  The usual Unitarian answer is that this silence is studied. In the Theaetetus, Unitarians suggest, Plato is showing what knowledge is not. His argument is designed to show that certain sorts of alternatives to Plato’s own account of knowledge must fail. Plato demonstrates this failure by the ‘maieutic’ method of developing those accounts until they fail. Thus the Theaetetus shows the impossibility of a successful account of knowledge that does not invoke the Forms. 