We ought to consider the interests of animals because they have interests and it is unjustifiable to exclude them from the sphere of moral concern; to make this consideration depend on beneficial consequences for human beings is to accept the implication that the interests of animals do not warrant consideration for their own sakes.
Peter SingerWhat is there about the notion of a person, at law, that makes every living member of the species Homo sapiens a person, irrespective of their mental capacities, but excludes every nonhuman animal - again, irrespective of their mental capacities?
Peter SingerIf animals are no longer quite outside the moral sphere, they are still in a special section near the outer rim. Their interests are allowed to count only when they do not clash with human interests. If there is a clash - even a clash between a lifetime of suffering for a nonhuman animal and the gastronomic preference of a human being - the interests of the nonhuman are disregarded. The moral attitudes of the past are too deeply embedded in our thought and our practices to be upset by a mere change in our knowledge of ourselves and of other animals.
Peter SingerNo consideration at all is given to the interests of the "pests" - the very word "pest" seems to exclude any concern for the animals themselves. But the classification "pest" is our own, and a rabbit that is a pest is as capable of suffering, and as deserving of consideration, as a white rabbit who is a beloved companion animal.
Peter SingerAll the particular moral judgments we intuitively make are likely to derive from discarded religious systems, from warped views of sex and bodily functions, or from customs necessary for the survival of the group in social and economic circumstances that now lie in the distant past.
Peter SingerWithout in any way minimising the economic and psychological blow that people experience when they lose their jobs, the unemployed in affluent countries still have a safety net, in the form of social security payments, and usually free healthcare and free education for their children. They also have sanitation and safe drinking water.
Peter Singer