Plotinus (205-270 CE) was the founder of Neoplatonism. He was born in Lycopolis, Egypt, and became interested in philosophy when he was 28. He studied philosophy in Alexandria under Ammonius Saccus (175-250 CE), before traveling to Persia in 243, and settling in Rome in 244, at the age of 40. In Rome, he taught philosophy, and became a friend of the Emperor Gallienus. Plotinus tried to persuade Gallienus to build a city called Platonopolis which was to be governed according to the model of Plato’s Republic, but the plan eventually had to be abandoned. Plotinus lived in Rome from 244 to 268, and produced his philosophical writings from 253 to 270. He died in 270, in Campania, Italy.
After his death, Plotinus’s writings were edited by his student Porphyry, who arranged them into six groups, each consisting of nine treatises, making a total of fifty-four treatises (the title Enneads refers to these "groups of nine," and is derived from the Greek word for nine, ennea). The Enneads are an extended investigation of the nature of the Soul, and of the relation of the Soul to divine Intellect and to divine Unity.
The First Ennead discusses the nature of virtue, happiness, and beauty. The First Ennead also explains how Platonic dialectic may be used as a method of understanding reality. The Second Ennead investigates the nature of matter, and describes the relation between potentiality and actuality. The Third Ennead discusses the nature of Providence and Free Will, and describes the nature of Time and Eternity.The Fourth Ennead discusses the immortality of the Soul, and examines the relation of the Soul to the body. The Fifth Ennead discusses the three hypostases (or underlying principles) of reality: the One, the Intellectual Principle, and the Soul. The Sixth Ennead discusses the kinds of Being which may be established by the Intellectual Principle, and describes the multiplicity of Ideas which may be found in the Intellect. The Sixth Ennead concludes with a discussion of the Good (the moral nature of the One).
According to Plotinus, the Soul attains virtue by devoting itself to the Intellectual Principle. Wisdom and understanding are attained by contemplation of the Intellectual Principle. The Intellectual Principle is a higher principle of reality, through which the Soul can be released from the body.
Plotinus discusses two classes of virtue: the 'civic' virtues and the 'purifying' virtues. The 'civic' virtues include: prudence, justice, fortitude, rectitude, and moral integrity in applying all the other virtues appropriately. The 'purifiying' virtues are a higher class of virtues, including knowledge, wisdom, and understanding, which 'purify' the Soul, and which enable the Soul to transcend itself.
Plotinus explains that Platonic dialectic is a method of discovering truth which enables the Soul to ascend to the realm of Intellect. Dialectic is the perfection of wisdom and of Intellect. Dialectic reveals the contradiction between the Not-Good and the Good, between the temporary and the eternal, between empirical knowledge and absolute knowledge. Plotinus also says that the Proficient Soul is a Master of Dialectic (I.3 Ch. 6). The Proficient Soul is able to ascend to a realm of Intellect which can resolve contradiction. Thus, the Proficient Soul has the necessary wisdom to seek the Good, and to find the way to happiness.
The Good is that on which everything else depends (I.8 Ch. 2). The Good is the source of reality for all Being. According to Plotinus, Evil is a mode of Non-Being. Absolute Evil is a mode of absolute Non-Being. Non-Being is opposed by Real-Being. But Plotinus is unable to resolve the problem of whether or not Evil actually exists, because his assertion that Evil is an absence of Good contradicts his assertion that Evil cannot exist unless there is Good.
The Intellectual Principle is an act of the Good, which gives Reason and Form to the universe, and which brings the universe into Being. The Intellectual Principle establishes Being as an act of Intellect (V.1 Ch. 4). The Intellectual Principle (Divine Mind) also gives order to the Cosmos. The Intellectual Principle gives a Reason-Principle to all beings or things which are Authentically Existent. The Reason-Principle (or Logos) of the Cosmos emanates from Divine Mind, but is not itself the Intellectual Principle. The Reason-Principle can be seen in the conflict and contradiction of elements in the universe, and thus gives Form to the universe as a totality, but does not bring the universe into an undivided unity.
The Reason-Principle is a Principle of the Soul. Everything that exists has its own Reason-Principle. Every Soul has a Reason-Principle. The Reason-Principles of all Souls are expressed by the Universal Soul. The Universal Soul is a compound unity of all Souls, and is the source of every individual Soul. The Universal Soul is not an aggregation of individual Souls, but is an undivided unity. Plotinus also describes the Universal Soul (or All-Soul) as an Ideal Principle of Real-Being (III.6 Ch. 17).
The One is the source of the Intellectual Principle, and is the source of the Intelligible World. The Intellectual Principle is the source of the Soul. The One illuminates the Intellectual Principle, and the Intellectual Principle illuminates the Soul.
The One is the source of Life, of the Intellect, and of the Cosmos (III.8 Ch. 9). The One is the source of all reality, and is that on which all Authentic Existents depend for their Being. The One is a supreme principle which transcends Being, and which transcends the Intellect. According to Plotinus, the One is not an Intellect; it is the Good. The One is the source of the universal Intellect (Divine Mind), but is not itself a Mind, and cannot be known by the Intellect. The One transcends knowing or being known.
Plotinus says that Ideas are the content of the Intellectual Principle. Ideas are many, and not One. Anything which can be known by the Intellect is not the One. The One is an infinite and absolute reality which transcends the Intellectual Principle. The Intellectual Principle is a Principle of Mind which establishes Real-Being. Real-Being is illuminated by the Intellectual Principle. Plotinus explains that the Intellectual Principle is not only in all things, but is all things (III. 3  Ch. 3). Thus, the Cosmos (the World of Real-Being) is the Being of the Intellectual Principle, and is a compound unity. The totality of Being is a compound of many substances or constituents, and is therefore not the One. The One is not a compound substance, but is an absolute unity.
According to Plotinus, the perfection of the universe is a process by which lesser Being seeks to become more like higher Being. The Soul seeks to become like the Intellectual Principle, and the Intellectual Principle seeks to become like the One. Each Soul is an Intellectual Cosmos which seeks a guiding spirit to lead it to a higher level of Being. The Sage is a Soul whose actions are determined by a higher level of Being. The Sage is a Soul which is guided not merely by its own will, or by the instincts of the body, but by Divine Mind.
Plotinus claims that the Soul may be embodied or unembodied. The Soul may or may not inhabit the body, and can ascend from, or descend into, the body. The Soul can live without the body, but the body cannot live without the Soul. The body is illuminated by the Soul. The unembodied Soul is a higher phase of the Soul, while the embodied Soul is a lower phase of the Soul.
Plotinus says that the unembodied Soul has no sensory perception. Perception occurs by means of the body (IV.4 Ch. 24). Thus, the memory of sensory perceptions depends on the Soul having lived in the body.The Soul itself cannot be directly perceived, because it does not belong to the sensory world. But the Soul can know itself by becoming like the Intellectual Principle. Self-knowledge is achieved when the knowing agent (the known self) is the same as the act of knowing (V.3 Ch. 5). In the Intellectual Principle, the thinker is the same as the thought, and the knower is the same as the known, because the Intellectual Principle transcends any distinction between Being and Knowing (III.8 Ch. 8). Plotinus explains that Truth is this sameness or identity in the relation between the knower and the known.
Plotinus also says that the Soul cannot be separated from the body by an act of violence or by suicide, because acts of violence are not guided by the Reason-Principle of the Soul. Acts of violence or suicide leave the Soul attached to the body (I.9). The Soul can only be released from the body by seeking a higher level of reality in the Intellectual Principle.
Time is the Life of the Soul, in that the Life of the Soul is expressed as a continuous sequence of acts. Time is in every individual Soul of the Universal Soul, and is thus a constituent of the All-Soul. Plotinus says that Time is found in the activity of the Soul, but that the Soul itself is eternal. Being in Time is to be distinguished from Being in Eternity (III.7 Ch. 7). Time is a changing reality, while eternity is an unchanging reality.Time is a property of the Soul, but Eternity is a property of the Intellectual Principle. Eternity is the Life of the Authentic Existent, which may be a guiding principle for the Life of the Soul.
Plotinus enumerates three hypostases, or underlying principles, of reality: the One (the First Hypostasis), the Intellectual Principle (the Second Hypostasis), and the Soul (the Third Hypostasis). The One is the highest principle of reality, and is the Good. The One transcends Being and Knowing. The Intellectual Principle is the next highest principle of reality, and determines the realm of Being. The Intellectual Principle is an act (or image, or emanation) of the One. The Intellectual Principle illuminates the Intellectual Soul. The Soul is an act (or image, or emanation) of the Intellectual Principle. The Intellectual Soul is the highest phase of the Soul, followed by the Reasoning Soul, followed by the Unreasoning Soul.
The Intellectual Principle is the highest principle of Being. The Reason-Principle is the next highest, followed by the Nature-Principle. Each of these Principles of Being is an Ideal-Form, and is not a compound of Form and Matter (III. 8 ). Nature may be a Reason-Principle which is found in the World of Real-Being. Nature may thus be an act of contemplation by the Soul. However, Nature may also be without a Reason-Principle. Nature may be an object of contemplation by the Soul.
Matter is essentially indefinite, and is undefined by the Reason-Principle. Matter is soulless, lifeless, and bodiless. Matter is indeterminate, Reason is determinate. A Reason-Principle may coexist with (or may be opposed to) Matter, but Matter is essentially empty of the Reason-Principle. Matter is initially formless, but may be shaped by Ideal-Forms. Matter is necessary to the body, and may be shaped into the Form of the body.
Plotinus attacks Gnosticism for its doctrine that all Matter is evil, and for its doctrine that Matter is created by a Demiurge who is evil. According to Plotinus, the One, or the Good, is the source of all reality. Plotinus also attacks Gnosticism for its claim to be a mystical knowledge of the only path to salvation (or to the release of the spirit from the body). Plotinus also attacks Gnosticism for its disbelief in Divine Providence. According to Plotinus, Divine Providence is in accordance with Divine Intelligence (Divine Mind). The Intellectual Principle gives a Reason-Principle to the universe, which develops according to Necessity. Divine Providence determines the Reason-Principle (or Logos) of the Cosmos to be a principle of Good, and not of Evil.
Plotinus says that Evil is caused not by Providence, but by Necessity. Evil can only exist as a lack of Good. Human beings are free to choose their own actions, and are not forced to be evil. Plotinus claims that Necessity is a universal relationship, and that it is not a force which predetermines the actions of individuals or which compels them to act in a particular manner (III.2 Ch. 10). The freedom of the Soul is affirmed by the Soul’s illumination by the Intellectual Principle so that the Soul is able to act according to the Good.
Plotinus also discusses the views of other philosophers, concerning the nature of the three hypostases of reality. Plotinus agrees with Plato that the Good transcends Being, and that the Good transcends the world of Forms and Ideas. Plotinus agrees with Parmenides that the Intellectual Principle reveals that Knowing is the same as Being. Plotinus agrees with Heraclitus that bodily forms are subject to endless change, and that the One is eternal. Plotinus agrees with Aristotle that the First Cause is transcendent, and that it is the source of the Intellect. However, Plotinus disagrees with Aristotle that the First Cause can be the object of its own Intellect.
Thus, Plotinus develops a philosophical system which combines the influences of many schools of classical Greek philosophy, including Platonism, Aristotelianism, and Neo-Pythagoreanism. Plotinus’s Enneads present the doctrine that there is a First Principle of reality for all other reality, and that this First Principle of reality is a oneness or unity which transcends all Being.
Hamlyn, D.W. “Greek Philosophy After Aristotle,” in A Critical History of Western Philosophy. Edited by D.J. O’Connor. New York: The Free Press, 1964.
Merlan, Philip. “Plotinus,” in The Encyclopedia of Philosophy. Edited by Paul Edwards. New York: Crowell, Collier, and MacMillan, 1967.
Plotinus. The Enneads. Translated by Stephen MacKenna. London: Penguin Books, 1991.