in nearness and fulness of intuition. Our horizon, it is true, is immensely widened; but, on the other hand, we see but a hazy outline of the largest features of the landscape, while all the rest page 65 have faded from our sight, and baffle the keenest eye. Of matter or force, as of any other ultimate idea of science abstracted from the actual concrete facts by which they are suggested, or in which they are embodied, we can make—nay, are logically compelled to make—directly antagonistic assertions. We are in a region where contradictions are equally unavoidable, yet equally unthinkable; and no human intellect is adequate to saying which of them, or whether either is true, or to furnish the verification required. We cannot think of matter except in terms of force, nor of force except in terms of matter. With regard both to the one and the other, all that science can tell us only brings into clearer relief how much remains unknown. Take any force you like, any form of matter, you are driven at last to admit that the only forces we know anything of are the forces that affect our own consciousness, that these are not persistent, but the reverse; that the force that does persist is beyond our consciousness, except as regards its effects alone, and that of its ultimate nature science can tell us nothing. Thus is clearly marked off the sphere of science. Her concern is with the relative, and beyond this she cannot penetrate without losing all claims to credence and all title to respect. Beyond this relative lies a real absolute, now and for ever beyond the province of science to meddle with. If ever, therefore, the man of science forgets this, he meddles with what concerns him not, and about which his science can tell him nothing, except that it exists, and that to its existence it is due that either he or his science has any place in the order of nature's phenomena. Thus by persistence of force we mean really the eternity of some mysterious Power that transcends our widest conception. In the very act of grasping the idea of any actual force resolvable into one central reservoir of energy infinite and therefore incomprehensible in its vastness, we are by the very constitution of our minds compelled to believe in, though we cannot cognise, an Almighty Being, none other than the Almighty God, who is the absolute antecedent of all the consequences we see. This is the absolute, the subject-matter of revelation, just as its relative manifestations are the subject-matter of science. Religion has thus nothing to fear from the most inexorable logic of science. Nor indeed, does science any longer pretend that she has—at any rate, in so far as she has learned to profit by experience. She takes to herself the relative as her portion, refusing to meddle with her sister's domain.

I turn now to the second of the two points mentioned above—namely, How far does nerve force, supposing that it really is a member of the correlated group, exhaust all the facts of consciousness, and enable us to make a complete synthesis of man's nature?

The food of animals consists mainly of the flesh of other animals and vegetable products. Its mineral constituents—viz., water page 66 and common salt—may in this connection be overlooked. Animals require that their food be previously elaborated for them in the less complicated organisms of plants before it is fitted for assimilation by their own more intricate digestive apparatus. Clearly, then, in following up this correlation, I must begin with the food of plants. All vegetable life is dependent for its food on the inorganic materials it finds in the air and in the soil. From these it not only derives food for itself, but elaborates and stores up food for animals and men. Some plants, represented by the pea and the bean, yield the albuminous substance, casein; while the other two great types of animal aliment—viz., saccharine and oleaginous matter—are produced abundantly by multitudes of plants. The cereals alone produce the whole of these in great abundance, and in such fitting proportions, that "bread" is aptly called the staff of life. Thus, the agents at work in the production of this completx result are—the heat and light of the sun, to begin with. These are expended in preparing for the plants their food, i.e., in decomposing the carbonic acid and water, of which their food consists. For these compounds must be broken up before plants can assimilate the carbon and the hydrogen, of which their tissues are mainly composed. Plants, then, exposed to the sun's rays, prepare, as we have seen, the food of animals. But more than this, they exhale the oxygen which animals live by inhaling, and remove by absorbing it, the carbonic acid, which is poison. Plants expire through their lungs the leaves, and cast out as useless, oxygen, which to animals is the breath of life. Similarly, by a beautiful adaptation, what animals expire with every breath as something to be got rid of at any cost, plants inspire at every pore, and then restore it as vital air, or store it up for future use as fuel and as food. The sun's force is expended in producing food for plants. This food goes to build up their tissues. These tissues and the substance they secrete become in their turn the food of animals. Passing over the process of digestion, let us suppose that the nutritive ingredients of the food have found their way into the blood, and are ready to be assimilated, What is the sequence here? The tissues of the body, like everything else in nature, are in a state of unceasing change, and this succession of changes is essential to the continuance of life. The more actively the vital powers are exerted the more rapidly do the organs waste, demanding therefore more frequent and abundant supplies of materials for repair. A constant waste goes on, increased by every exertion even the smallest of body or of mind. New particles are being constantly deposited to replace the old: each of these, after contributing its share of the animal activity, becomes effete, is decomposed and got rid of, only to be followed by an equally fleeting successor. The force stored up in these particles has already been traced to the sun. They are so many minute reservoirs of force, and this force is page 67 liberated by burning, or as it is learnedly called, oxidation, precisely in the same way as heat is evolved from coal in an ordinary fire. The blood, supplied with a continuous stream of oxygen through the lungs, brings it into contact with those particles of which the whole body, muscles, bones, nerves, and brain are composed. The oxygen oxidizes, that is, burns them, and from their combustion is evolved all the force that is expended in the activities of the animal frame in keeping up the bodily heat, in muscular exertion, and the phenomena of mind. In short, the stomach is a furnace: our food, whether vegetable or animal, is the fuel; our bodily warmth, our muscular vigour, our nervous force, i.e., our mind, with all its feelings, thoughts, and emotions, are the ways in which the force evolved in this combustion is consumed.

Suppose, then, a man in ordinary health, and sufficiently supplied with food. This food is oxidized or burned, and a definite amount of force capable of endless transformation is the result. This force is the man's capital, let him spend it as he pleases. An easy mind and a good digestion are the great conservers of vitality. Possessing these, a man sufficiently pachydermatous, not troubling himself about lofty ideals, or the other causes thus originated that harass other men, is most likely to live long and, in his own sense of the word, happily. If, however, too eager to lead such an ignoble existence, a man's brain is active whether in doing, or suffering, there is less power forthcoming for the other purposes of the economy. The muscles, lungs, and other organs, are badly supplied, health is deranged, and life itself is shortened. On the other hand, a man using his brains but little, whether in study or in the wear and tear of business, we ordinarily find his frame more athletic, his muscular vigour greater, and his general health unimpaired.

Yet another step we can go in this direction. The mind is scientifically divisible into Feelings, Volitions, and Thoughts; or Feeling, Will, and Intellect. Given the ordinary mental power of an individual man: If his feelings are very sensitive and acute, there is so much the less force in his intellect; and his will, similarly a very obstinate and inflexible will, drains the intellect and the feelings. It is, however, intellectual activity and waste that causes the greatest drain of all; hence the great tendency of excessive activity here to shorten life and make prematurely old.

An evident corrollary from all this is, that intellectual eminence of the highest degree in more than one widely divergent department is beyond the power of any single mind, even the greatest.

This line of thought, though full of applications to education and the practical conduct of life, I cannot longer dwell on. Up to this point I have been occupied exclusively in approaching my own proper subject from the physical side, my purpose being to make the alleged sequence intelligible so far as to put you in possession of materials for enabling you to follow intelligently the page 68 nature and bearing of those physical discoveries and controversies of the day that are destined to influence so profoundly the future of Psychology. It is not possible, in the course of a single hour, to entertain any of the questions that must at every step have pressed themselves on your attention in following my argument. For instance, What is the nature of Vitality and its relation to the "Physical bases of Life?" Is it a mere question of collocation of matter, or is it not rather something unique in its nature, nullifying therefore the whole position that mental are merely physical forces transformed? One question, however, because of its present interest, I cannot help touching on before I close, namely, the relation between mind and brain. The materialist on the one hand affirms that brain thinks in the same way as muscle contracts and the liver secretes bile; on the other hand psychologists maintain that between the molecular movements of the grey substance of the brain and thought there is nothing in common save degree and duration in time. The truth is wholly with neither. It is true that our mental phenomena and the accompanying molecular movements in the nerve centres are inseparable in fact, and unthinkable apart. But the nature of their connection is as far from being understood as ever. We accept the fact as a conjunction unique in nature, the extremes of human experience—mind and matter welded into one, yet offering the widest contrast in the universe of things. Does any one affirm that it is a case of causation? Then which is cause, and which effect? If you ask the materialist what he means by matter, he cannot define it otherwise than by saying that it is something occupying room in space, i.e., something extended. The corresponding definition of mind is, that it is something unextended that occupies no room in space. The one you must think of as in some place; the other you cannot think of as in any place. Nay, more: In the very act of thinking of the one you are, so to speak, at the point the farthest possible removed from the other. No one effort of mind can compass them both. The world of mind and the world of matter are still as distinct as ever; and yet it is true that every fact of mind is equally a fact of matter; and the peculiarity of mental science is, that every phenomenon within its borders must be studied under two totally different aspects and by two totally different methods. Physiology and Psychology are thus happily agreed; and, as always happens when ideas hitherto antagonistic unite, each containing its quantum of truth, there is reason to expect a rapidity of progress hitherto unknown.