Timaeus

The Timaeus is a dialogue by Plato, written around 360 BC, in the last phase of his literary output. It has been regarded as one of the most influential works in later philosophy and science, and it is among the most studied texts of the Platonic corpus. Its authenticity is firmly established, although its interpretation remains a subject of debate.

The dating of the work is one of the most discussed questions. In the nineteenth century, scholars proposed a developmental reading of Plato's thought that placed the Timaeus before the Parmenides, since its defence of the theory of Forms seemed incompatible with a later critique. Stylometric studies, based on the frequency of hiatus, linked it to late stages of his writing. Later scholars such as Cherniss argued that its doctrine was fully compatible with Plato's maturity. Today it is usually regarded as a dialogue of old age, together with the Critias, the Philebus and the Laws.

The dialogue takes place the day after a conversation about the ideal state, which is identified with the Republic. The participants are Socrates, Timaeus of Locri, Critias and Hermocrates. Timaeus, a figure associated with Pythagorean tradition, delivers the long speech that gives the work its title. Critias then recounts the story of Atlantis and of an earlier Athens, which leads into a war between the two cities. Plato seems to have planned a third part, featuring Hermocrates, which was never completed.

The philosophical core of the Timaeus distinguishes between the sensible world, which changes and perishes and is the object of opinion, and the eternal, unchanging world, accessible only to reason. For this reason, an account of the physical world can be no more than probable. The universe is the work of a divine craftsman, the Demiurge, who, being good, orders a chaotic matter by taking the eternal Forms as his model. The world thus becomes a living being endowed with soul and intelligence, spherical and rotating, whose soul is composed through mathematical proportions of sameness, difference and being. The speech then describes the creation of the astral gods, of humankind, with its immortal soul and mortal body, and of the animals.

The work exercised exceptional influence in Late Antiquity and the Middle Ages. Calcidius's partial Latin translation made it for centuries almost the only Platonic source available in the West, and its ideas about the Demiurge, providence and the harmony of the cosmos shaped Neoplatonism, Christian thought, and Renaissance astronomy and mathematics. Its vision of a universe ordered by geometric proportions remained a constant point of interest, from the theory of the Platonic solids to modern reflections on the mathematical nature of the world.