Philosophy is not politics, and we do our best, within our all-too-human limitations, to seek the truth, not to score points against opponents. There… - Peter Singer

Living a minimally acceptable ethical life involves using a substantial part of our spare resources to make the world a better place. Living a fully ethical life involves doing the most good we can.

How far down the evolutionary scale shall we go? Shall we eat fish? What about shrimps? Oysters? To answer these questions we must bear in mind the central principle on which our concern for other beings is based. As I said … the only legitimate boundary to our concern for the interests of other beings is the point at which it is no longer accurate to say that the other being has interests. To have interests, in a strict, nonmetaphorical sense, a being must be capable of suffering or experiencing pleasure. If a being suffers, there can be no moral justification for disregarding that suffering, or for refusing to count it equally with the like suffering of any other being. But the converse of this is also true. If a being is not capable of suffering, or of enjoyment, there is nothing to take into account.

[One thing] underpins, makes consistent, and gives meaning to all our other activities on behalf of animals. This one thing is that we take responsibility for our own lives, and make them as free of cruelty as we can. The first step is that we cease to eat animals. Many people who are opposed to cruelty to animals draw the line at becoming a vegetarian. It was of such people that Oliver Goldsmith, the eighteenth-century humanitarian essayist, wrote: "They pity, and they eat the objects of their compassion."