A talk by Christine M. Korsgaard, “Interacting with Animals: A Kantian Account” (as summarized by a student):
Peter
Singer . . . has argued that . . . there is no disutility cause by painlessly killing a non-human animal. Nothing is lost. The utility that would have been
created by the animal’s future pleasure can be added by breeding another animal to take its place. For Singer, this is not the case with humans because due to our ability, and tendency, to plan, etc., more is lost when one of our lives ends. When we die something (morally relevant) is taken from the world that cannot be replaced.
But [Singer's utilitarianism] gives no
explanation as to why it is not morally acceptable to kill a person
painlessly. Singer might reply that because a person has expectations
and plans, awareness of the imminence of death causes more disutility
for humans than for other animals. This cannot save his theory,
however, because he can still not explain why it is wrong to kill a
person quickly, painlessly and by surprise.
. . .
After rejecting Singer’s argument, Korsgaard put forth her own view.
Since her approach is Kantian, or deontological, she is not focused on
maximizing the good in the world, but on interactions between
individuals. This is important because it allows her to get away from
comparisons between the values of human goods and non-human animal
goods.
. . .
One is not only obligated
to those with whom she has shared laws, rational beings, but also to
the source of interests that the law she is under was made to protect.
. . . . The weak version [of Korsgaard's thesis] is that some of the interests
of our animal nature, that are given value by our rational nature, are
shared by other animals and we must protect these.