How can we know? How can we understand?

. . . . . . . .

How can we know, who know our truth is based

On finite facts by infinity effaced,

By parallels that meet in space behind,

On matter that is force, unconscious, blind?

How can we know whose knowledge is so small?

. . . . . . . .

How did the Chaos burgeon into life?

Did it imagine, when the toil begun,

‘Twould blossom into star, and moon, and sun,

Rolling to rhythmic music? Toil seemed vain.

Mistily, vaguely, dizzily it spun

Racked with strange pain,

In fiery rain,

Through black abysses, while the cosmic power

Compelled it into bird and beast and flower.…

. . . . . . . .

Truth is eternities away,

And we but climb

In the dark of Time,

To the dawn of day.

Macfie

In the great arch of night above our heads about five thousand stars may be seen by the naked eye. In their marchings and counter-marchings they make a brave show, yet are in fact scarcely so much as a swarm of bees in all Asia, a spray of blossom in the limitless abyss, where ‘a hundred thousand million stars make one galaxy, and a hundred thousand million galaxies the universe’. The stars we see are but a handful, and their removal would not disturb by as much as a decimal the calculations of the Angel of their courses. We may be sure that for every human being in the world there is not one star apiece—there are ten thousand. Viewed from the bodily angle, no comparisons can express the insignificance of man among the cosmic magnitudes upon which our astronomers exhaust their eloquence. Theirs is a terrifying artillery. Under the bombardment of their dimensions and distances the spirit shrivels. We are afraid, and the marrow of our bones is dried up With time and space as their allies they diminish us to pitiable atomies. The earth is a mote of dust, and the sun itself a diminutive fire-fly. We inhabit the puny satellite of an inferior orb. There are millions of stars so immense that room could be found for millions of our petty sun in one of them.

If you are not already dizzied by magnitude and number in these expanses, you may proceed to ponder the multiplicity of motions, the comings and goings of these celestial armies, beginning with the diurnal and annual circlings of our own planet, the wandering of its poles, the journey with its companions towards the constellation of Hercules at the rate of two million miles a day, and concluding with the grand revolution of the starry system to which it belongs, completed once in two hundred and fifty million years.

The physicists and physiologists emulate the astronomers and paralyse our faculties with a like arithmetic. There is an inner deep to match the outer. A drop of water confounds us. It contains millions upon millions of molecules, and you may say galaxies of electrons. Each liver cell in our bodies is composed of three hundred billion atoms. Light, you think, is a rapid messenger, since it can travel seven times round the earth in a single second. Yet it brings late news of cosmic events. A great flare in the heavens, observed in 1901, the result probably of some stellar collision, took place, it is calculated, in 1551, when Edward the Sixth was king, and what the telescope reveals to-day in the nebula of Andromeda is a very old story of happenings a million years ago, so long has it taken that lightning flash to reach us across the stupendous gulf. And where were we, and what the human race, when that beam shot forth on its journey? And how in a universe so wide can we creatures of a day continue to strut, and pose and bluster, or look upon ourselves without contempt?

Yet it needs not to muster battalions of facts like these to reduce us to a proper humility. How slight a thing is man amid the works of man himself! The pyramids belittle the Pharaohs who built them, and men are humiliated by their own monuments. Caesar in his capital, amid the temples and palaces of Rome, presents but a poor appearance. The bishop beneath the soaring towers of his cathedral, the captain on the bridge of his battleship, a fabric of vast and intricate design, hurling thunderbolts, is no considerable object. They are barely visible, these men, amid their magnificent surroundings.

What then are we to conclude, and what moral draw? Are we to accept a timid inferiority, abase ourselves before the work of our own hands, rank the sculptor lower than his image, the architect of St. Peter’s less than his creation, estimate Socrates or St. Paul by their stature, and fall on our knees before the Milky Way? This were, indeed, a grotesque transvaluation of all values. I am unable to accept the philosophy either of the telescope or the microscope. Kant reverenced the starry heavens, and no doubt did well to do so. Hegel despised them. For all their luminous splendour these majestic constellations are for the most part mere balloons, spaces filled with gas. Disdain or reverence them as you please, to be overpowered by mere magnitude is preposterous. ‘This,’ said Malebranche, when he first saw a microscope, ‘This is the end of size’—a sane and penetrating judgment. ‘Large’ and ‘small’, what is the meaning of these words? None, save the meaning we give them. And what is the unit of these measurements? The unit we assign. Size is a matter of comparison, as is heat. The degree of heat on a scale of temperature is without meaning when applied to a single particle. There is no such thing as an absolute standard in the physical world. These estimates are of our own devising, governed by the scale of our bodies, and their adaptation to the surrounding phenomena.

Nor between size and quality is there any calculable relation. No one can measure for you the length and breadth of beauty or desire, and none is so foolish as to judge a canvas of Da Vinci’s by its extent, or apply a footrule to the Dialogues of Plato. How insignificant a trifle, if you care to pursue such comparisons, is the eye itself. Here are no imposing dimensions, yet it is a signal triumph of nature, possessing powers the lordly constellations appear to lack. There are in the optic nerve half a million fibres, and some millions of cells in the retina. They work in concert. Perhaps the eye should be to us a source of deeper wonder than the stars. Perhaps the material perspective, which assigns the nobility to the scenery rather than the play, is the most distorting and the cheapest of all our many illusions, overlooking, as it does, the mind, ‘which measures every wandering planet’s course,’ knows more about the stars than ever they knew, matters of which they are wholly ignorant, and will be, for all their superb proportions, till their dying day. St. Augustine declared the human soul, even the animal soul, of greater dignity than the entire inanimate creation.

Natural it is, and indeed inevitable, that visible things should in daily affairs take precedence over the invisible. Reasons are at hand. The eye is a compelling and persuasive witness. ‘It cannot choose but see.’ It has its office, and performs admirably the functions of its office. And to unreflective minds the external world appears the sole and enduring reality. By comparison how pale are our thoughts, those bloodless, flitting shadows; what a misty twilight realm the mind’s. From this illusion no doubt nature intended us to suffer, an illusion similar to that which assures us that the earth is flat and motionless, though the contrary is the truth, that it is a sphere and its motions many.

The world includes this trifling object, man, as it includes the primrose and the cloud. Yet, by a curious paradox, in its comprehension this puny object goes beyond and includes the world within which it is found. Man is at once contained within, and himself contains the world in his thought. Thus, if his outer and physical vision minimises his importance, his inner and intellectual restores and enhances his estate. The shining systems hung in the heavens, like the great prehistoric monsters of earth’s earlier days, have nothing but their bulk, their hugeness, with which to astonish us. They have neither theology nor mathematics. They neither feel nor understand. Nature, ‘the lonely, with her sightless eyes’, what value or significance, without us, or other similarly endowed beings, has her existence at all? A universe without spectators! Ponder that idea. Indeed it is a question whether we have here an intelligible proposition. Certainly in that solitude, if it be imaginable, in a scene without spectators of the scene, it matters not at all what happens, if anything can be said to happen, where nothing is anywhere, at any time, by anyone seen, heard or known. A universe sunk in the abyss of everlasting neglect, from which it might as well never have emerged, since no word of it, no thought of it, has ever been whispered, can it be described as in any intelligible sense existing? Remove thought from the scene, and all the worlds vanish, they are lost in the darkness of primeval night.

This is not a matter to be lightly passed over. Say what you will, in us nature comes to life, and before this rising from the dead we are speechless. Do you ask me to believe that nature overstepped herself, making she knew not what, and what she need not have made? Do you tell me that consciousness,

The eye with which the universe

Beholds itself, and knows itself divine,

is simply a thing among other things, to be placed alongside the river or the stone? I shall not be easily persuaded—you strain my credulity, gentlemen. You are of the opinion that the arrival of the audience in nature’s theatre was an irrelevant accident. See now how minds differ. It would be for me too apropos and brilliant an accident, too startlingly relevant an irrelevance. You have not crossed the Pons asinorum of philosophy until you have perceived the necessity of mind, that upon its operations, its recognitions and appreciations all hinges, that in thought you have the end, and aim, and justification of nature. I conceive that we miserable atomies have some business to be where we are, a function, and no inconsiderable one, a place in the procession, since there is no view without the viewer, no measurement without the measurer, no knowledge without the knower, in effect no universe without an intelligence to be aware of it.

It appears, to me she knew very well what she was about, this lady nature, that she foresaw more and provided for more than we imagine—in a word, is not so empty-headed as we suppose. She took pains at least not to be a wall-flower, passed by without notice. She had a fancy for an audience, for admirers. Can we imagine Being, as Plato asked, to be devoid of life and mind, and to remain, in awful meaninglessness, an everlasting unseen empty picture? Let us say for the present that life, consciousness, mind have not strayed accidentally into the universe. There never was a cosmos without life, consciousness, mind. They are among its attributes, constituents of its innermost being.

You cannot, indeed, lay violent hands upon thought, yet ideas, whatever they are, exercise a wide jurisdiction. Why is a scientific theory accepted or rejected? Because reason lays down its law. What is this pallid ghost, reason, that it dares to intrude into the proud and glittering assembly of substantial things, this insolent pretender to authority, which goes about to question the testimony of the senses, this self-appointed magistrate over the heavens and earth? What is this ridiculous shadow, which in the majestic presence of sun, moon and stars should be treated with imperial scorn? The world lying there before us, just there, despite of us, stern and irremovable, clear, sharply outlined, wholly independent of us, and all that we do and think—that world surely brooks no denial, and needs no supporting arguments. Nature as she truly is, this is the nature of which science desires knowledge, virgin nature, apart from its perception by any human eye or living thing, unaffected by any contemplating mind, nature as she was before the eye was fashioned or the mind was born, a nature without spectators. Surely a most desirable knowledge. By all means let us have it. The chief aim of science throughout its history has been to avoid the confusing and exasperating intrusion of the observer, to elude his presence, to suppose him not there, on a journey, or attending to his private affairs, or gossiping with his neighbours. But how are you to get along without him? There’s the ever-lasting rub! How are we to cut his acquaintance, or give him notice to quit?

The Greeks were accustomed to speak of the peripeteia, the change or reversal in fortune or circumstances which marked the turning-point in a drama. Such a peripeteia took place about the beginning of the present century, a reversal, a crisis, which, though many workers are hardly even now aware of the convulsion, shook the citadel of scientific thought to its foundations, and as a philosophy, left it in ruins. Science stumbled upon the vital mysteries, and awoke to the true situation. Of this revolution Relativity theory and Quantum theory were merely the heralds. It displays itself, and is, in fact, the discovery by men of science of the metaphysical assumptions in all their reasoning, the least expected and by far the most momentous of their many and brilliant discoveries. In their eagerness, in their triumphal progress, they had accepted without enquiry the plain man’s view of the world, assumed, like him, space, time, motion, causality and all the rest, at their face values, and suddenly found themselves immersed in ‘the great Serbonian bog, where armies whole have sunk’. Without exception the sciences involve these, and a dozen similar concepts, and all had been taken for granted, all employed as if in no need of scrutiny.

The crisis came when the structures of science were seen to be, like the child’s buildings on its nursery floor, constructed out of obliging blocks, and doors and windows, all supplied, already adapted to meet the necessary requirements of the young architect’s design. But space, time, motion, causality are not things, they are not objects, they are concepts of the mind, and the moment you mention them the thinker is at your elbow. In daily life we are not concerned with an interpretation of the sum of things. We may take matters as we find them, without anxious enquiry into their nature—the sights and sounds, the motions and the causes. But begin to philosophise, to speak of the ultimate, reality, of things as they really are, and all this must cease.

The crisis arose with the recognition by men of science that to the external world of their investigations there is only one door, the door of human consciousness. Before you can examine things you must first become aware of them. More than that, in all your observations you carry with you the prepossessions of the observing mind itself, its powers and prejudices. That is to say, the observer is a part of his observations. But since the Renaissance science had taken the mind for granted, and as having no hand in the game; it supposed itself dealing with virgin nature, pure and undefiled, uncontaminated, in no way affected by human thought. And lo, looking over his shoulder, or rather in the very recesses of his observations, the man of science found the companion he most desired to avoid. Do what he would, he could not rid himself of the society of his own mind. Like the old man of the sea on Sindbad’s shoulders, it clung to him, and could not be shaken off. With what result? That the concepts of the mind, all its prepossessions, entered into, became a portion of, and affected his findings. He had regarded thought as ‘a mere pensioner of outward forms’. Now into the broad sunlight emerged the menacing, incontrovertible truth that in the picture he drew of nature he was invariably himself present, and that his presence gave to the picture features which virgin nature never had, nor could have. In a word, science discovered philosophy, in which it had steadfastly refused to believe, and had supposed a negligible flibbertigibbet.

A cloud, the size of a man’s hand, first showed itself on the horizon—the affair of the so-called ‘secondary qualities’. Of what colour is an electron? The light from a receding star, say the astronomers, becomes redder, from an approaching star violet, and base calculations upon the colours exhibited. But what if this redness is neither in the star nor in the garden rose, any more than the pain is in the knife that gives you pain, or the pleasure in the flower that gives you pleasure? At first it was supposed that the observer merely touched up the original canvas of nature a trifle by adding the secondary qualities, like colour, smell, taste; but, upon further analysis, the primary qualities, so-called, like resistance and extension, went the same way. They, too, were seen to involve a subjective judgment. Things or objects vanished, they became, in Professor Whitehead’s phrase, ‘nothing but an average stability of certain events in a set of agitations’.

Presently out of the cupboard emerged all the metaphysical skeletons, the everlasting unsolved enigmas. No account of the world, to put the matter in a single sentence, scientific or any other, can go beyond this point, that it is the world as experienced, and experienced by an observing being, who brings with him the mysterious faculty of experiencing. Nature apart from ourselves, and the mind in ourselves, we simply cannot know, and must not pretend to know. Outside ourselves we cannot travel by any gymnastics. To sketch the landscape as it appears to no one, while it remains unseen, to think in the absence of any thinker, are difficult operations. Do not mistake me. By most philosophers it is agreed that over against the thinker there certainly exists a universe not of his making, a world ‘common to all’, as Kant expressed it. To its true character, nevertheless, no one has found the way. Some link there is between them. We cannot believe that the observer and the world encountered each other by accident one fine day in the vasty fields of space. But how are they connected? All we can say is, no observer without a world, and yet no world without an observer. Or again, in Kantian language, perception without conception is blind, conception without perception empty. We can come to no other conclusion than that the marriage of things and thought is indissoluble. What God has joined no man can put asunder. Nature intended mind, desired to complete herself, to make an entry into society. It has the look of a clearly defined undertaking.

How, then, you will ask, does science live and flourish? Not by its theory of knowledge, for it has none, nor by its philosophy, if it can be said to have any, but by its technique, its methodology, by the brilliant success of its practical achievements, which have conferred innumerable benefits upon mankind, and won for its pioneers their immortal and deserved renown. How weak is science in explanation, but how mighty, how impressive in action! Mind is the veritable throne of science, and all lovers of knowledge bow before it. Yet betrayed by some inexplicable perversity, or some mad ambition, many of her disciples keep company with a proletarian metaphysic, declaring at one moment that consciousness is an irrelevance, an empty shadow, an epi-phenomenon, at another that it is a mode of energy, like heat or electricity, and by either route plunge at length into a vortex of perplexities, and make sorry work of their own conclusions.

Yet how is an exit to be found? If we are to be fair, we must allow that science is in a dilemma, revolving in a closed circle, and by her own choice left without an alternative. When I speak of science I mean materialistic science. There is no other. Possibly the statement surprises you. Yet surely it is obvious that science and materialism are one, and cannot live apart. They condescend to recognise no world save that which can be seen, touched, handled and measured. On sense experience, analysed, probed, expanded, and on sense experience alone, the whole structure of both is founded. What can you do? Matter talks matter, and science knows no other language. To admit any dimension or order other than the physical would be to abandon the ground on which she stands, to sell the pass. Suppose another order to exist, suppose an independent world of thought, science has no means for its exploration. There is no scale in physics for determining, let us say, the value of a poem, or the aspirations of a saint, no instruments for the measurement of Milton’s imagination, or Rembrandt’s soul. What follows? If you speak of such things at all she is willy nilly driven to declare that these also, in the final account, belong to the material system, and are in the end composed of electric charges. Of what else can she say they are composed? To admit a world beyond her powers of inspection would be to sign her own death warrant. Worst of all, it would open again the door, which at the Renaissance was slammed and barred against the myths and superstitions in which men had so long and fondly believed, the chaotic fancies, unchecked and uncontrolled by experience and experiment. Leave the plain world of the senses, and what foothold have you, what security? You enter a region where anything may be asserted, and anything believed.

Europe at the Renaissance submitted itself to a new discipline, and substituted nature’s textbook of observable facts for the book of poetry. It was a momentous decision, a crossing of the Rubicon. The die was cast. So it came about that life, mind, consciousness came to be declared the resultant of physical processes, and to prove them so became the goal of scientific endeavour. ‘The aim of modern physiology’, says Höffding, ‘is to conceive all organic processes as physical or chemical.’ If this key will not fit the lock, science does not look around her for another. She admits no other, for she has no other. She files and oils the old key, and clings resolutely to the hope that some day it will be found to turn the wards.

The verdict to be reached is determined before the evidence is taken, the conclusion that the whole history of life and mind, the music of the poets, and the thoughts of the thinkers, the religions and policies, all loves and tears and laughter, fears, despairs, hopes and ideals, can be unequivocally explained in physico-chemical terms, that the study of man, no less than that of nature, is simply the study of what the senses reveal and in the end of physical chemistry, to which without remainder they can be reduced.

By the thinkers among men of science this vaulting programme has now been tacitly abandoned. The day of reckoning has dawned, or if you will, the day of sanity. How has it come about? So complicated is the story that onlya genius could present it. Bear in mind that physics cannot outsoar or transcend physics, a physical enquiry can only end in a physical explanation. Bear in mind also that all the sciences follow in its wake. If all things are built, and weare assured they are built, of unsubstantial, flying swarms of electrons, biologists must remember that all organisms consist of them; physiologists must not forget when they speak of thought, of will, of passion, that they are speaking of the subtly-woven products of this spider’s web of spinning charges, however absurd it appears. To this its unassailable sovereignty, physics owes the breathless attention with which we follow its thrilling career, its exhilarating pursuit of the ultimate reality, the fundamental constitution of things.

What, then, is the latest news? Two bodies of explorers are at work, one company upon the large-scale phenomena in the telescopic heavens, the structure and motions of the starry systems; the other upon the small-scale, the microscopic or sub-atomic phenomena, and in both regions the Olympian mathematicians preside over all the deliberations. The latest news that has reached us, as everyone knows, may be summed up in four words—Relativity theory and Quantum theory. Four words! Or if we add Radio-activity—five words. But how startling, how revolutionary their message. Yet it is not one message but two, for these theories conflict. The small and great phenomena are not on friendly terms. Quantum theory has not been assimilated by Relativity theory, and it would not be too much to say that bewilderment reigns in both camps.

Consider the situation. Matter, a substantial something underlying and supporting its various qualities or appearances—colour, hardness, weight—is an ancient and time-honoured conception. It has had a long and successful life, but senility has overtaken it. By degrees its powers began to fail; its mass was found to vary with its velocity, a strange thing: then energy and mass were found to be identical, and matter finally became another name for energy. We must now, it seems, define matter as ‘a complex of gravitational, kinetic and chemical energies which are found to cling together in the same space’. We think of gold, for example, as a solid body, but it is chiefly empty space. We scarcely recognise our old friend, matter, for which physics has no further use. A kind of visible motion, without substance, has taken its vacant place. There are no static things or objects, located in fixed positions. All is process, movements, events, some slow on our scale, like the drift of continents, some fast, like radiation. There is nothing either permanent or indestructible.

Stranger still, the new view declares that matter, whatever it be, and however it be described, is utterly inert, and without initiative, a do-nothing, an incorrigible idler. Pushed and pulled here and there, it is in truth merely the evidence, or index to our senses, that a power not its own is at work in the neighbourhood. Do not fancy—it is a very common error—that electrons and protons are material particles, carrying electric charges. They are not substantial things at all, they are not incarnations of energy, they are simply atoms of electricity.

The scene has changed, and with a vengeance. The new view maintains that it is not in matter that the energies of nature reside, but in what seem to us the empty intervals, the vacant spaces between objects—it is there that all the activities of nature have their unseen habitation. They reside in the electric, magnetic and gravitational fields, of which we have no perception at all, of which our senses tell us nothing, and of which till yesterday the very existence was unknown. Tangible and visible things are but the poles, or terminations of these fields of unperceived energy. Matter, if it exists at all in any sense, is a sleeping partner in the firm of nature. Space has taken over the concern, and does the business in the back premises. All that happens, happens in the void or vacuum, to which we give the name of space.

What, then, is this industrious space, which we had imagined to be pure, idle emptiness? That concept, too, has a curious history. For ages thought of as ‘a universal container’, as doing nothing and simply there, a kind of listless, unoccupied Absolute, we must now think of it as a factory of unseen humming batteries. With Faraday and Clerk Maxwell came the notion of space as filled with an active ether, a hypothetical medium, which served as the vehicle for electro-magnetic phenomena, like those of light and heat. Some medium had to be found, and yet no trace of the indispensable vehicle could, despite the bravest efforts, be discovered. How was this difficulty overcome? Most simply and ingeniously. True, it was said, we cannot find ether anywhere, but here is space: let it undertake the necessary duties. So ether was summarily deposed, and space crowned in its stead. Finally, as you are aware, on a suggestion of Minkovsky’s, time, previously regarded as a separate entity or concept, was united to space and a joint monarchy proclaimed.

Such, in brief, is the romantic story. This Space-Time, you are to remember, has now been endowed with physical as well as geometrical properties. It has become a substance which behaves differently in different places. There is radiation in space-time, many types of it besides light. It is a hive of prodigious, of furious activity. Beyond the visible spectrum there are electro-magnetic, infra-red, ultra-violet rays. There are X-rays and γ-rays, all differing from light only in respect of their wave-lengths. There are alpha-rays, which radium discharges with the velocity of ten thousand miles a second, and there are the recently discovered cosmic rays, of penetrating power two hundred times greater than any of the rest, and more powerful by day than by night, whose source no one knows.

Viewed through Relativity’ theory and Quantum theory, as through a pair of binoculars, the universe presents a bizarre appearance. The first, Professor Einstein’s dazzling conjecture, is not indeed universally accepted, yet is none the less a masterpiece of human wit. It declares that you desert meaning when you speak of simultaneity, a common time throughout the universe. Each moving system has its own. Each of us carries a local time about with him, his private watch. It declares that there is no sense in speaking of distances or durations save within a selected frame of reference, or in talking of matter, which is a misleading name for energy at a certain velocity. Further, among various possible geometries, Professor Einstein adapted from Riemann a geometry which differs from Euclid’s,1 which accounts for gravitation in a wholly different manner from Newton, as the result of space-time properties; and so dispensed with the old notion of a pull or attraction between bodies at a distance from each other—a mysterious force implied, but unaccounted for, in the Newtonian scheme. It substitutes, however, one mystery for another, since not so much as the glimmer of an explanation is offered why the presence of a large body should curve or distort the space in its vicinity, or why space should be so described at all.

In these regions you and I are manifestly not entitled to any vote. This only can be said, that a strong body of dissentients rejects the Einsteinian doctrine. For the ascription of physical properties to space, for the assumption of warps and creases in that medium, there is, they contend, neither need nor warrant. The geometry is an arbitrary choice, selected to provide the desired results, and the facts may be explained without the abandonment of the Euclidean system. Space and time, moreover, it is argued, are not homologous, or structurally alike. Time has a past and future of which space knows nothing. Geometry takes no note of time, and is independent of time, and to talk of motion as if it were a thing, as in itself curved, or possessing velocity, is to plunge into a swamp of nonsense. Time, too, of which we have an inner consciousness, is more comprehensive, more fundamental, than space, and of deeper metaphysical significance. So the malcontents conclude that the Minkovsky hybrid, Space-Time, is an arbitrary and untenable construction. Professor Milne, for example, employs the idea of a non-physical space, constructed out of temporal experience, regarding length and distance as combinations of time measures, which alone are taken as fundamental. Space-Time as an objective entity he thinks the purest fancy, and Relativity is for him merely ‘the comparison of the experiences of different observers who can communicate with each other’.

From any standpoint the devastation wrought in all our previous ideas is shocking. Gravitation—well, it seems that in certain parts of space, repulsion and not attraction may be at work. The velocity of light may not after all be a constant, for in a gravitational field it follows a curved path. Causality, the granite foundation, without which, it was supposed, no scientific progress could at all be made, is in many quarters more than suspect, and on the way to be abandoned. For Lord Russell it is ‘a relic of a bygone age’. ‘An Indeterminacy principle’, or ‘waves of probability’ are installed in its room. Atomic phenomena are not predictable. A rift has appeared in the causal sequence. For all we can tell, these phenomena may even be controlled by a power external to physical nature, an angel or a God. From the same state of things, from a given initial condition, not one deter-mined result only, but various results may follow. An atom of radium may for no ascertainable reason disintegrate to-day or next week, or last a thousand years. Our familiar friend, light, presents an insoluble conundrum. No one can tell you what it is. Certain of its aspects can be accounted for if you suppose it a wave motion, others if you regard it as a beam of travelling photons or particles. If you adopt the first opinion diffraction remains an enigma, if the second, the photo-electric effect disputes your passage. Stars, hills and seas, the furniture of earth and heaven, fade away into a mathematical residuum, into equations. Space-Time alone survives, a strange monster, with a physical head and a metaphysical tail, unheard of in any previous history. We are left with Space-Time and its configurations, that is, with configurations of we know not what.

A year or two ago Professor Einstein calculated the size of the universe. It was finite, and its diameter was 216 million light-years. It now appears that his calculations may have gone astray. It may, after all, be infinite. One is not greatly surprised. Anyone of us can tell, even you and I, that it is one or the other. Yet if infinite it is not curved, for infinity has neither shape nor boundary.

Do not, I pray you, fancy even for a moment that I take pleasure in the perplexities of these brilliant pioneers. I have much too deep a respect for talents far outranging my own. I desire to claim their feats for that divine investigator in man we call the mind. From any angle I cannot bring myself to think it secondary or derivative, to describe it, with Hobbes, as ‘nothing but local motion in the organic parts of man’s body’. Motion enquiring into the character of motion, matter looking into this little affair of its own construction! How interesting are such ideas. Can matter come to think? It will be time enough to consider the question when we have been told what matter is. Science, the science of molecules and atoms, of protons and electrons, of measurements and the calculations of energy, stands across the path of its own philosophy with a drawn sword. Energy is translated into energy. The motions of the atoms of the brain must therefore pass into other motions. There is no end or exit from this closed circle. If consciousness emerges, if hopes and fears emerge, if sympathies and affections, science should tell us ‘Into what other physical motions do they pass?’ What movements do they in their turn set up in the world of atoms? You must not tell us they do nothing, or are mere witnesses of the unending performance. We must be told what in the physical system do they move. This gulf remains unbridged.

For myself I am of the contrary party, which holds, with Cud-worth, that mind is ‘senior to the world, and the architect thereof.’ Thought is at least an indisputable factor in the scheme of nature, and by thought alone can it be studied. The vast and imposing array of scientific facts, observations and measurements, what are they but findings of the mind, and how can they be reached without the organisation provided by the mind? How else are they arrived at? The primacy of thought consists simply in this, that everything is submitted to its judgment and valuation. There is nothing anywhere more secure upon which it can rest, and the intelligibility of nature we assume has no other assurance. The confusion of our times appears to me the inevitable consequence of an unphilosophical physics, which endeavours to explore the abyss of being, as does Professor Einstein, with material apparatus, with rigid rods and synchronous clocks—God save the mark!—which is based upon physical observations alone, which looks upon space and time as amenable to measurement by laboratory instruments.

I read recently that Professor Einstein has a new theory in mind, towards the formulation of which he has had the aid of some startling new ‘pictures of space’—I quote from The Times—‘photographed with the mathematical “lenses” of a “cosmic camera”. These “photographs” indicate that ‘space is not one thing, but two identical sheets joined by many new bridges.’ These are wonderful thoughts, indeed, and wonderful proceedings. When I read of them I am convinced that I have eaten of ‘the insane root that takes the reason prisoner’.

Quantum theory, which has to do with small-scale, subatomic phenomena, has gone far deeper and nearer the centre than the more sensational Relativity theory. No one disputes its conclusions. We are in the vestibule of the mysterium tremendum. Listen to this. ‘In Atomic Physics’—I quote Professor Dingle, ‘neither space nor time separately, nor space-time has any significance.’ What a thunderbolt! ‘The appropriate substitutes’, he continues, ‘are not yet known.’ No, they are not known, and we may even conjecture that they will be hard to find. A hundred matters of sublime interest confront us. We have, for instance, the theory of the expanding universe, which asserts that the spiral nebulae are receding from us at fantastic speeds, 150,000 miles a second, that the very character of space is changing before our eyes, and that the day will dawn when our successors in this galactic system will say ‘good-bye’ to the rest of the universe, which will vanish from their sight. More harrowing still, we encounter Entropy, the famous Second Law of thermodynamics, Carnot’s principle, which tells us of the one directional movement of nature. ‘Time’s arrow’, as Professor Eddington calls it, points remorselessly one way, towards the degradation of energy, which, in a state of temperature everywhere the same, is paralysed, and unavailable for any rebuilding of the burnt-out Cosmos. The final state of things will be a ghastly lethargy, nothing for evermore will again take place. On this way to death, this descending staircase into extinction, it was that life climbed, against the stream, and put forth all the miracles of living creatures, of mind and all the miracles of mind. So the universe, unable to keep itself alive, is subject to the same dark destiny as its children. It, too, must die, and darkness be left to bury the dead. Well, perhaps, and perhaps not. Physics may not have the last word in cosmic history. The universe has not always been what now it is, and may yet, indeed certainly will, undergo transformations as unpredictable as it has undergone in the past.

Space is thought’s, and the wonders thereof and the secret of space;

Is thought not more than the thunders and lightnings—shall thought give place?

In the age-long encounter between mind and matter, thought and thing, it is not matter which has in our time gained upon its adversary. The standard of mind it is that has gone forward, and is planted on the captured heights. Our successors may look back, I believe they will look back, upon us as belonging to an age in which was fought the greatest and most momentous among the decisive battles of the world.

• 1. In Euclid’s geometry two straight lines cannot enclose a space, and the sum of the three angles of a triangle is equal to two right angles. In Riemann’s geometry two straight lines can enclose a space, and the three angles are greater than two right angles.