Years and years ago, my brother was a vegetarian. Because I was an immature student I would tell him that he was participating in the mass murder of plants. It is not a particularly subtle or good argument against vegetarianism but it does raise what I think is a legitimate question about the reasons why we accord moral personality to some things and not others. We do so on the basis of the reactions whereby the other agent demonstrates to us a feeling that we identify with and empathise with. If I hit you, your reaction reminds me of what it is to be hit. If I shoot a pig, its squeel reminds me of what it is to be shot. Even those who advocate that we should give plants rights use this argument by suggesting that plants scream as their stalks are cut. This drives me onto a point of worry in terms of what is now called Animal Studies.
Animal Studies is a new field- spanning all the humanities. It looks at animals as interesting units. So a historian might write about the fate of dogs and horses in world war one as they were used for military reasons- a philosopher might consider the rights of animals and a literature theorist the division between humans and animals in literature. Reading an article in Chronicle which serves as an introduction to the field, despite the fact that as one commenter says it does not mention the leading philosopher of animal rights Peter Singer, something struck me. The problem with according animals rights or moral personality is not a problem about whether they should have rights or personality- ie it is not a problem about whether human life is preferable to animal life. Rather it is a distinct problem about the fact that the mind of an animal is unknowable: I presume to guess that you think similarly to me: so we would both abhore slavery even if it came with unlimited sufficiency- but I cannot do so with a pig.
This affects our moral judgements and our ability to judge for animals about what they would prefer in a given situation. Take the situation of a pig being fattened for slaughter. All human beings that I know would say that they object to that: they can see that the pleasure of more food and comfortable surroundings is being exchanged for an uncertain, painful and final future. We discount present happiness into the future: we do so with sadness too- studying for exams is no fun, but students do it to acheive a degree or qualification that will they hope benefit them. Are the same calculations made by pigs though? How do we know whether a pig would prefer to have an endless supply of food in exchange for a shortened life? The answer is that we do not know whether a pig would prefer that because we do not know what kind of idea of the future the pig has. We could imagine that the pig is a human being: but that seems to me to unwrite the whole idea of the animal having rights, the fundemental right is the right to define what is good for me.
There are two reasons why animal feelings are inaccessible to me whereas human feelings are not so inaccessible. The first is the obvious: I am a human so are you. Therefore when you and I come to the same situation we are likely to react in the same way. Despite our greater simularity this begs the same question though as my pig example- how do I know that I am not defining through my sympathy your good, how do I know that my morality is not moral but paternalistic. That is where the second key distinction comes in, language. You can tell me what you prefer in a given situation- you can inform me of what you see as the good and I can adjust my perceptions in response. Language is not a perfect tool of communication but it beats a grunt. The pig cannot tell me what it wants and therefore how can I presume to know what it wants- in that sense is it meaningless to talk about animal desires and animal wants, and therefore the rights to acheive them?
I don't say this to dismiss the whole idea of animal rights- others will know more and think more about this than me and may have answered these questions. But that is the central issue to me: defining animal rights means defining what is good for an animal and ultimately the internal consciousness of an animal is an undiscovered country to me. Its subjective impression of what it wants is something I do not know and therefore I cannot know if it would prefer say, a short life of abundant plenty followed by death or a longer life of scarcity but without the prospect of the farmer's knife. I know what I would prefer, but I don't think its my right to impose my preference on a pig, a chicken or anything else for that matter.