In the course of what we may term the Alexandrian period the Platonic school had steadily taken the first place. It was indeed considerably changed from the ancient Academic standards, chiefly by the introduction of semi-mystical elements which were attributed to Pythagoras, and later by fusion with the neo-Aristotelian school. The Pythagorean elements probably can be traced ultimately to an Indian source, at least in such instances as the doctrine of the unreality of matter and phenomena which appears in Indian philosophy as māyā, and the re-incarnation of souls which is avatar. The tendency of native Greek thought, as seen in Democritus and other genuinely Greek thinkers, was distinctly materialistic, but Plato apparently incorporates some alien matter, probably Indian, perhaps some Egyptian ideas as well. We know there was a transmission of oriental thought influencing Hellenism, but very little is known of the details. Certainly Plotinus and the neo-Platonists were eclectic thinkers and drew freely from oriental sources, some disguised as Pythagorean, by a long sojourn in Greek lands.
In the 3rd century A.D. we find the beginnings of what is known as neo-Platonism. A very typical passage in Gibbon’s Decline and Fall (ch. xiii.) refers to the neo-Platonists as “men of profound thought and intense application; but, by mistaking the true object of philosophy, their labours contributed much less to improve than to corrupt the human understanding. The knowledge that is suited to our situation and powers, the whole compass of moral, natural, and mathematical science, was neglected by the new Platonists; whilst they exhausted their strength in the verbal disputes of metaphysics, attempted to explore the secrets of the invisible world, and studied to reconcile Aristotle with Plato, on subjects of which both these philosophers were as ignorant as the rest of mankind.” Although this passage is coloured by some of the peculiar prejudices of Gibbon it fairly represents a common attitude towards neo-Platonism and might equally apply to every religious movement the world has ever seen.
The neo-Platonists were the result, we may say the inevitable result, of tendencies which had been at work ever since the age of Alexander and the widening of the mental horizon and the decay of interest in the old civic life. The older philosophers had endeavoured to produce efficient citizens; but under imperialist conditions efficient citizens were not so much wanted as obedient subjects. Through all this period there are very clear indications of the new trend of thought which assumes a more theological and philanthropic character, aiming at producing good men rather than useful citizens. The speculations of Philo the Jewish Platonist give very plain indications of these new tendencies as they appeared in Alexandria. He shows the monotheistic tendency which was indeed present in the older philosophers but now begins to be more strongly emphasized as philosophy becomes more theological in its speculations, though no doubt in his case this was largely due to the religion he professed. He expressed the doctrine of a One God, eternal, unchanging, and passionless, far removed above the world of phenomena, as the First Cause of all that exists, a philosophical monotheism which can be fitted in with the Old Testament but does not naturally proceed from it. The doctrine of an Absolute Reality as the necessary cause of all that is variable, something like the fulcrum which Archimedes needed to move the world, was one to which all philosophy, and especially the Platonic school, was tending. But, as causation to some extent implies change, this First Cause could not be regarded as directly creating the world, but only as the eternal source of an eternally proceeding emanation by means of which the power of the First Cause is projected so as to produce the universe and all it contains. The essential features of this teaching are, the absolute unity of the First Cause, its absolute reality, its eternity, and its invariability, all of which necessarily removes it above the plane of things knowable to man; and the operative emanation ceaselessly issuing forth, eternal like its source, yet acting in time and space, an emanation which Philo terms the Logos or “Word.” Although these theories are to a large extent only an expression of logical conclusions towards which the Platonists were then advancing, Philo had curiously little influence. No doubt there was a tendency to regard his teaching as mainly an attempt to read a Platonic meaning into Jewish doctrine, and certainly the large amount of attention he devoted to exegesis of the Old Testament and to Jewish apologetics would prevent his works from receiving serious attention from non-Jewish readers. Again, although his ideas about monotheism and the nature of God were those to which Platonism was tending, they represent also a Jewish attitude which, starting from a monotheistic stand-point was then, under Hellenistic influence, making towards a supra-sensual idea of God, explaining away the anthropomorphisms of the Old Testament and postulating an emanation, the Hochma or “wisdom” of God as the intermediary in creation and revelation. Undoubtedly Philo, or the Philonic school of Hellenistic Judaism, was responsible for the Logos doctrine which appears in the portions of the New Testament bearing the name of St. John. He had an influence also on Jewish thought as appears in the Targums where the operative emanation which proceeds from the First Cause is no longer the “wisdom” of God but the “Word.” He seems to have had no influence at all on the course of Alexandrian philosophy generally.
The tendencies which were at work in Philo were also leavening Greek thought outside Jewish circles and all schools of philosophy show a growing definiteness in their assertion of One God eternal and invariable, as the source and First Cause of the universe. It is a recognition of the principal of uniformity in nature and of the necessity of accounting for the cause of this uniformity. The Gnostic sects, which were of philosophical origin, simply show the definite acceptance of this First Cause and, having accepted it as on a plane far removed above imperfection and variation, suggest intermediary emanations as explaining the production of an imperfect and variable universe from a primary source which is itself perfect and unchanging. The descriptive accounts of the successive emanations, each less perfect than that from which it proceeds, which ultimately produced the world in which we perceive phenomena, are different in different Gnostic systems, often crude enough and grotesque in our eyes, and frequently drawing from Christianity or Judaism or some other of the oriental religions which were then attracting the attention of the Roman world. But these details are of minor importance. All Gnostic theories bear witness to the belief that there is a First Cause, absolutely real, perfect, eternal, and far removed above this world of time and space, and that some emanation or emanations must have intervened to connect the resultant world, such as we know it, with this sublime Cause: and such belief indicates in crude form a general conviction which was getting hold of all current thought in the early centuries of the Christian era.
Complementary to this was the psychological teaching represented by the Aristotelian commentator Alexander of Aphrodisias who taught at Athens, A.D. 198-211. His extant works include commentaries on the first book of the Analytica Priora, on the Topica, Meteorology, de sensu, the first five books of the Metaphysics and an abridgment of the other books of the Metaphysics, as well as treatises on the soul, etc. Over and over again his treatise on the soul and his commentaries are translated into Arabic, paraphrased, and made the subject of further commentaries, until it seems that his psychology is the very nucleus of all Arabic philosophy, and it is this which forms the main point of the Arabic influence on Latin scholasticism. It becomes indeed absolutely essential that we understand the Alexandrian interpretation of the Aristotelian psychology if we are to follow the oriental development of Greek science.
The first point is to understand what is to be implied in the term “soul.” Plato was really a dualist in that he regards the soul as a separate entity which animates the body and compares it to a rider directing and controlling the horse he rides. But Aristotle makes a more careful analysis of psychological phenomena. In the treatise de anima he says “there is no need to enquire whether soul and body are one, any more than whether the wax and the imprint are one; or, in general, whether the matter of a thing is the same with that of which it is the matter.” (Aristot: de anima. II. i. 412. b. 6.) Aristotle defines the soul as “the first actuality of a natural body having in it the capacity of life” (id. 412. b. 5), in which “first” denotes that the soul is the primary form by which the substance of the body is actualized, and “actuality” refers to the actualizing principle by which form is given to the body which otherwise would be only a collection of separate parts each having its own form but the aggregate being without corporate unity until the soul gives it form; in this sense the soul is the realization of the body (cf. Aristot: Metaph. iii. 1043. a. 35). A dead body lacks this actualizing and centralizing force and is only a collection of limbs and organs, yet even so it is not an artificial collection such as a man might put together, but “a natural body having in it the capacity of life,” that is to say, an organic structure designed for a soul which is the cause or reason of its existence and which alone enables the body to realize its object.
The soul contains four different faculties or powers which are not strictly to be taken as “parts” though in the passage cited above Aristotle uses the term “parts.” These are, (i) the nutritive, the power of life whereby the body performs such functions as absorbing nourishment, propagating its species, and other functions common to all living beings, whether animal or vegetable: (ii) the sensible, by which the body obtains knowledge through the medium of the special senses of sight, hearing, touch, etc., and also the “common sense” by means of which these perceptions are combined, compared, and contrasted so that general ideas are obtained which ultimately rest on the sense perceptions: (iii) the locomotive, which prompts to action, as desire, appetite, will, etc., also based, though indirectly, on sense perception, being suggested by memories of senses already in action: (iv) the intellect or pure reason, which is concerned with abstract thought and is not based on sense perception. All these, embracing life in its widest application, are classed together as soul, but the last, the intellect, nous, or rational soul, is peculiar to man alone. It does not depend on the senses, directly or indirectly, and so, whilst the other three faculties necessarily cease to function when the bodily organs of sense cease, it does not necessarily follow that this rational soul will cease as it is apparently independent of the organ sense. This nous or “spirit” is reduced by Aristotle to a much more restricted range than is usual in the older philosophers and is taken to mean that which has the capacity of abstract knowledge, independent of the information due, directly or indirectly, to sense perception. It would seem, however, to be a distinct species of faculty for Aristotle says: “As regards intellect and the speculative faculty the case is not yet clear. It would seem, however, to be a distinct species of soul, and it alone is capable of separation from the body, as that which is eternal from that which is perishable. The remaining parts of the soul are, as the foregoing consideration shows, not separable in the way that some allege them to be: at the same time it is clear that they are logically distinct.” (Arist. de anima. II. ii. 413. b. 9). It is suggested that (i) the rational soul is of a distinct species and so presumably derived from a different source than the other faculties of the soul, but nothing is said as to whence it is derived: (ii) it is capable of existence independently of the body, that is to say its activity does not depend on the operation of the bodily organs, but it is not stated that it does so exist; (iii) it is eternal on the ground that it can exist apart from the perishable.
The obscurity of this statement has led to a great divergence in its treatment by commentators. Theophrastus offers cautious suggestions and evidently regards the rational soul as differing only in degree of evolution from the lower forms of soul faculty. It was Alexander of Aphrodisias who opened up new fields of speculation, distinguishing between a material intellect and an active intellect. The former is a faculty of the individual soul and this it is which is the form of the body, but it means no more than the capacity for thinking and is of the same source as the other faculties of the human soul. The active intellect is not a part of the soul but is a power which enters it from outside and arouses the material intellect to activity; it is not only different in source from the material soul, but different in character in that it is eternal and so always has been and always will be, its rational power existing quite apart from the soul in which the thinking takes place; there is but one such substance and this must be identified with the deity who is the First Cause of all motion and activity, so that the active intellect is pictured as an emanation from the deity entering the human soul, arousing it to the exercise of its higher functions, and then returning to its divine source. This theistic interpretation of Aristotle was strongly opposed by the commentator Themistius who considers that Alexander forces the statement of the text out of its natural meaning and draws an unwarrantable deduction from the two sentences “these differences must be present in the soul,” and “this alone is immortal and eternal.” It seems, however, that Alexander’s interpretation played an important part in the formation of neo-Platonic theory, and it certainly is the key to the history of Muslim philosophy, and is not without its importance in the development of Christian mysticism.
The neo-Platonic school was founded by Ammonius Saccas, but really takes its definite form under Plotinus (d. 269 A.D.). In sketching in brief outline the leading principles of this system we shall confine ourselves to the last three books of the Enneads (iv-vi) as these, in the abridged form known as the “Theology of Aristotle” formed the main statement of neo-Platonic doctrine known to the Muslim world. In the teaching of Plotinus God is the Absolute, the First Potency (Enn. 5. 4. 1.), beyond the sphere of existence (id. 5. 4. 2.), and beyond reality, that is to say, all that we know as existence and being is inapplicable to him, and he is therefore unknowable, because on a plane which is altogether beyond our thought. He is unlimited and infinite (id. 6. 5. 9.) and consequently One, as infinity excludes the possibility of any other than himself on the same plane of being. Yet Plotinus does not allow the numeral “one” to be applied to God as numerals are understandable and refer to the plane of existence in which we have our being, so that “one” as a mere number is not attributed to God, but rather singularity in the sense of an exclusion of all comparison or of any other than himself. As Absolute God implies a compelling necessity so that all which proceeds from him is not enforced but is necessarily so in the sense that nothing else is possible; thus, for example, it results from him that two sides of a triangle are greater than the third side, they are not forced into greater length, but in the nature of things must be so, and this necessary nature has its compelling source in the First Cause. Yet Plotinus will not allow us to say that God “wills” anything, for will implies a desire for what is not possessed or is not yet present (id. 5. 3. 12); will operates in time and space, but necessity has for ever proceeded from the Eternal One who does not act in time. Nor can we conceive God as knowing, conscious, or thinking, all terms which describe our mental activities in the world of variable phenomena; he is all-knowing by immediate apprehension ([Greek: athroa epibolê] ἀθρόα ἐπιβολή) which in no way resembles the operation of thought but is superconscious, a condition which Plotinus describes as “wakefulness” ([Greek: egrêgorsis] ἐγρήγορσις), a perpetual being aware without the need of obtaining information.
From the true God, the eternal Absolute, proceeds the nous, a term which has been variously rendered as Reason, Intellect, Intelligence, or Spirit, this last being the term which Dr. Inge regards as the best expression (Inge: Plotinus. ii. p. 38), and this nous is fairly equivalent to the Philonic and Christian Logos. An external emanation is necessitated in order that the First Cause may remain unchanged which would not be the case if it had once not been a source and then had become the source of emanation; there can be no “becoming” in the First Cause. The emanation is of the same nature as its cause, but is projected into the world of phenomena. It is self-existent, eternal, and perfect, and comprehends within itself the “spirit world,” the objects of abstract reason, the whole of the reality which lies behind the world of phenomena; the things perceived are only the shadows of these real ones. It perceives, not as seeking and finding, but as already possessing (id. 5. 1. 4.), and the things perceived are not separate or external but as included and apprehended by immediate intuition (id. 5. 2. 2.)