There are many books that have influenced the way I see the world. One that stands out is Animal Liberation (1975) by Peter Singer. Probably one of the most important books of the last 100 years, it expands our moral horizons beyond our own species and is thereby a major evolution in ethics. Singer was not the first philosopher to articulate the concept of animal rights. Over 200 years ago, Jeremy Bentham argued that many other species experience pain similar to human pain and that a "day may come when the rest of the animal creation may acquire those rights which never could have been withholden from them but by the hand of tyranny". He proposed that the capacity to suffer, not the ability to reason, should confer on other creatures the right to be spared pain.
Nor is Singer the last or most provocative thinker to the advance the rights of animals. With a glowing preface by African-American author Alice Walker, Marjorie Spiegel's book, The Dreaded Comparison - human and animal slavery (1988), compares the enslavement of animals on farms and in medical laboratories with the enslavement of black Americans.
Even more shocking, in his essay "Can the Treatment of Animals Be Compared to the Holocaust?" (2006), David Sztybel suggests that despite some obvious differences, the mass slaughter of animals is ethically analogous to the Holocaust in the scale of suffering involved, and that there are significant similarities between the human abuse of fellow animals and the Nazi abuse of fellow humans.
It was not until 1983 that I read Animal Liberation. Singer was the first person I had come across who voiced animal rights as a coherent moral philosophy and as a liberation movement on a par with the freedom struggles of women, black and gay people. He argued that the abuse of animals was motivated and justified by speciesism - a notion of human supremacism that presupposes that the intelligence and technological mastery of our species gives us the right to oppress and exploit other species, regardless of the suffering caused. He proposed that speciesism is a form of oppression, comparable with racism, misogyny and homophobia.
Singer identified sentience, including the capacity to experience pleasure and pain, as the common bond that unites animals, human and non-human. It follows logically, as well as ethically, that if sentient human beings have a right to be spared physical and psychological suffering, then this right should be extended to sentient non-human animals that share our capacity to suffer. Their abuse in farming, sport, entertainment and medical research involves the violation of their right, as fellow sentients, not to suffer pain and distress.
Singer's philosophical framework linked together, in one seamless whole, the moral basis for both animal rights and human rights: if thinking, feeling beings have a right to be spared pain, we have a duty to oppose the abuse of both humans and other animal species. In Singer's moral universe, cruelty is barbarism, whether it is inflicted on human or non-human animals. The campaigns for animal rights and human rights therefore share the same fundamental aim: a gentler, kinder world, based on compassion and without suffering.
These ideas were eye-openers. I had previously only ever understood the issue in terms of animal welfare and the prevention of cruelty. My response? I phased out eating meat, ditched my leather jacket and began rethinking my politics. I had long been a left-wing socialist and had embraced the green agenda. Singer reminded me: socialism and environmentalism are not ends in themselves. Although progressive ideologies and social systems are valuable enablers of liberation, they are merely a means to an end, which is to maximise happiness and minimise misery.
Abuses such as factory farming and anti-Semitism are wrong because they cause suffering, not for theoretical or ideological reasons. The same is true of imperialism, war, discrimination, unemployment, vivisection, slum housing, racism, and climate destruction. They result in pain, which is why ending them is moral and necessary.
From Singer's animal rights philosophy I extracted a renewed understanding that the ultimate aim of all progressive politics should be to halt bodily and mental suffering. Losing sight of this aim has led to left-wing horrors such as Stalinism, where liberty is sacrificed, terror excused and suffering rationalised for the sake of the bigger, ideological goal of socialism. Too often, the left is consumed by grandiose abstract ideas and political objectives, forgetting what ought to be its raison d'etre: love, compassion and a world where no being, strong or weak, suffers.
For more information about Peter Tatchell's human rights campaigns: http://www.petertatchell.net