hello bryan,
i have read that book and i agree with you that they do a good job of responding to dawkins' thesis (there is also an interesting collection titled "beyond self-interest" that discusses the issue from a higher-level perspective, which includes sen's paper titled "rational fools"). ruth hubbard also has an interesting book called destroying the gene myth (or some such) - i am at a public terminal and do not have time to search for the right title - which again addresses some of these issues.
i am not an economist and i do not understand the finer details of sen's paper but his critique of the use of the notion of "revealed preference" by selfish agent theorists seems to be equally applicable to those who redefine altruism as some sort of selfish selection - if not for one's survival, then for the survival of one's genes - thus getting past some of sober and wilson's arguments such as the example they mention at the beginning of the book (the amazing story of an organism that helps its siblings by sacrificing itself).
recently this whole dawkins/gould/et al debates seem to have gained new blood - ullica [complex last name] recently authored what seems to have become a successful if one-sided book called 'defenders of truth' (with attention to the politics surrounding wilson/lewontin and the rest). then there is a little book i saw at b&n at princeton the other day that was, if i remember right, just titled "dawkins vs. gould". there were a bunch more in that vein. lewontin of course has a whole slew of books on the matter (as i am sure you are all aware) ranging from "not in our genes" to the recent "triple helix". there is a web site that chronicles the whole gould/dawkins debates. apologies if this is all well known info.
i am not a biologist either, so i am probably underestimating the complexity of the argument, but carrol's point, if i understand it right, that the word "altruism" has been adopted and used in a particular technical sense by certain biologists in such a way that it is rendered meaningless. it is then pointless to argue against these scientists on their terms.
regards from seattle!
--ravi