  As Plato stresses throughout the dialogue, it is Theaetetus who is caught in this problem about false belief. It is not Socrates, nor Plato. There is clear evidence at Philebus 38c ff. that false belief (at least of some sorts) was no problem at all to Plato himself (at least at some points in his career). Plato’s question is not “How on earth can there be false judgement?” Rather it is “What sort of background assumptions about knowledge must Theaetetus be making, given that he is puzzled by the question how there can be false judgement?”