For life is but a dream whose shapes return,
Some frequently, some seldom, some by night
And some by day, some night and day: we learn,
The while all change and many vanish quite,
In their recurrence with recurrent changes
A certain seeming order; where this ranges
We count things real; such is memory's might.

From this wealth of observation and record the modern age, and especially the century just past, has developed two fields of intellectual activity to such an extent as almost to claim the creation of them. Gradually through accumulated observation the nineteenth century came to look on human affairs in a new light; like everything else they were seen to be subject to the Heraclitean ebb and flow; and history was written from a new point of view. We learned to regard eras of the past as subject each to its peculiar passions and ambitions, and this taught us to throw ourselves back into their life with a kind of sympathy never before known. We did not judge them by an immutable code, but by reference to time and place. Nor is this all. Within the small arc of our observation we observed a certain regularity of change similar to the changes due to growth in an individual, and this we called the law of progress. History was then no longer a mere chronicle of events or, if philosophical, the portrayal and judgment of characters from a fixed point of view; it became at its best the systematic examination of the causes of progress and development. And naturally this attention to change and motion, this historic sense, was extended to every other branch of human interest: in religion it taught Christians to accept the Bible as the history of revelation instead of something complete from the beginning; in literature it taught us to portray the development of character or the influence of environment on character rather than the interplay of fixed passions; in art it created impressionism or the endeavour to reproduce what the individual sees at the moment instead of a rationalised picture; in criticism it introduced what Sainte-Beuve, the master of the movement, sought to write, a history of the human spirit.

But history, like Cronos of old, possessed a strange power of devouring its own offspring. Gradually, from the habit of regarding human affairs in a state of flux and more particularly from the growth of the idea of progress, the past lost its hold over men. It became a matter of curiosity but not of authority, and history as it was understood in Renan's day has in ours almost ceased to be written. Science on the other hand is the observation of phenomena regarded chiefly in the relation of space—for it is correct, I believe, to assert that the laws of energy may be reduced to this point—and as such is not subject to this devouring act of time. It frankly discards the past and as frankly dwells in the present. It is not my purpose, indeed it would be quite superfluous, to reckon up the immense acquisitions of the scientific method in the past century: they are the theme of schoolboys and savants alike, the pride and wonder of our civilisation. Nor need I dwell on the new philosophy which sprang up from the union of the historic and the scientific sense and still subsists. Not the system of Hegel or Schopenhauer or of any other professor of metaphysics is the true philosophy of the age; these are but echoes of a past civilisation, voices and præterea nil. Evolution is the living guide of our thought, assigning to the region of the unknowable the conceptions of unity and perfect rest, and building up its theories on the visible experience of motion and change and development. It has reduced the universal flux of Heraclitus to a scientific system and assimilated it to our inner growth; it has become as essentially a factor of our attitude toward the natural world as Newton's laws of gravitation.

But if our thoughts are directed almost wholly to the sphere of motion, yet this does not mean that the longing after quietude and peace has passed entirely from the mind of man; the thirst of the human heart is too deep for that. Only the world has learned to look for peace in another direction. In place of that faith which would deny valid reality to changing forms, we have taught ourselves to find a certain order in disorder, which we call law,—whether it be the law of progress or the law of energy,—and on the stability of this law we are willing to stake our desired tranquillity.

In this way, through what may be called the offspring begotten on the historic sense by science, the mind has turned its regard into the future and seemed to discern there a continuation of the same law of progress which it saw working in the past. Hence have arisen the manifold dreams and visions of socialism, altruism, humanitarianism, and all the other isms that would fix the hope of mankind upon some coming perfectibility of human life, and that like Prometheus in the play have implanted blind hopes in the hearts of men. It is indeed one of the most curious instances of the recrudescence of ideas to see the mediæval visions of a city of golden streets and eternal bliss in another existence brought down to the future of this world itself. What to the mystic of that age was to come suddenly, with the twinkling of an eye, when we are changed and have put away mortal things, when the angel of the Apocalypse has sworn that time shall be no longer,—all this, the heavenly city of joy and endless content, is now to be the natural outcome here in this world of causes working in time. The theory is beautiful in itself and might satisfy the hunger of the heart, even though its main hope concerns only generations to come, were it not for a lingering and fatal suspicion that progress does not involve increased capability of happiness to the individual, and that somehow the race does not move toward content. Physical comfort has perhaps become more widely distributed, but of the placid joy of life the recent years have known singularly little; we need but turn over the pages of the more representative poets and prose writers of the past sixty years to discover how deep is the unrest of our souls. The higher literature has come to be chiefly the "blank misgivings of a creature moving about in worlds not realised"; and missing the note of deeper peace we sigh at times even for

A draught of dull complacency.

Alas, those who would find a resting-place for the spirit in the relations of man to man seem not to reckon that the very essence—if such a term may be used of so contingent a nature—that the very essence of this world's life is motion and change and contention, and that Peace spreads her wings in another and purer atmosphere. One might suppose that a single glance into the heart would show how vain are such aspirations, and how utterly dreary and illusory is every conceived ideal of progress and socialism because each and all are based on an inherent contradiction. He who waits for peace until the course of events has become stable is like the silly peasant by the river side, watching and waiting while the current flows forever and will ever flow.

Not less vain is the hope of those who would find in the laws of science a permanent abiding place—perhaps one should say was rather than is, for the avowed gospel of science which was to usurp the office of olden-time religious faith is already like the precedent historic sense, itself becoming a thing of the past. Yet the much discussed war between science and religion is none the less real because to-day the din of battle has ceased. It does not depend on criticism of the Mosaic story of creation by the one, nor on hostility to progress offered by the other. These things were only signs of a deeper and more radical difference: religion is the voice of faith uttering in symbols of the imagination its distrust of the world as a scene of deception and unreality, whereas science is the attempt to discover fixed laws in the midst of this very world of change. If to-day the strife between the two seems reconciled, this only means that faith has grown dimmer and that science has learned the futility of its more dogmatic assumptions.[10]

The very growth of science is in fact a gradual recognition of motion as the basis of phenomena and an increasing comprehension of what may be called the laws of motion. When motion was regarded as simple and regular, it seemed possible to explain phenomena by correspondingly simple and regular laws; but when each primary motion was seen to be the resultant of an infinite series of motions the question became in like manner infinitely complex, or in other words insoluble. But to be clear we must consider the matter more in detail.