In criticising the Stoic system as a whole, the New Academy and the later Sceptics had incidentally dwelt on sundry absurdities which followed from the materialistic interpretation of knowledge; and Plotinus evidently derived some of his most forcible objections from their writings; but no previous philosopher that we know of had set forth the whole case for spiritualism and against materialism with such telling effect. And what is, perhaps, more important than any originality in detail, is the profound insight shown in choosing this whole question of spiritualism versus materialism for the ground whereon the combined forces of Plato and Aristotle were to fight their first battle against the naturalistic system which had triumphed over them five centuries before. It was on dialectical and ethical grounds that the controversy between Porch and Academy, on ethical and religious grounds that the controversy between Epicureanism and all other schools of philosophy, had hitherto been conducted. Cicero and Plutarch never allude to their opponents as materialists. Only once, in his polemic against Colôtes, does Plutarch observe that neither a soul nor anything else could be made out of atoms, but this is because they are discrete, not because they are extended.[446] For the rest, his method is to trip up his opponents by pointing out their inconsistencies, rather than to cut the ground from under their feet by proving that their theory of the universe is wrong.
Under such guidance as this. Platonism had made but little way. We saw, in the concluding sections of the last chapter and in the opening section of the present chapter, that it profited by the religious and literary revival of the second century, just as it was to profit long afterwards by the greater revival of the fifteenth century, so much so as to become the fashionable philosophy of the age. Yet, even in that period of its renewed splendour, the noblest of contemporary thinkers was not a Platonist but a Stoic; and although it would be unfair to measure the moral distance between the Porch and the Academy by the interval which separates an Aurelius from an Apuleius, still it would seem as if naturalism continued to be the chosen creed of strenuous and dutiful endeavour, while spiritualism was drifting into an alliance with hysterical and sensuous superstition. If we may judge by the points which Sextus Empiricus selects for controversial treatment, Stoicism was still the reigning system in his time, that is to say, about the beginning of the third century; and if, a generation later, it had sunk into neglect, every rival school, except that of Epicurus, was in exactly the same condition. Thus the only advance made was to substitute one form of materialism for another, until Neo-Platonism came and put an end to their disputes by destroying the common foundation on which they stood; while, at the same time, it supplied a completely organised doctrine round which the nobler elements of the Hellenic revival could rally for a last stand against the foes that were threatening it from every side.
VI.
We have seen how Plotinus establishes the spiritualistic basis of his philosophy. We have now to see how he works out from it in all directions, developing the results of his previous enquiries into a complete metaphysical system. It will have been observed that the whole method of reasoning by which materialism was overthrown, rested on the antithesis between the unity of consciousness and the divisibility of corporeal substance. Very much the same method was afterwards employed by Cartesianism to demonstrate the same conclusion. But with Descartes and his followers, the opposition between soul and body was absolute, the former being defined as pure thought, the latter as pure extension. Hence the extreme difficulty which they experienced in accounting for the evident connexion between the two. The spiritualism of Plotinus did not involve any such impassable chasm between consciousness and its object. According to him, although the soul is contained in or depends on an absolutely self-identical unity, she is not herself that unity, but in some degree shares the characters of divisibility and extension.[447] If we conceive all existence as bounded at either extremity by two principles, the one extended and the other inextended, then soul will still stand midway between them; not divided in herself, but divided in respect to the bodies which she animates. Plotinus holds that such an assumption is necessitated by the facts of sensation. A feeling of pain, for example, is located in a particular point of the body, and is, at the same time, apprehended as my feeling, not as some one else’s. A similar synthesis obtains through the whole of Nature. The visible universe consists of many heterogeneous parts, held together by a single animating principle. And we can trace the same qualities and figures through a multitude of concrete individuals, their essential unity remaining unbroken, notwithstanding the dispersion of the objects in which they inhere.
Here Plotinus avowedly follows the teaching of Plato, who, in the Timaeus, describes Being or Substance as composed by mingling the indivisible and unchanging with the divisible and corporeal principle.[448] And, although there is no express reference, we know that in placing soul between the two, he was equally following Plato. It is otherwise in the next essay, which undertakes to give a more explicit analysis of psychical phenomena.[449] The soul, we are told, consists, like external objects, of two elements related to one another as Form and Matter. These are reason and sense. The office of the former is, primarily, to enlighten and control the latter. Plato had already pointed to such a distinction; but Aristotle was the first to work it out clearly, and to make it the hinge of his whole system. It is, accordingly, under the guidance of Aristotle that Plotinus proceeds in what he has next to say. Just as there is a soul of the world corresponding to our soul, so also, he argues, there must be a universal objective Reason outside and above the world. In speaking of this Reason, we shall, for clearness’ sake, in general call it by its Greek name, Nous. Nous, according to Aristotle, is the faculty by which we apprehend abstract ideas; it is self-thinking thought; and, as such, it is the prime mover of Nature. Plotinus adopts the first two positions unreservedly, and the third to a certain extent; while he brings all three into combination with the Platonic theory of ideas. It had always been an insuperable difficulty in the way of Plato’s teaching that it necessitated, or seemed to necessitate, the unintelligible notion of ideas existing without any mind to think them. For a disciple of Aristotle, the difficulty ceases to exist if the archetypal essences assumed by Plato are conceived as residing in an eternal Nous. But, on the other hand, how are we to reconcile such an accommodation with Aristotle’s principle, that the Supreme Intelligence can think nothing but itself? Simply by generalising from the same master’s doctrine that the human Nous is identical with the ideas which it contemplates. Thought and its object are everywhere one. Thus, according to Plotinus, the absolute Nous embraces the totality of archetypes or forms which we see reflected and embodied in the material universe. In thinking them, it thinks itself, not passing from one to the other as in discursive reasoning, nor bringing them into existence by the act of thought, but apprehending them as simultaneously present realities.
To explain how the Nous could be identical with a number of distinct ideas was a difficult problem. We shall have to show at a more advanced stage of our exposition how Plotinus endeavoured to solve it with the help of Plato’s Sophist. In the essay where his theory is first put forward, he cuts the knot by asserting that each idea virtually contains every other, while each in its actual and separate existence is, so to speak, an independent Nous. But correlation is not identity; and to say that each idea thinks itself is not to explain how the same subject can think, and in thinking be identical with all. The personal identity of the thinking subject still stands in unreconciled opposition to the multitude of thoughts which it entertains, whether successively or in a single intuition. Of two things one: either the unity of the Nous or the diversity of its ideas must be sacrificed. Plotinus evades the alternative by a kind of three-card trick. Sometimes his ideal unity is to be found under the notion of convergence to a common centre, sometimes under the notion of participation in a common property, sometimes under the notion of mutual equivalence.
The confusion was partly inherited from Aristotle. When discussing the psychology of that philosopher, we showed that his active Nous is no other than the idea of which we are at any moment actually conscious. Our own reason is the passive Nous, whose identity is lost in the multiplicity of objects with which it becomes identified in turn. But Aristotle was careful not to let the personality of God, or the supreme Nous, be endangered by resolving it into the totality of substantial forms which constitute Nature. God is self-conscious in the strictest sense. He thinks nothing but himself. Again, the subjective starting-point of Plotinus may have affected his conception of the universal Nous. A single individual may isolate himself from his fellows in so far as he is a sentient being; he cannot do so in so far as he is a rational being. His reason always addresses itself to the reason of some one else—a fact nowhere brought out so clearly as in the dialectic philosophy of Socrates and Plato. Then, when an agreement has been established, their minds, before so sharply divided, seem to be, after all, only different personifications of the same universal spirit. Hence reason, no less than its objects, comes to be conceived as both many and one. And this synthesis of contradictories meets us in modern German as well as in ancient Greek philosophy.
After his preliminary analysis of Nous, we find Plotinus working out in two directions from the conception so obtained.[450] He begins by explaining in what relation the human soul stands to the universal reason. To him, personally, it seemed as if the world of thought into which he penetrated by reflecting on his own inmost essence, was so much the real home of his soul that her presence in a bodily habitation presented itself as a difficulty requiring to be cleared up. In this connexion, he refers to the opinions of the Pythagoreans, who looked on our earthly life as an unmixed evil, a punishment for some sin committed in a former stage of existence. Their views seem to have been partly shared by Plato. Sometimes he calls the body a prison and a tomb into which the soul has fallen from her original abode. Yet, in his Timaeus, he glorifies the visible world, and tells us that the universal soul was divinely appointed to give it life and reason; while our individual souls have also their part to play in perfecting the same providential scheme.
It is to the second theory that Plotinus evidently leans. However closely his life may have been conformed to the Pythagorean model—a point with respect to which we have nothing better than the very prejudiced statements of Porphyry to rely on—there is no trace of Pythagorean asceticism in his writings. Hereafter we shall see how hostile he was to Gnostic pessimism. In the preceding essay, he had already specified admiration for physical beauty as a first and necessary step in the soul’s ascent to a contemplation of spiritual realities;[451] and now it is under the guidance of Plato’s later speculations that he proceeds to account for her descent from that higher world to the restraints of matter and of sense.
With regard to the universal soul of Nature, there is, indeed, no difficulty at all. In giving a sensible realisation to the noetic ideas, she suffers no degradation or pollution by contact with the lower elements of matter. Enthroned on the outer verge of the cosmos, she governs the whole course of Nature by a simple exercise of volition, and in the enjoyment of a felicity which remains undisturbed by passion or desire. But just as we have seen the supreme Nous resolving itself into a multitude of individual intelligences, so also does the cosmic soul produce many lesser or partial souls of which our own is one. Now these derivative souls cannot all be equal, for that would be to defeat the purpose of creation, which is to realise all the possibilities of creation from the highest to the lowest. Thus each has an office corresponding to her place in the scale of perfection.[452] We may say of the human soul that she stoops to conquer. Her mission is to cope with the more recalcitrant forms of matter. It is to the struggle with their impurities that the troubles and passions of our life are due. By yielding to earthly temptations, we suffer a second fall, and one much more real than the first; by overcoming them, as is perfectly in our power to do, we give scope and exercise to faculties which would otherwise have remained dormant and unknown. Moreover, our soul retains the privilege of returning to her former abode, enriched by the experience acquired in this world, and with that clearer perception of good which the knowledge of its opposite alone can supply. Nay, paradoxical as the assertion may seem, she has not entirely descended to earth, but remains in partial communication with the noetic world by virtue of her reasoning faculty; that is to say, when its intuitions are not darkened and disturbed by the triumph of sensuous impressions over the lower soul. On this and on many other occasions, Plotinus betrays a glimmering consciousness that his philosophy is purely subjective, and that its attempted transcendentalism is, in truth, a projection of psychological distinctions into the external world. Starting with the familiar division of human nature into body, soul, and spirit (or reason), he endeavours to find an objective counterpart for each. Body is represented by the material universe, soul by the animating principle of Nature, reason by the extramundane Nous. Under these three heads is comprised the totality of real existence; but existence itself has to be accounted for by a principle lying above and beyond it, which has still to be obtained by an effort of abstraction from the data that self-consciousness supplies.[453]