Animal Liberation is Human Liberation too. - Peter Singer

September 11, 2001, was just another day for most of the world’s desperately poor people, so presumably close to 30,000 children under five died from these causes on that day—about ten times the number of victims of the terrorist attacks. The publication of these figures did not lead to an avalanche of money for UNICEF or other aid agencies helping to reduce infant mortality. In the year 2000 Americans made private donations for foreign aid of all kinds totaling about $4 per person in extreme poverty, or roughly $20 per family. New Yorkers who were living in lower Manhattan on September 11, 2001, whether wealthy or not, were able to receive an average of $5,300 per family. The distance between these amounts encapsulates the way in which, for many people, the circle of concern for others stops at the boundaries of their own country—if it extends even that far.

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.

Since ancient times, philosophers have maintained that to strive too hard for one's own happiness is self-defeating.