Parmenides

The young Socrates meets the great philosopher Parmenides of Elea, then about sixty-five, and his pupil Zeno in Athens. Socrates presents his theory of Forms, the perfect, unchanging ideas behind things, and Parmenides raises powerful objections to it, among them the argument later known as the 'third man'. Then the old philosopher gives a demonstration of reasoning: a long series of arguments about whether 'the One' exists or not, which reaches contradictory conclusions.

Written in Plato's later years, the Parmenides is the most puzzling of his dialogues, a criticism of his own theory that the later Neoplatonists read as a mystical theology. Benjamin Jowett's translation keeps the long chains of argument as clear as English allows. Read Sophist and the Republic.

Plato (c. 428–348 BC) was born into an aristocratic family in Athens and became the devoted student of Socrates. After his teacher's trial and execution in 399 BC, he travelled, returned to Athens and founded the Academy, a school that lasted for centuries and counted Aristotle among its students.

Almost all his writings are dialogues in which Socrates questions his fellow citizens about justice, love, knowledge and the soul, from the Apology to the Symposium and the Republic. Known to Arab philosophers as Aflatun, he was read closely by al-Farabi and Ibn Rushd, and Western philosophy has been called a series of footnotes to him.