Theaetetus is one of the finest of Plato’s middle-period dialogues. It may well have been written as a tribute to the historical Theaetetus shortly after Theaetetus’s death from wounds suffered in battle. This conjecture rests on the fact that the speakers who introduce the main dialogue, but play no other role, refer to the return of the dying Theaetetus. This event serves as an occasion for them to read together a report of a conversation that took place a number of years previously between Socrates and Theaetetus. At the time, Socrates was awaiting his trial, so we are to assume that Socrates was seventy years old and that Theaetetus was a youth of about sixteen.
The dialogue proper opens with a conversation between Theodorus (Theaetetus’s teacher) and Socrates in which Theodorus praises Theaetetus highly. Socrates is impressed, and he calls the boy over to converse with him to see if Theodorus’s estimate is a fair one. Socrates tells Theaetetus of his occupation as an intellectual midwife and requests Theaetetus to let him use his art to see if Theaetetus will give birth to anything. The boy responds eagerly but respectfully, and the philosophical portion of the dialogue gets under way.