Under the term ‘Middle Platonism’, a modern coinage, we refer to the period of Platonic philosophy from 1st c. BCE to early 3rd c. CE, when Plotinus (204-270) comes into the stage. The latter achieves a synthesis that draws on the earlier, Middle Platonic, interpretations, but also goes beyond them, and thus marks the beginning of a new era, named ‘Neoplatonism’. During the period of Middle Platonism we witness rival and often contrasting interpretations of Plato. Most of them, however, are driven by the belief that in his dialogues Plato develops a system of doctrines, although there are also Platonists who advocate the aporetic character of Plato’s philosophy, such as Plutarch and the anonymous commentator on Theaetetus (1st c. CE).
Characteristic of the Middle Platonic period is a revival of the interest in the metaphysics of Plato, especially that of the Timaeus, which goes along with the view that the most central features of Plato’s philosophy come from Pythagoras, given that the character Timaeus is of southern Italy (Τimaeus 20a), where Pythagorean communities flourished. For the most part Middle Platonist interpreters of the Timaeus advance dualistic models of principles, according to which one principle is good and accounts for order and intelligibility in the world, while the other, which is antagonistic to the first, accounts for disorder, irrationality, and badness. Platonists tend to agree that the latter is the receptacle of the Timaeus, which, following Aristotle, they identify with matter, but they disagree with regard to the former principle. They are divided into those who identify this principle with the demiurge of the Timaeus and the Form of the Good of the Republic and those who dissociate the two and claim that the Form of the Good is a principle higher than the demiurge. Both groups of Platonists, though, tend to believe that the demiurge relates to the Forms in the way a thinker relates to his own thoughts, that is, the demiurge comprises the Forms as thoughts.
Important Middle Platonists are Antiochus of Ascalon (ca. 130-68 BCE), Eudorus (1st c. BCE), Plutarch (45/47-120 CE), Numenius (mid 2nd c. CE), Apuleius (125-180 CE), Alcinous (end 2nd c., early 3rd c. CE).