The collective designation for the philosophical and religious teaching of a heterogeneous school of speculative thinkers who sought to develop and synthesize the metaphysical ideas of the Greek philosopher Plato. Such synthesis took place in Alexandria and included Hellenistic Judaism, as exemplified by the Jewish-Hellenistic philosopher Philo Judaeus of Alexandria, as well as other views.
The Neoplatonic doctrine originally was essentially Greek; however through the centuries other metaphysical systems were absorbed into it until it became a heterogeneous doctrine. Principally Neoplatonism is a type of idealistic monism. It states the ultimate reality of the universe is held by an infinite, incogitable, perfect One. From this perfect one emanates nous (pure intelligence), from which is derived the world soul, and lesser souls are derived from it. The world soul is conceived as an image of the nous, just as the nous is seen as an image of the perfect One; both the nous and the world soul, despite their differentiation, are thus consubstantial with the perfect One. The world soul, however, because it is intermediate between the nous and the material world, has the option of either preserving its integrity and imagined perfection or of becoming altogether sensual and corrupt. Each of the lesser souls engendered from the world soul has the same choice.
When, through ignorance of its essential nature and identity, the human soul experiences a false sense of separateness and independence, it becomes arrogantly self-assertive and falls into sensual and deprived habits. However, the Neoplatonic doctrine maintains that salvation is still obtainable. Salvation is possible by the very freedom of choice which allowed the soul to choose its destructive course. Now, the soul must reverse itself by tracing in the opposite direction the successive steps of its degeneration, until it is again united with the fountainhead of its being. This actual reunion is accomplished through a mystical experience in which the soul knows a prevailing ecstasy.
Doctrinally, Neoplatonism is described as a categorical opposition between the spiritual and the carnal—the spirit and the flesh—which is an elaboration of Plato’s dualism of Idea and Matter, which is conducted in metaphysical hypothesis by mediating agencies; the nous and the world soul , which transmit divine power from the perfect One to many; by an aversion to the world of sense; and by the necessity of liberation from a sensual life through a staunch ascetic discipline.
Neoplatonism began in Alexandria, Egypt during the third century AD. Its founder was Ammonius, an Alexandrian philosopher, whose surname was Saccas, referring to his former occupation of "the sack bearer," or a porter. The foremost exponent of the teachings was the Roman philosopher Plotinus (c. a. 205-270), who was born in Egypt, studied with Ammonius in Alexandria and took the Neoplatonic doctrine to Rome. After settling in Rome his major works were the Enneads, that contains a comprehensive exposition of Neoplatonic metaphysics.
Other important Neoplatonic thinkers were the Syrian-Greek scholar and philosopher Porphyry (c. a. 232-304), the Syrian-Greek philosopher Iamblichus (d. 333), and the Greek philosopher and mathematician Proclus.
Since Neoplatonism contained elements of asceticism and unworldliness it was strongly favored by the early Fathers of the Christian Church. Saint Augustine, in his Confessions, acknowledged the contribution of Neoplatonism to Christianity and stated it greatly influenced his own religious thinking. But, the doctrine had a turbulent relationship with the Roman Catholic Church. It was banned by Emperor Justinian I in 529. The dogmatists condemned it for its unorthodox tenets. However, by the 15th century Neoplatonism was generally accepted.
The revival of Neoplatonism begun with the German Roman Catholic speculative philosopher Nicholas of Cusa and other mystics who sought to overcome the doubt arising from the limitations of human knowledge by espousing the theory of man’s direct intuition of God. Such a theory was closely aligned with the Neoplatonic doctrine that the soul when in a state of ecstasy has the power to transcend all finite limitations. A further development of the Neoplatonism revival was contributed by the Humanists during the Italian Renaissance. Because of their reaction against the previously dominant rationalistic Aristotelian philosophy, they turned to the idealistic metaphysics of Plato, thus to Neoplatonism. This further development was greatly aided by the Italian scholar Marsilio Fficino (1433-1499), under the patronage of the wealthy Cosimo di Medici, translated and annotated the works of Plotinus, Porphyry and Iamblichus.
In England, the 17th century Cambridge Platonists showed marked affinity toward Neoplatonism. So did several intellectuals and writers of the 19th and 20th centuries, namely English poets William Wordsworth, John Keats and Perch Bysshe Shelley.