If a being suffers there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that its suffering be counted equally with the like suffering - insofar as rough comparisons can be made - of any other being. So the limit of sentience is the only defensible boundary of concern for the interests of others. To mark this boundary by some other characteristic like intelligence or rationality would be to mark it in an arbitrary manner. Why not choose some other characteristic, like skin color?
Peter SingerEffective altruism is the form of altruism in which we bring our rational capacities to bear in order to do the most good that we can.
Peter SingerSurely there will be some nonhuman animals whose lives, by any standards, are more valuable than the lives of some humans.
Peter SingerWhen you look at food as an ethical issue in the Christian tradition, you don't find very much about it. You don't find, as you do in the Jewish or Islamic or Hindu traditions, a lot of restrictions saying you can eat this but you can't eat that. But what you do find is the idea that gluttony is a sin and that it's something that we ought to be ashamed of.
Peter SingerI'd much rather be part of a society which greatly honors and respects people who are altruists and who are effective in their altruism, than one that either admires people because they're, you know, celebrity movie stars or because they're super wealthy just no matter what they do with their wealth because I think we ought to try to encourage more people to act in that way.
Peter Singer