Plotinus, the most original and important philosopher of the Neoplatonic school, was born at Lycopolis in Egypt in 205 A.D., and studied philosophy under Ammonius Saccas. In 242 he joined Gordianus' expedition to Persia, in order to study the philosophy of India and Persia; but the emperor being murdered in Mesopotamia, he returned hurriedly to Antioch, whence, in 244, he went to Rome. His lectures here were attended not only by crowds of eager youths, but men and women of the highest circles flocked to hear him. Not only Neopythagorean and Neoplatonic wisdom, but asceticism and the charm of a purely contemplative life were the themes on which he, in ever new variations, and with an extraordinary depth and brilliancy, held forth; and such was the impression his earnestness made upon his hearers that some of them really gave up their fortune to the poor, set their slaves free, and devoted themselves to a life of study and ascetic piety. It is hardly surprising to find that his contemporaries coupled with his rare virtues the gift of working miracles. Sixty years old, he thought of realising Plato's 'Republic,' by founding an aristocratical and communistic commonwealth; and the Emperor Gallienus was ready to grant a site in Campania for his 'Platonopolis;' but he died near Minturnæ in 270. Although he began to write very late in life, he yet left fifty-four books of very different size and contents to the editorial care of his pupil Porphyry, who arranged them in six principal divisions, each subdivided again into nine books or Enneads.
Plotinus' system was based chiefly on Plato's, combined with Neopythagoreanism and the oriental theory of Emanation—i.e. the constant transmission of powers from the Absolute to the Creation, through several agencies, the first of which is 'Pure Intelligence,' whence flows the 'Soul of the World,' whence, again, the souls of 'men' and 'animals,' and finally 'matter' itself. Men thus belong to two worlds, that of the senses and that of Pure Intelligence. It depends upon ourselves, however, to which of the two worlds we direct our thoughts most and belong to finally. The ordinary virtues, as justice, moderation, valour, and the like, are only the beginning and very first preparation for our elevation into the spiritual realm; purification is a further step, to which we attain partly through mathematics and dialectic; and the abandonment of all earthly interests for those of intellectual meditation is the nearest approach to the goal. The higher our soul rises in this sphere of intellect, the deeper it sinks into the ocean of the good and the pure, until at last its union with God is complete, and it is no longer thought but vision and the ecstasy which pervades it. These are a few snatches of Plotinus' philosophical rhapsodies, to which may be added his mysterious belief in a kind of metempsychosis, by which souls not sufficiently purified during life return after death, and inhabit, according to their bent, men, animals, and even plants. He further held somewhat fantastic views as to gods and demons, and professed faith in astrology and magic. His was the last attempt by the ancient world to solve the great problems not by ratiocination, but through introspective mysticism; and his mode of thought had very unmistakable influence on early Christian philosophy, modern theosophy, and various German idealistic systems.
See NEOPLATONISM and works there cited, and works on Plotinus by Kirchner (1854), Brenning (1864), and Kleist (1884).