He is accordingly called by the poet Theaetetus, in an epitaph which he composed upon him, the friend of the Muses; and we are told, that his chief favourites among the poets were Homer and Euripides.
The argument can be seen as a response to the suggestion in Plato's Theaetetus that knowledge is justified true belief.
but Plato in his recent dialogues, as Theaetetus or Sophist had a different method to Philosophical discussions, namely Dialectic.
When these solids were all discovered and by whom is not known, but Theaetetus, (an Athenian), was the first to give a mathematical description of all five (Van der Waerden, 1954), (Euclid, book XIII).
It traces the early history of irrational numbers from their first discovery (in Thebes between 430 and 410 BC, Knorr speculates), through the work of Theodorus of Cyrene, who showed the irrationality of the square roots of the integers up to 17, and Theodorus' student Theaetetus, who showed that all non-square integers have irrational square roots.