Until relatively recently, ethics has been a subject involving only human persons. Whether the issue concerns euthanasia, pornography, capital punishment, or world hunger, only human persons are involved. Since then, moral issues have arisen that involve not only human persons, but also non-human animals. This is a significant change, because the ethics involving only human persons is ill-adapted for problems involving not only them, but also non-human animals. In this paper, I argue that the traditional ethics is inadequate for solving the problem of animal research and non-vegetarianism, and that arguments trying to show that animals can be sacrificed in experiments in order to save human lives is inconclusive.
There are three different views on the moral status of non-human animals. The first is the speciesist view that only human beings have moral status. The second view is the anti-speciesist view according to which human and non-human animals have equal moral status. Both views hold that moral status is an all-or-nothing matter. In contrast, the third view holds that moral status is a-matter-of-degree, and that human and non-human animals have moral status, or intrinsic value, but to different degrees. On this view, moral status, or intrinsic value, of an animal is dependent on, and derived from, its capacity to have a rich life, which is in turn dependent on its experiential capacity. Given that human beings have the capacity to a richer life than other animals, they also have higher intrinsic value or moral status. Similarly, mammals also have higher intrinsic value than birds, which in turn would have higher intrinsic value than reptiles, which has higher intrinsic value than fish, shrimps, etc. I claim that the "matter-of-degree" view is the only plausible view on the comparative moral status between humans and non-humans.
However, this view leads to a problem. If we can save either (1) a human being from injury, or (2) a dog from death, but not both, which should we save? This is a different problem from the traditional problems in which a human being's claim is compared with the claim of another human being or human beings, because in these problems only the relative importance of the competing claims are at issue. Thus, in deciding whether people have the right to defame others as a special case of right to free speech, for instance, we take into account the pros and cons of allowing defamation versus the pros and cons of prohibiting defamation. In other words, we have to weigh and compare the competing claims of potential defamers versus those of potential victims. However, in the case of choosing to save either a human being from injury, or a dog from death, an extra consideration is in play, namely, the intrinsic value of the human versus the ( lower) intrinsic value of the dog. But the problem due to this extra "variable" seems to have no solution, because there is at present no ethical calculus or any conceptual schemes by which to compare the lesser claim of a human being and the greater claim of a lesser entity. Thus, if we compare (1) a human being's claim to the taste of a cow's meat, and (2) a cow's claim to life, we do not know how to make the comparison, because (1) and (2) are incommensurable.
To use an analogy, we can solve an equation with one variable (e. g., 2x+4=8), but cannot solve an equation with two variables (e.g., 2x+y+4=8), because there is one unknown too many. The moral analogue in the issue of animal rights is as follows. We can solve the problem of competing claim s in which two entities of different intrinsic value have claims of the same type. (We know we should save a human person's life rather than a dog's life, if we can only save one of them.) Moreover, we can solve the problem in which two entities of the same intrinsic value have claims of different type and different importance. (We should save a stranger from dying, rather than another stranger from injury.) However, we cannot solve the problem in which two entities of different intrinsic value compete for claims of contrary importance－that is, when a greater entity makes a lesser claim whereas a lesser entity makes a greater claim, because there is one unknown too many. (Thus, the utilitarian axiom that every person is to count for one is not only important in its own right, but is also a vital premise without which no maximization of utility could possibly begin. For by assuming that everyone is equal, utilitarianism assumes everyone's intrinsic value to be equal. This allows utilitarianism to hold "one variable" constant, and thereby in effect eliminate it from "the equation. ")
Speciesists only focus on the relative moral status (or intrinsic value) between humans and non-humans, whereas anti-speciesists stress the difference in intrinsic value between humans and non-humans. The truth, however, is that we have to take both variables into account, and yet there seems no way to combine both variables in the issue of non-vegetarianism. To give it a name, call this the two-variable problem.
In many cases of animal experimentation, the two-variable problem has no relevance, since by sacrificing the lives of a relatively small number of non-human mammals, we can prevent the mortality (and morbidity) of a greater number of human beings. It looks as though we have a net gain both in terms of lives as well as in terms of intrinsic value. But there lurks the question as to whether non- human animals have rights in general, and the right to life, in particular. If non-human animals have the right to life, then we are morally prohibited from using them as materials for experimentation, or as a source of food. On the other hand, if they don't have such a right, (though it does not mean we can therefore treat them in whatever way we like) it would seem to be justifiable to sacrifice them for experiments that can save many more human lives.
However, I argue that to answer the question whether animals have the right to life, we are faced with two major hurdles. First, we do not know what would constitute the necessary and sufficient conditions for having the right to life. Second, the intrinsic value from lowly creatures such as shrimps and fish to homo sapiens represents a continuous spectrum. To determine which type of creatures would have the right to life, and which would not, will surely involve a certain degree of arbitrariness. Since arbitrary solutions are not good philosophical solutions, animal rights issues as well as other issues have remained unsolved. These include the problem of personal identity, in which memory is a matter of degree whereas personal identity is all-or-nothing. The problem of whether a fetus is a person is another instance: A fetus grows continuously, but whether it is a person is supposed to be an all-or-nothing matter. Finally, the search for a definition of knowledge is another example. Knowledge is supposed to be all -or- nothing, but the justification of belief is a matter of degree.
I try to unveil the deeper structure of the problem of animal rights. As I said, those who accept the all-or-nothing views would have an easier dealing with the issue of animal rights. For if speciesism is correct, we can feed on animals, and use them for experimentation. If, on the other hand, anti-speciesism is correct, non-vegetarianism is forced on us, and animal experimentation must be banned. This is because in assuming either that non-human animals have intrinsic value equal to that of human persons, or that they have no intrinsic value at all, the two-variable problem is thereby reduced to a one-variable problem, which is solvable. But such reduction is premised upon implausible all -or-nothing views.
However, since speciesism and anti-speciesism are both implausible, the fact that the issues of animal rights would have been solvable if they were plausible is unhelpful. I don't know whether－nor do I suppose－that the problems of animal rights are in the end unsolvable. But I hope to have shown why there appears to be no satisfactory solution to these problems, at least as at present.
One reason why all -or- nothing views fail is that the moral reality is messier and more complex than they portray. In philosophy, views that take short cuts (e.g., some forms of reductionism) often achieve solution s by cutting the reality down in size or scope. The residual reality is manageable. But the desire for solutions and simplicity is satisfied at great costs, because the problem attacked is no longer the original issue.
Moreover, as Thomas Nagel observes, "[s] implicity and elegance are never reasons to think that a philosophical theory is true." Perhaps, as Nagel also points out, "one should trust problems over solutions, ... and pluralistic discord over systematic harmony." At the very least, Nagel seems to be correct about the issue of animal rights. For the all-or-nothing views are forms of reductionism that cut down the moral reality in size, that is, by cutting down a two-dimensional issue into a one-dimensional one.