We’re trying to make sense of them. What do we have to do to do that? Here’s a plausible principle: To make sense of an author, we have to interpret the author as making sense.
What does that involve? Here’s another plausible principle: To interpret an author as making sense, we have to understand the author as believing what it’s reasonable to believe, unless we can explain how they might reasonably have come to believe something unreasonable.
This is a version of the well-known Principle of Charity. If we are to understand an author as believing what it’s reasonable to believe, we have to understand them as believing what we think it’s reasonable to believe. So it looks as if interpreting an author like Plato will inevitably find them believing what we believe – except insofar as we can explain how they might reasonably have come to believe something else. If you bear this in mind, you won’t be surprised that the interpreters of a given age find Plato holding the dominant philosophical views of that age, and that they find in Plato’s oeuvre a process of development which mirrors what they take to be the philosophical advances of their own age.
Most interpreters of Plato hold the views of Ordinary Jo (see Part 1, Step 2). That is, they think:
And they think this last thing because they think: The same person can’t possibly have competing desires or contradictory beliefs at the same time
There is an argument in the Protagoras (roughly 351b-358c) which seems to show that akrasia is impossible. And there is an argument in the Republic (roughly 435e-441c) which seems to accept that akrasia is possible.
Most interpreters see here a development in Plato’s thought which brings Plato into line with what they think is reasonable. So in the Protagoras, they think he rejects the views of Ordinary Jo. But they think this is just early Plato, when they think he was still mouthing the views of the eccentric and paradoxical Socrates. By the time of the Republic they think he’s matured, and has come to see the truth of the views they hold themselves – that is, the views of Ordinary Jo.