Let's consider Lear's interesting arguments one-by-one. Do they stand up?
In this post I look at the first argument, that the basis of Plato's division is different from Aristotle's, because it is a division of 'ways that goods supply us with happiness'.
The argument is as follows:
Notice that Socrates says that the second group is the finest, because it provides its possessor with happiness by two routes: The good thing will itself make him happy, and it will lead him to other sources of happiness (Rep. 358a). This suggests that Glaucon's groups are distinguished by the different ways they supply us with happiness.
But what Socrates actually says is:
One small point to put aside. Is it significant that Socrates does not refer here to a 'happy' man (eudaimon) but rather to a 'thoroughly blessed man' (makarios)? No, Plato uses these terms interchangeably: cf. 354a. Nothing can be made of that.
The more important point is this. Plato seems to be supposing something like the following principle:
Something that is valuable only because it leads to other valuable things is appropriately loved for that reason. Something that is valuable in its own right is appropriately loved for that reason. And something that is valuable on both grounds is appropriately loved for both reasons--on pain of unhappiness (presumably, if the thing is non-trivial).
Glaucon's challenge is for Socrates to show:
It is assumed:
From which it would follow that:
And, if this were shown, then Thrasymachus would be satisfactorily refuted. The task of Republic II-IV then becomes to establish 2.
Note that there is nothing here about a good in the second class itself making someone happy: it's our love of that good, on the correct grounds, which is a requirement of happiness.
Again, there is nothing here about goods' being classified as to whether they lead to happiness or not, or sources of happiness. The goods that (everyone acknowledges) justice typically leads to, are such things as a good reputation and credibility in commercial transactions, not happiness.
In any case, the idea that the classes are 'distinguished by the different ways they supply us with happiness' seems to have no application to Glaucon's first and third classes:
- Members of the first class--including such goods as joy and non-harmful pleasures--supply us with nothing.
- Members of the third class--including such things as physical training and noxious medicines--supply us with mundane goods such as fitness and health, not happiness.
But what about the other arguments for that claim? We'll look at another tomorrow.