Hmmm... I'm wondering how to interpret the astounding silence of DB readers as regards the 'Sachs problem'. (Yes, I well understand it's a busy time of the academic year.)
I'm planning to continue this thread by looking at recent solutions proposed by Eric Brown and Terry Penner. (And, not to worry, I'm initiating other threads besides.) But I wonder if you have thoughts on my suggestion of how to understand the problem.
We saw that Sachs (following Grote) says that Plato has changed the subject. Plato wants to show, at the beginning of Rep. II, that it is preferable not to steal, break an oath, murder, betray, etc., even apart from any good results of acting in this way, and even if it brings bad results. But what he actually argues for, in Rep. IV, is that it's in this way preferable to have a harmonious soul. That leaves a gap. What is the argument that takes us from 'harmonious soul' to 'consistently acts justly' and back?
What I proposed is the following. We see in Rep. IV that Plato, at least, seems most concerned with establishing this claim:
The word 'just' as applied to an individual with a harmonious soul is used in exactly the same way as when the word is applied to an ideal, well-ordered city.I urged that the Sachs/Grote problem then becomes: What line of argument takes us from the above claim (the 'Univocity Thesis') to the claims that: someone with a harmonious soul refrains from ordinary acts of injustice; and someone who refrains (consistently and with stability) from ordinary acts of injustice has a harmonious soul. (And then it seemed possible to give a line of thought which achieved this, since we could reasonably hold that ordinary acts of injustice would be forbidden by law in an ideal city. But see the earlier post.)
You may not agree with exactly how I supposed that Plato wished to bridge this gap. But do you agree that this is a useful way to conceive of the argumentative task?