By John K Hammelton
Plotinus is thought of as the father of Neo-Platonism, that period of time  during the third century AD when Plato's thought was enjoying a revival of
interest due to the growth of Christianity. Plotinus was born in Egypt about AD 204. He became impassioned for philosophy at the age of twenty-eight, and sought out the most highly reputed professors to be found at Alexandria. He always came away saddened and discouraged until a friend suggested the
philosopher Ammonius Saccas. Plotinus attended a lecture given by Ammonius, and explained to his comrade: "This was the man I was looking for." Plotinus studied for eleven years under Ammonius until he became eager to investigate the Persian methods and the system adopted among the people of the Indias.He joined Emperor Gordian's expedition against the Persians, but when Gordian lost his life Plotinus escaped to Antioch. At forty he settled in Rome where he lived and taught the rest of his life. He passed over in his sixty-sixth year proclaiming that he was striving to give back the divine in himself to the divine in the cosmos.
 It is said that Plotinus bridged the gap between Eastern religions and Western thought. His work is thoroughly grounded in Greek philosophy, and his debt to Plato is without question. But Plotinus' great contribution to philosophy was inspired through his own interior experiences. This 'inner illumination' became the means of explicating the architecture of the universe, which is but a reflection or image of the divine within every human soul.
The system in which all reality participates is a graded system of three hierarchies or hypostases, and is often called the Divine Triad. Each member of the triad is characterized by two movements or acts, and each movement is thought of as an emanation, or radiation, or outpouring accompanied by reversion-to-source or return upon principle. All phases and forms of existence flow from this trinity, and all strive to return and remain there.  Each hypostasis is variously named, the ultimate principle being simply called the ONE, in some instances the Supreme, the Absolute, the Good, or the Father. The intermediate principle or hypostasis is called Mind; Intellectual-Principle, Intelligible Realm and in Greek--Nous, and the last or lowest principle being called the World Soul or the All Soul. The universe proceeds from an eternal first principle, the ONE, from which arises Mind or Intellect, and in turn produces the World Soul, the creative
principle of the material world.
The ONE has a strange characteristic about it. It cannot be known. Its nature transcends all the knowable, hence we cannot properly attach any name to it. We are only able to speak of what it is not, not what it is: "We do not grasp it by knowledge," Plotinus says, "but that does not mean that we are utterly void of it; we hold it not so as to state it, but so as to be able to speak about it. . . unable to state it we may still possess it."  What Plotinus seems to be saying is that the ONE is too near to us to become an object for our thought, and when we try to make it an object, we fall away from it. As he says, "We hover about it trying to interpret our own feelings about the ONE, sometimes drawing near and sometimes falling away in our own complexities about it."
The ONE is a cause only in that its perfection implies an act, and the most perfect form of expressive act is thought or Intellection. In other words, perfection is not something that comes out of nothing; as a process it must be active or it could not become what it is. Perfection, as an active process, is realized as a product of thought.
The ONE does not remain self-enclosed, but radiates its abundance. As the ONE over-flows, it turns back upon itself, and in the act of contemplating, knows itself. The result of this act is Mind or Intellect--the second hypostasis of the Divine Triad. This is really the first thing which, if only in some vague sense, may be affirmed. As the act, offspring, and image of the Supreme, it is a sort of mediation to us of the unknowable ONE. Mind, or the Intellectual Universe, as the totality of thoughts, are the eternal originals, Archetypes, Intellectual Forms of all that exists in the lower spheres. This is the realm of Plato's world of forms, or his intelligible world of which the sensible world is but an image. The Intellectual World or Mind does not remain unproductive. Intellect "engenders a power apt to the realization of its thought," apt, that is, to "creation." This engendered power is the third hypostasis of the Divine Triad. The third hypostasis is, then, the World Soul. As mentioned, each member of the triad has two acts--that of emanation from, and reversion to, source. As Mind has two acts--that of upward contemplation of the ONE and that of generation toward the lower--the World Soul also has two acts. It at once contemplates the Intelligible realm, and generates in its own bounty the lower forms of beings, that is, the things of the physical world. Plotinus considers this the creative principle of our world.
Plotinus stresses the transcendence of the ONE to an extreme degree, but he is careful to exclude all ideas of a quasi-spatial sort about this transcendence. The ONE is not a God outside the world or remote from us, but present within us, or rather we are in Him, for Plotinus prefers to speak of the lower as in the higher rather than the other way around; body is in Soul, Soul in Mind, and Mind in the ONE. This hierarchical order does not imply the remoteness of the ONE, because the levels are not spatially separate from each other, but present together everywhere.
Intellect proceeds from the ONE without affecting its source. The ONE loses nothing; there is simply a giving-out that leaves the ONE undiminished and
unchanged. Emanation is conceived by Plotinus as an out-going from the source as light from a light-source, or heat from fire, or the aroma from perfume. It is distinct from its source yet leaves its source undiminished. Plotinus also considers this giving-out or emanation from the ONE as an out-going of Goodness. The ONE or the Good is self-overflowing; good means generosity, which is the reason there is emanation in the first place. It is the source of all goodness in the world. Plotinus states that "this principle is not to be identified with the good of which it is the source; it is good in the unique mode of being the Good above all that is good."
The second hypostasis--Mind or Intellect--corresponds in Plotinus to Plato's world of Forms or Ideas. Intellect is both thought [unity] and objects of thought [multiplicity]. Intellect is a whole or a unity of all thought, while each thought as an object of thought is unique and individual. Thus we have a unity in difference, and difference in unity. But Plotinus goes beyond this in transforming Plato's Forms from a logical, mathematical structure of static universal ideas into an organic living community of interpenetrating beings. Forms and intelligences are at once all "awake and alive," in which every part thinks and in a real sense is the whole. Therefore the relationship of whole and part in this spiritual world is quite different from that in the material world, and involves no
exclusion or separation. The Intellectual Realm is infinite in power, but finite because it is composed of an existing number of ideas that are definite, limited realities. From our own experience, Intellect is the level of intuitive thought, a thought that grasps its object immediately and is always perfectly united with it, and does not have to seek it outside itself by discursive reasoning.
 The material universe is the lowest stage in the cosmic order, which lies within the sphere of the third hypostasis--the World Soul. Since nothing stands between Intellect or Mind and the production of a world, there must be a formed world corresponding to the formative power. Time belongs to the World Soul as eternity to Mind. As Plotinus says: "Time is the moving image of eternity." The World Soul is produced by Mind and Mind by the Primal One. Thus the World Soul is in contact at once with eternal being, and with the temporal things that it generates by the power it receives from its cause.  The World Soul has for its work not only to think, but to order and rule the things after it. These come to be because production does not stop at Intelligibles, but must go on to the limit of all possible existence. Infinite variety is demanded that the whole in all its parts might be perfect.
Plotinus identifies contemplation with production. The World Soul's production is an overflow from its quiet contemplation. But its contemplation is weak, and what it produces is a poor image or reflection of the lowest vestige of its thought.
Plotinus insists, in opposition to Aristotle, that there can be no real union between form and matter. Even the lowest vestige of Soul in body does not quite unite with matter to form the concrete material thing, but is externally superimposed upon it. The contact of matter with the Intelligible World is in "participation" by which matter receives what it can receive. Matter is the receptacle in the visible world which images the Intelligible World. Matter is completely formless and indeterminate, and communicates its indeterminateness to the form that is impressed upon it.
Plotinus regards matter as the principle of evil. Although the world has evil in it, he is eager to maintain that it is as good as it can be, and even that it is in essence good, and only accidentally evil. Matter by its absolute want of all form is at the opposite extreme to things Intelligible, and is in its own nature ugly and evil. The degree of our participation in the material world determines the extent of the soul's possible involvement in evil activities.