The most compelling reason not to eat meat is not because it involves killing animals but because it so often involves causing animals to suffer, especially in factory farming. From this point of view there might be nothing wrong with eating free range chicken (because their lives are not miserable) or shrimp (if they are incapable of feeling pain). But as Peter Singer argues, causing unecessary suffering seems wrong. If some factory farming were the only way for some people to get enough iron, then it might be a tough call. But I doubt it is, and if I am wrong about this the argument still applies to many of us who do have easy alternatives. And causing unecessary suffering seems wrong even if the perpetrators are acting perfectly naturally.

The main way we cause pain to aminals is through the way we raise them in factory farms, so even if plants could feel pain (though like Richard, I bet they don't), we might be able to grow and harvest them without causing them any more pain than, say, we cause a free-range chicken. But if forcing them to grow in those straight rows causes them severe and prolonged distress....

I agree with Alex that animals are not morally accountable: they cannot be morally blameworthy (or praiseworthy). What is harder to explain is why we don't have a responsibility to prevent animals from hurting each other. This is an unnatural thought, yet perhaps technically we would have this responsibility, if we could also find an alternative diet for the natural carnivores. But given how awful is our own treatment of animals, we should perhaps concentrate on getting our own act together first.

This is a difficult question that understandably raises strong emotions. Some animal research has yielded significant benefit to humans, in drug development and in many other areas. But these human benefits have been purchased at the cost of animal harms, and it is natural to worry whether this is fair. Some people are reassured about the morality of animal experimentation by the fact that we kill so many more animals for meat than we do for research, or by the fact that more rodents are killed by cats than by scientists. But it is not clear that we should be morally reassured by these facts. Some would argue that even though animal suffering is bad and morally significant, animal death is does not have the same moral significance as human death, because of various abilities that humans have to conceptualise and to anticipate that animals lack. So one might be able to justify killing animals in experiments, if their suffering is sufficiently low. (Similarly, one might think that it is morally...

There is a story about someone who came up to a well-known moral philosopher in a restaurant and asked him what he thought about the arguments for vegetarianism. "I've actually thought quite a bit about some of those arguments, and I'm half-convinced by them", he replied. "So I don't eat meat for lunch."

I know of no good argument for the conclusion that animals cannot feel pain, and given the behavioral and physiological similarities between us and some animals the evidence seems very strong that some do. A biologist friend of mine told me about an experiement with, yes, rats. These rats had severe arthritis, a condition very painful in humans. They were given a choice between plain water and water laced with a tasteless drug (tylenol, perhaps) that does nothing to improve the arthritis, but in humans reduces pain. The rats quickly came to prefer the water with the pain-killer. This is no proof that rats feel pain, but it is a telling argument. And remember that you have no proof, in the strong sense of that term, that people other than yourself feel pain either.