I noted yesterday, that in writing his work on collective choice Sen had apparently read not only the work of John Rawls (which was inevitable), but responses to Rawls about the humans-only nature of the deliberations Rawls imagines behind the veil of ignorance. We are supposed to imagine ourselves as ignorant of our social class, race, and native intelligence, but presumably cognizant of the fact that, when the veil is lifted, we will turn out to be humans. The responses wondered why the species barrier is that strong. What piques my interest is that Sen refers to these critiques (he does not source them specifically -- admittedly it is a bit of a digression from the main line of his thought) as half in jest and half serious. Hmmmm. Has Peter Singer written in response to Rawls? If he has, (and I'm too lazy to look into it right now) then I can easily imagine Singer making the point Sen emphasizes in dead earnest, utterly without jesting. What Sen sees...