Sophist

A late dialogue led not by Socrates but by a visitor from Elea, who sets out to define the sophist with the young Theaetetus. Using the method of division, splitting a kind into ever narrower parts, he first tries it on the angler and then catches the sophist under several descriptions, from paid hunter of wealthy young men to trader in learning. The sophist finally appears as a maker of images who passes off appearances as truth. That raises a hard problem: to speak of falsehood seems to require saying what is not, which Parmenides forbade. The visitor reviews the dispute between materialists and friends of the forms, proposes that being is the power to act or be acted on, and examines five great kinds: being, change, rest, sameness and difference. Not-being turns out to be difference, and a false statement, such as 'Theaetetus flies', says of something what is different from what is.

It explains how false statements are possible and analyses the simple sentence, making it a founding text of the philosophy of language as well as of ontology.