In fixing the relation of Plotinus to his own age, we have gone far towards fixing his relation to all ages, the place which he occupies in the development of philosophy as a connected whole. We have seen that as an attempt to discover the truth of things, his speculations are worthless and worse than worthless, since their method no less than their teaching is false. Nevertheless, Wisdom is justified of all her children. Without adding anything to the sum of positive knowledge, Plotinus produced an effect on men’s thoughts not unworthy of the great intellect and pure life which he devoted to the service of philosophy. No other thinker has ever accomplished a revolution so immediate, so comprehensive, and of such prolonged duration. He was the creator of Neo-Platonism, and Neo-Platonism simply annihilated every school of philosophy to which it was opposed. For thirteen centuries or more, the three great systems which had so long divided the suffrages of educated minds—Stoicism, Epicureanism, and Scepticism—ceased to exist, and were allowed to lapse into such complete oblivion that only a few fragments of the works in which they were originally embodied have been preserved. And Plotinus was enabled to do this by the profound insight which led him to strike less at any particular doctrine held by his opponents than at the common foundation on which they all stood, the materialism openly professed by the Stoics and Epicureans, and assumed by the Sceptics as the necessary presupposition of every dogmatic philosophy. It is true that the principle which he opposed to theirs was not of his own origination, although he stated it more powerfully than it had ever been stated before. But to have revived the spiritualism of Plato and Aristotle in such a way as to win for it universal acceptance, was precisely his greatest merit. It is also the only one that he would have claimed for himself. As we have already mentioned, he professed to be nothing more than the disciple of Plato. And although Aristotelian ideas abound in his writings, still not only are they overbalanced by the Platonic element, but Plotinus might justly have contended that they also belong, in a sense, to Plato, having been originally acquired by a simple development from his teaching.

We have said that the founder of Neo-Platonism contrived to blend the systems of his two great authorities in such a manner as to eliminate much of the relative truth which is contained in each of them taken by itself. It has been reserved for modern thought to accomplish the profounder synthesis which has eliminated their errors in combining their truths. Yet, perhaps, no other system would have satisfied the want of the time so well as that constructed by Plotinus out of the materials at his disposal. Such as it was, that system held its ground as the reigning philosophy until all independent thinking was suppressed by Justinian, somewhat more than two and a half centuries after its author’s death. Even then it did not become extinct, but reappeared in Christian literature, in the writings attributed to Dionysius the Areopagite, and again in the daring speculations of Erigena, the father of mediaeval philosophy, to pass under more diluted forms into the teaching of the later Schoolmen, until the time arrived for its renewed study in the original sources as an element of the Platonic revival in the fifteenth century. All this popularity proves, as we say, that Plotinus suited his own age and other ages which reproduced the same general intellectual tendencies. But the important thing was that he made Plato and Aristotle more interesting, and thus led men to study their writings more eagerly than before. The true reign of those philosophers does not begin until we reach the Middle Ages, and the commanding position which they then enjoyed was due, in great measure, to the revolution effected by Plotinus.

But when Neo-Platonism, as a literature and a system, had given way to the original authorities from which it was derived, its influence did not, on that account, cease to be felt. In particular, Plotinus gave currency to a certain interpretation of Plato’s teaching which has been universally accepted until a comparatively recent period, perhaps one may say until the time of Schleiermacher. We have seen how many elements of Platonism he left out of sight; and, thanks to his example, followed as it naturally was by Catholic theologians, the world was content to leave them out of sight as well. The charming disciple of Socrates whom we all know and love—the literary and dramatic artist, the brilliant parodist, the sceptical railleur from the shafts of whose irony even his own theories are not safe, the penetrating observer of human life, the far-seeing critic and reformer of social institutions—is a discovery of modern scholarship. Not as such did the master of idealism appear to Marsilio Ficino and Michael Angelo, to Lady Jane Grey and Cudworth and Henry More, to Berkeley and Hume and Thomas Taylor, to all the great English poets from Spenser to Shelley; not as such does he now appear to popular imagination; but as a mystical enthusiast, a dreamer of dreams which, whether they be realised or not in some far-off sphere, are, at any rate, out of relation to the world of sensuous experience and everyday life. So absolute, indeed, is the reaction from this view that we are in danger of rushing to the contrary extreme, of forgetting what elements of truth the Plotinian interpretation contained, and substituting for it an interpretation still more one-sided, still more inadequate to express the scope and splendour of Plato’s thoughts. Plato believed in truth and right and purity, believed in them still more profoundly than Plotinus; and his was a more effectual faith precisely because he did not share the sterile optimism of his Alexandrian disciple, but worked and watched for the realisation of what, as yet, had never been realised.[523]

Finally, by the form which he gave to Platonism, Plotinus has had a large share in determining the direction of modern metaphysics. Although, as we have seen, not, properly speaking, a pantheist himself, he showed how the ideal theory could be transformed into a pantheistic system, and pantheism it immediately became when the peculiar limitations and subtleties of Greek thought had ceased to dominate over the western mind, and when the restraints of Catholic orthodoxy had been removed or relaxed. The stream of tendency in this direction runs all through the Middle Ages, and acquires new volume and momentum at the Renaissance, until, by a process which will be analysed in the next chapter, it reaches its supreme expansion in the philosophy of Spinoza. Then, after a long pause, it is taken up by Kant’s successors, and combined with the subjective idealism of modern psychology, finally passing, through the intervention of Victor Cousin and Sir William Hamilton, into the philosophy of Mr. Herbert Spencer.

The last-named thinker would, no doubt, repudiate the title of pantheist; and it is certain that, under his treatment, pantheism has reverted, by a curious sort of atavism, to something much more nearly resembling the original doctrine of the Neo-Platonic school. Mr. Spencer tells us that the world is the manifestation of an unknowable Power. Plotinus said nearly the same, although not in such absolutely self-contradictory terms.[524] Mr. Spencer constantly assumes, by speaking of it in the singular number, that the creative Power of which we know nothing is one; having, apparently, convinced himself of its unity by two methods of reasoning. First, he identifies the transcendent cause of phenomena with the absolute, which is involved in our consciousness of relation; leaving it to be inferred that as relativity implies plurality, absoluteness must imply unity. And, secondly, from the mutual convertibility of the physical forces, he infers the unity of that which underlies force. Plotinus also arrives at the same result by two lines of argument, one à posteriori, and derived from the unity pervading all Nature; the other à priori, and derived from the fancied dependence of the Many on the One. Even in his use of the predicate Unknowable without a subject, Mr. Spencer has been anticipated by Damascius, one of the last Neo-Platonists, who speaks of the supreme principle as τὸ ἄγνωστον.[525] And the same philosopher anticipates the late Father Dalgairns in suggesting the very pertinent question, how, if we know nothing about the Unknowable, we know that it is unknowable.

Nor is this all. Besides the arguments from relativity and causation, Mr. Spencer has a third method for arriving at his absolute. He thinks away all the determinations imposed by consciousness on its objects, and identifies the residual substance with the ultimate reality of things. Now, this residue, as we have seen, exactly corresponds to the Matter, whether intelligible or sensible, of Aristotle and Plotinus. As such, it stands in extreme antithesis to the One, and yet there is a near kinship between them. Probably, according to Plotinus, and certainly according to Proclus,[526] Matter is a direct product of the One, whose infinite power it reflects. All existence is formed by the union, in varying proportions, of these two principles. Above all, both are unknowable. Thus it was natural that in the hands of less subtle analysts than the Greeks they should coalesce into a single substance. And, as a matter of fact, they have so coalesced in the systems of Giordano Bruno, of Spinoza, and finally of Mr. Spencer.

Here we imagine an impatient reader exclaiming, ‘How can Mr. Herbert Spencer, who knows, if possible, even less of Greek philosophy than of his own Unknowable, have derived that principle from the Greeks?’ Well, we have already traced the genealogy by which the two systems of agnosticism are connected. And some additional light will be thrown on the question if we consider that the form of Neo-Platonism was largely determined by the manner in which Plotinus brought the spiritualistic conceptualism of Plato and Aristotle into contact with the dynamic materialism of the Stoics; and that the form of Mr. Spencer’s philosophy has been similarly determined by bringing the idealism of modern German thought into contact with the mechanical evolutionism of modern science. Thus, under the influence of old associations, has pantheism been metamorphosed into a crude agnosticism, which faithfully reproduces the likeness of its original ancestors, the Plotinian Matter and the Plotinian One.

XII.[527]

The history of Neo-Platonism, subsequently to the death of Plotinus, decomposes itself into several distinct tendencies, pursuing more or less divergent lines of direction. First of all, it was drawn into the supernaturalist movement against which it had originally been, in part at least, a reaction and a protest. One sees from the life of its founder how far his two favourite disciples, Amelius and Porphyry, were from sharing his superiority to the superstitions of the age. Both had been educated under Pythagorean influences, which were fostered rather than repressed by the new philosophy. With Porphyry, theoretical interests are, to a great extent, superseded by practical interests; and, in practice, the religious and ascetic predominates over the purely ethical element. Still, however great may have been his aberrations, they never went beyond the limits of Hellenic tradition. Although of Syrian extraction, his attitude towards Oriental superstition was one of uncompromising hostility; and in writing against Christianity, his criticism of the Old Testament seems to have closely resembled that of modern rationalism. But with Porphyry’s disciple, Iamblichus, every restraint is thrown aside, the wildest Oriental fancies are accepted as articles of belief, and the most senseless devotional practices are inculcated as means towards the attainment of a truly spiritual life.

Besides the general religious movement which had long been in action, and was daily gaining strength from the increasing barbarisation of the empire, there was, at this juncture, a particular cause tending to bring Greek philosophy into close alliance with the mythology which it had formerly rejected and denounced. This was the rapid rise and spread of Christianity. St Augustine has said that of all heathen philosophers none came nearer to the Christian faith than the Neo-Platonists.[528] Nevertheless, it was in them that the old religion found its only apologists and the new religion its most active assailants. We have already alluded to the elaborate polemic of Porphyry. Half a century later, the same principles could boast of a still more illustrious champion. The emperor Julian was imbued with the doctrines of Neo-Platonism, and was won back to the ancient faith by the teaching of its professors.