Could utilitarianism sanction "unjust" actions? A very common argument levelled against the utilitarian approach is that its insistence on looking only to the total amount of utility produced endorses all kinds of actions that seem intuitively to be unethical. For example, homeless people with no family or friends could be secretly snatched from the street, killed and their organs donated to save the lives of ten people who are in desperate need of new organs. On a strictly utilitarian basis this type of action is morally justified. The loss of one unit capable of experiencing happiness (the homeless person) is outweighed by the happiness gained by the ten ill people and their families as the spare organs become available. Our "common sense" morality tells us that there is something wrong with this type of action. Because of these unattractive possibilities, utilitarianism seems to be inadequate as a guide to morality. If this is the case, then Singer cannot use utilitarianism as a guide to our interaction with non-human animals.

What about rights and duties? The above criticism can be used to suggest that there are some other moral principles that are more acceptable than utilitarianism. Because of the problems with looking to the consequences and viewing utility as the only important consequence, other thinkers have argued that humans have duties towards each other (and perhaps the natural world) or that humans (and some animals) have rights. Such ideas have the advantage of avoiding the difficulties of utilitarianism. It would be possible to claim that humans have a duty to treat animals with respect and so claim that eating meat is morally wrong. It may also be claimed that animals have a right not to be eaten. The main problems that face these ideas are in the attempt to rationally justify them. Why should animals be treated with respect? Why should animals have rights? Which animals?

Specific criticisms of Singer's ideas

One specific criticism against Singer's ideas comes from what can be very loosely described as the "Deep Ecology" movement. This philosophical position is one that attempts to locate intrinsic value in nature. In other words, deep ecology wants to show that nature (including non-human animals) is morally valuable in its own right. A leopard is valuable not because humans find it very beautiful to look at, not because it is an endangered species, but simply because it is a leopard. Its value exists independently of any pleasure or benefit it provides to humans and, perhaps more controversially, its value exists even in the absence of a human to value it. This perspective sees Singer's utilitarianism as a philosophy that ignores the intrinsic value of animals. It only deals with those beings physically capable of suffering. All non-sentient creatures are disregarded. Non-human animals have a moral relevance only if they are capable of suffering. It is also worth noting that Singer's utilitarianism would sanction the suffering of a small number of non-human animals if the overall total of utility were increased. For deep ecologists, this is simply not good enough. They argue that Singer's utilitarianism, because of its failure to recognise the intrinsic value of non-human animals, perpetuates the very same human-centred worldview that encourages the exploitation and degradation of the non-human world.

The deep ecologists do have a point here. Singer's utilitarian approach, based on the assumption that suffering is to be avoided, doesn't necessarily have to lead to vegetarianism. Imagine a slaughterhouse where all the animals were unaware of their imminent death (and so were not distressed), and where death was completely pain free (assuming this could be proven). It would be very difficult for Singer to condemn this.

Some deep ecologists also question Singer's (and others) idea that animal liberation is a good idea. Most deep ecologists view the stability, diversity and beauty of the ecosystem as the goal of ethics. Humans ought to act in ways that promote this goal. Releasing all the captive farm animals and abolishing the practice of eating meat would almost certainly upset the fragile balance of an already damaged ecosystem. For these thinkers, mass animal liberation is unethical.

There is also an extreme position with the very impressive title of biocentric egalitarianism. This position states that anything that is alive should be treated with equal moral consideration. In its extreme and perhaps somewhat caricatured form, this position would argue that a blade of grass should be given the same moral consideration as a leopard or a human. From this perspective, Singer's ideas are not radical enough.