A short criticism of Gifts of the Muse that really irritated me. The logic, as I understood from the summary Ian put forward, is thus:
1) Data on extrinsic (instrumental) benefits of the arts are not well documented.
2) Data on intrinsic benefits of the arts are difficult to define, and thus also not well documented.
3) Thus, we need to focus more on the intrinsic benefits of the arts.
It's not so much as there's a flaw of logic there as I'm not sure where the logic is coming from. Given that neither has a particularly well-proven or well-documented correlation (although both have strong indicators), why would that be an argument for choosing one over the other?
The sagest thing they say is "not much is gained by separating the discussion of instrumental benefits from that of intrinsic benefits--the two are intimately linked."
I'll see when the book arrives and I can read it myself why it had such an impact on behalf of intrinsic benefits. I find myself unconvinced one way or the other.