Animal Rights and the "Argument from Marginal Cases"

It is often said that "animal rights" isn't about adding something new to our ethical discourses, but about exposing some of the flaws in our own assumptions and really getting at what conclusions logically follow from the beliefs we already have. The unfortunately named "argument from marginal cases" (AMC) is revolutionary in this sense.

"Marginal cases" are human animals who lack the cognitive capacity necessary to reasonably be held accountable for their actions - to be judged morally culpable - but who are still considered members of the moral community nonetheless. Human babies, some mentally handicapped individuals, and the mentally deranged are examples.  

David Graham uses the following hypothetical debate to illustrate the strength of the AMC.

Opponent of animal rights: How can you say that animals have rights? It's impossible.

Proponent of animal rights: Why?  

Opponent: For one thing, animals can't reason. They can't be held responsible for their actions. To have rights, you must have these capacities.  

Proponent: Wait a minute. Infants can't reason. Does that mean it's open season on babies?  

Opponent: Of course not. Infants will be able to reason someday. We must treat them as prospective rights-holders.  

Proponent: But what if the infant is terminally ill and has only six months to live? What about a person who was born with part of his brain missing and has the mental capacity of a pig? What about a senile person? Is it OK to kill, eat, and otherwise use these people for our own ends, just as we now use pigs?  

Opponent: Well . . . let me think about that.

What this exposes is that those who are owed certain kinds of treatment as a matter of ethics are not necessarily the same people who have ethical obligations to do or not do some action. 

Plato argued that when dealing with adults and ethics, one cannot teach, but only remind. One can't be taught an ethical obligation, in other words, but can be merely prompted to acknowledge some of their own unstated assumptions and the conclusions that follow. The AMC is an exceptional tool to better realize what our own beliefs entail.  

Our view of human infants is important here. As mentioned in the aforementioned hypothetical, people assume that "potential" is valid. However, the appeal to "potential" simply begs the question because we are treating an individual as though they were someone that they, in fact, are not. Logically, it would follow that we would be justified in treating a human adult as though she was already dead - she has the "potential" to be dead - and therefore using her as a forced organ donor now is ethically permissible.

We can dispense with "potential" by investigating our intuitions about why we believe we ought not to treat human babies solely as a means to our ends. Should I be prohibited from testing the toxicity of household cleaning products on a three year old child, even if it will yield tremendously beneficial results that will help others, because she is on track to becoming capable of understanding and reciprocating a moral obligation?

No, it is self-evident that this is not the reason why causing this child harm is immoral. Because it is "self-evident," no explanation is necessary; however, for clarity's sake - it is wrong because doing so would cause tremendous suffering and potentially kill her, and that is reason enough.   

The "argument from marginal cases" assumes that speciesism is not ethically defensible. Speciesism, according to Peter Singer, is "giving moral preference to the interests of members of one's own species, over identical interests of members of a different species, solely because [they are members] of your species."

Because mere biological facts like species (and race or sex) and group membership aren't ethically relevant, and therefore the AMC cannot be circumvented by assuming that I count simply because I am a member of the human group, "pure Aristotelian logic powers the Argument from Marginal Cases," argues Graham. "It demands simply that we treat like cases alike - or else cite a relevant difference between the cases."

Two choices present themselves. We can either bite the bullet - accept the conclusions that follow from the AMC, leaving our most needy, the severely senile, for example, out of the moral community entirely. Or, to use a not-animal-friendly metaphor, we can take the bull by the horns - confront the obvious flaws in some of our basic assumptions, acknowledge what our own beliefs demand of us, and act accordingly.

The logical basis for veganism is irrefutable, even if we only extend to nonhuman animals the (negative) right not to be harmed or killed unless for reasons of self-defense, until we resolve the problem presented by the AMC.