In all this advance, moreover, we find that the process illustrated by the changing phases of man's mental attitude toward Nature also holds good of the multifarious acts by which, in what is known as religion, man has sought to realize that attitude in conduct. For, in seeking to adjust himself to the system of Power, man has been forced to conceive of his Pantheon in terms as well of his social arrangements as of the political system under which he happened to be living. The spirit world of a horde of savages could only reflect the indefiniteness and disunion of the nomads whose imagination it satisfied. But as the household made its appearance, as a definite social structure arose, and the straggling tribes began to be united into nations, the gods themselves took on the characters of an analogous transformation. The divine selfishness—the "remota ab nostris rebus"—long ago satirized by the poet Lucretius, obviously correlated with the attitude of man toward man, just as naturally gave way, with the growth of the social sympathies, to the thought of that more active concern in human affairs which is one of the salient characters of the later phases of monotheism. The original indifference of Deity toward ethical issues—a widespread feature of the earlier religious conceptions—could not but pass away with the moral stagnation of the ancient communities out of which it had arisen. So the comparatively new thought of a God definitely identified in his aims and activities with the cause of moral reform is no less obviously a result of the new attitude of man himself toward problems of social improvement; while the persistence with which, in human thought, morals remain associated with religion sufficiently illustrates the extent to which man's view of each has been determined by the self-knowledge which underlies his attitude toward both. Note also, finally, the manifest relation in which our human thought regarding mind and body has always stood toward conceptions of a world-soul, and then the dependence of man's view of the relation of God to the world upon the knowledge of his own planet and of its place in the universe. For as long as our ancestor held the old geocentric theory of the cosmos—regarded the heavens as a set of spheres revolving around a flat earth—the thought of a deity outside the world related to it as a mechanician might be to a cunningly devised piece of clockwork which he had brought into existence, was inevitable. But when the geographical discoveries of the fifteenth century co-operated with the revelations of Galilei to secure the final triumph of the Copernican over the Ptolemaic theory of the world-order, the ancient view of Deity as external to his creation gave place to the essentially modern conception of his immanence.
If now we attentively examine the progress above described, we shall find that the earliest attitude of the human mind toward the external system tends in the latest to repeat itself on a higher plane and with a richer content. Thus vitalism, by the process of unification and intensification, culminates in anthropomorphic monotheism, while animism, through the coalescence of objects and forces at first believed to be separately animated, finally develops into pantheism. These two lines of thought, moreover, tend themselves to converge, or, at any rate, to become interchangeable, since monotheism, by deanthropomorphizing itself, approximates to pantheism, as is well seen in the Christian theologies and ethical religions of the world; while pantheism, by emphasizing the characters of intelligence and will, is sometimes hardly to be distinguished from those modern forms of monotheism which teach the doctrine of immanence. The intellectual outcome of the whole movement, embodying the modern attitude in Nature philosophy, is thus no longer anthropomorphism, but psychomorphism, since it reads into the universe, not the characters which distinguish human beings from the lower animals, but the highest manifestation of the characters recognized to be common to both, namely, psychic characters—the characters, in a word, of mind. For the deepest reaches of human thought, the process of man-likening has thus given way to the process of mind-likening. On the subjective side of mental inquiry we get psychomorphic monotheism, or what may be called theological pantheism; while on the objective side we reach scientific pantheism, or monism. It is true that the psychomorphism of scientific monism is reached by a process different from that which has culminated in the mind-likening of theological pantheism. Yet in both cases there is the same projection of intelligence into the external system as a means of comprehending it. And as the intelligence of atoms implies their vitality, we really return in scientific monism to the vitalistic attitude of the primitive observer of Nature. The salient difference between the two views is this: that while early man subsumed under his concept of vitality only the rudest characters thereof, the terms in the mind of the monist connotes in all their richness the ideas associated with mind.
Enough has now been said to show the basis on which rests the whole superstructure, of man's mental attitude toward the cosmos. Despite all uncertainties regarding the details of the process, we may be assured of its fundamental nature, and are thus compelled to recognize the dependence of the forms of man's mental attitude toward the universe upon his knowledge of himself. It is because his own actions have their source in a personal will that he refers external movements to will. He is conscious of his own acts, and the world around him can not be devoid of a like illumination. Does he himself plan? Nature must also be intelligent. And the highest qualities which he can discover in himself he reads unhesitatingly into the cosmos.
At first sight, then, knowledge may seem inextricably involved in the process here described. If man can not know the external system to which he must adapt himself save by assimilating it to himself—save by interpreting it on the basis of analogies which he discovers between his own body and its activities, and the world with its activities—are we not committed by our very nature as organisms to all the errors which that nature imposes upon us? If, in other words, every effort to view the universe as it is, independently of us, be rendered impossible by the very nature of the knowing process, with what chance of success shall we seek to eliminate those vitalistic and psychomorphic characters which seem to belong to that process as its very warp and woof? In reality our knowledge inflicts upon us no such dilemma. Man is the helpless "measure of the universe" only to the extent that his reasoning processes are undeveloped. That knowledge must always have a subjective element is undoubted, but that man must always mistake the subjective vesture with which things are clothed by the senses for the things themselves is an inference which the whole history of thought negatives. While his life remained simple, primitive man could regard appearances as realities without prejudicing the overplus of utility brought to him by his knowledge. Yet as his relation to the natural surroundings grew in complexity, the importance of the reasoning process, with its veto power over the deliverances of the senses, began to assert itself. At first accepted with little or no demur, these deliverances came more and more to be challenged in the interest of self-maintenance; and finally, by expansion of a germ possessed by the mind in the beginning, there was developed that way of dealing with the testimony of appearances which we call the objective method. The evidence previously accepted had been, though on the whole useful, in large measure misleading. For in appearances men saw and felt mainly what Nature was for them, and only to a minor degree what the external world was for and in itself. The great need of the investigator of Nature is to know what things are independently of man, in order to know how they act on one another, as a means of knowing how they will act on the human organism, and how that organism may react on them in the interest of its own life. The prejudice done by implicit reliance on sense testimony arose out of the fact that it presented objects as largely unrelated to each other—as so much being, rather than as so much doing, acting and interacting, determining and interdetermining. It became the function of reason to develop, out of the material furnished by the senses, a knowledge of the true nature of the system external to man and involving him in its scope which we call universe. In the carrying out of this function the analogical process has remained, but the analogies utilized, from being likenesses between what things seem to be to the senses, have more and more become analogies between propositions made regarding what things do, regarding how things act upon, are related to and determine each other.
Our knowledge of Nature, therefore, illustrates progress from a stage in which external objects are viewed as so much doing—from a stage in which they seem more or less isolated, more or less independent of each other—to a stage in which we know them as acting and interacting, and therefore, by virtue of this action and interaction, as interrelated and interdependent. It was because man had to begin with the thought of the world around him as a series of unconnected aspects that he fell into the error of regarding every object as containing within itself the powers which it put forth; it was by gradually progressing to the knowledge of the external system as a process that he discovered how inextricably the smallest "flower in the crannied wall" is linked to its vastest environment, and how dependent must be the mechanism of the molecule, as well as of the solar system, upon the whole universe Power which we call cosmos.
Thus also is it with man's method of interpreting the external world system. At first unable to fully perceive his own relation to that system, as part of his inability to perceive general cosmic relations, and therefore viewing himself as more or less independent of Nature—as something imposed upon it rather than as something arising out of it—he naturally sought to force it for purposes of explanation into the narrow limits of his knowledge of himself, of his feelings, his thoughts, his institutions. But as he grew in the power to comprehend his place in the system of things—to understand the way in which the objects and forces of the world were related to each other, together with the way in which he, as knowing organism, was related to the universe—he gradually ceased from his vain striving to subject the cosmos to himself, and at last learned not only to subordinate himself to the cosmos, but to trace to it unreservedly the whole method and meaning of his origin as a living, thinking organism. Man in the beginning could be no more than the measure of the universe. That he has come at last, wielding the objective method, to be its measurer, is the culmination of a struggle between false and true ways of interpreting Nature which has had the whole history of human thought for its arena, and for its final triumph the establishment of the objective or scientific method of investigation upon impregnable foundations.