Thus did the different successive states of the human intellect, even at an early stage of its progress, overlap one another, the Fetichistic, the Polytheistic, and the Metaphysical modes of thought coexisting even in the same minds, while the belief in invariable laws, which constitutes the Positive mode of thought, was slowly winning its way beneath them all, as observation and experience disclosed in one class of phaenomena after another the laws to which they are really subject. It was this growth of positive knowledge which principally determined the next transition in the theological conception of the universe, from Polytheism to Monotheism.
It cannot be doubted that this transition took place very tardily. The conception of a unity in Nature, which would admit of attributing it to a single will, is far from being natural to man, and only finds admittance after a long period of discipline and preparation, the obvious appearances all pointing to the idea of a government by many conflicting principles. We know how high a degree both of material civilization and of moral and intellectual development preceded the conversion of the leading populations of the world to the belief in one God. The superficial observations by which Christian travellers have persuaded themselves that they found their own Monotheistic belief in some tribes of savages, have always been contradicted by more accurate knowledge: those who have read, for instance, Mr Kohl's Kitchigami, know what to think of the Great Spirit of the American Indians, who belongs to a well-defined system of Polytheism, interspersed with large remains of an original Fetichism. We have no wish to dispute the matter with those who believe that Monotheism was the primitive religion, transmitted to our race from its first parents in uninterrupted tradition. By their own acknowledgment, the tradition was lost by all the nations of the world except a small and peculiar people, in whom it was miraculously kept alive, but who were themselves continually lapsing from it, and in all the earlier parts of their history did not hold it at all in its full meaning, but admitted the real existence of other gods, though believing their own to be the most powerful, and to be the Creator of the world. A greater proof of the unnaturalness of Monotheism to the human mind before a certain period in its development, could not well be required. The highest form of Monotheism, Christianity, has persisted to the present time in giving partial satisfaction to the mental dispositions that lead to Polytheism, by admitting into its theology the thoroughly polytheistic conception of a devil. When Monotheism, after many centuries, made its way to the Greeks and Romans from the small corner of the world where it existed, we know how the notion of daemons facilitated its reception, by making it unnecessary for Christians to deny the existence of the gods previously believed in, it being sufficient to place them under the absolute power of the new God, as the gods of Olympus were already under that of Zeus, and as the local deities of all the subjugated nations had been subordinated by conquest to the divine patrons of the Roman State.
In whatever mode, natural or supernatural, we choose to account for the early Monotheism of the Hebrews, there can be no question that its reception by the Gentiles was only rendered possible by the slow preparation which the human mind had undergone from the philosophers. In the age of the Caesars nearly the whole educated and cultivated class had outgrown the polytheistic creed, and though individually liable to returns of the superstition of their childhood, were predisposed (such of them as did not reject all religion whatever) to the acknowledgment of one Supreme Providence. It is vain to object that Christianity did not find the majority of its early proselytes among the educated class: since, except in Palestine, its teachers and propagators were mainly of that class many of them, like St Paul, well versed in the mental culture of their time; and they had evidently found no intellectual obstacle to the new doctrine in their own minds. We must not be deceived by the recrudescence, at a much later date, of a metaphysical Paganism in the Alexandrian and other philosophical schools, provoked not by attachment to Polytheism, but by distaste for the political and social ascendancy of the Christian teachers. The fact was, that Monotheism had become congenial to the cultivated mind: and a belief which has gained the cultivated minds of any society, unless put down by force, is certain, sooner or later, to reach the multitude. Indeed the multitude itself had been prepared for it, as already hinted, by the more and more complete subordination of all other deities to the supremacy of Zeus; from which the step to a single Deity, surrounded by a host of angels, and keeping in recalcitrant subjection an army of devils, was by no means difficult.
By what means, then, had the cultivated minds of the Roman Empire been educated for Monotheism? By the growth of a practical feeling of the invariability of natural laws. Monotheism had a natural adaptation to this belief, while Polytheism naturally and necessarily conflicted with it. As men could not easily, and in fact never did, suppose that beings so powerful had their power absolutely restricted, each to its special department, the will of any divinity might always be frustrated by another: and unless all their wills were in complete harmony (which would itself be the most difficult to credit of all cases of invariability, and would require beyond anything else the ascendancy of a Supreme Deity) it was impossible that the course of any of the phaenomena under their government could be invariable. But if, on the contrary, all the phaenomena of the universe were under the exclusive and uncontrollable influence of a single will, it was an admissible supposition that this will might be always consistent with itself, and might choose to conduct each class of its operations in an invariable manner. In proportion, therefore, as the invariable laws of phaenomena revealed themselves to observers, the theory which ascribed them all to one will began to grow plausible; but must still have appeared improbable until it had come to seem likely that invariability was the common rule of all nature. The Greeks and Romans at the Christian era had reached a point of advancement at which this supposition had become probable. The admirable height to which geometry had already been carried, had familiarized the educated mind with the conception of laws absolutely invariable. The logical analysis of the intellectual processes by Aristotle had shown a similar uniformity of law in the realm of mind. In the concrete external world, the most imposing phaenomena, those of the heavenly bodies, which by their power over the imagination had done most to keep up the whole system of ideas connected with supernatural agency, had been ascertained to take place in so regular an order as to admit of being predicted with a precision which to the notions of those days must have appeared perfect. And though an equal degree of regularity had not been discerned in natural phaenomena generally, even the most empirical observation had ascertained so many cases of an uniformity almost complete, that inquiring minds were eagerly on the look-out for further indications pointing in the same direction; and vied with one another in the formation of theories which, though hypothetical and essentially premature, it was hoped would turn out to be correct representations of invariable laws governing large classes of phaenomena. When this hope and expectation became general, they were already a great encroachment on the original domain of the theological principle. Instead of the old conception, of events regulated from day to day by the unforeseen and changeable volitions of a legion of deities, it seemed more and more probable that all the phaenomena of the universe took place according to rules which must have been planned from the beginning; by which conception the function of the gods seemed to be limited to forming the plans, and setting the machinery in motion: their subsequent office appeared to be reduced to a sinecure, or if they continued to reign, it was in the manner of constitutional kings, bound by the laws to which they had previously given their assent. Accordingly, the pretension of philosophers to explain physical phaenomena by physical causes, or to predict their occurrence, was, up to a very late period of Polytheism, regarded as a sacrilegious insult to the gods. Anaxagoras was banished for it, Aristotle had to fly for his life, and the mere unfounded suspicion of it contributed greatly to the condemnation of Socrates. We are too well acquainted with this form of the religious sentiment even now, to have any difficulty in comprehending what must have been its violence then. It was inevitable that philosophers should be anxious to get rid of at least these gods, and so escape from the particular fables which stood immediately in their way; accepting a notion of divine government which harmonized better with the lessons they learnt from the study of nature, and a God concerning whom no mythos, as far as they knew, had yet been invented.