Valuing Life on a Continuum

Avoid the seductiveness of oversimplified utilitarianism

Stephen Colbert: “Let’s go down the food chain here, um, can I eat a shrimp?”

Peter Singer: “I think maybe shrimps feel pain, maybe they don’t, I mean it’s not certain, but I’d say why not give it the benefit of the doubt?”

S.C.: “Where do you draw the line? Because I actually think that an ear of corn has a better chance of having a coherent thought than a shrimp.”

P.S.: “Well, a shrimp has a bit more complicated nervous system than an ear of corn, so that’s why I’d go for the corn rather than the shrimp.”

S.C.: “Aren’t you being animalist, kind of anti-vegetable, at this point?”

-from an appearance of Dr. Peter Singer on the Colbert Show on December 11, 2006

In 1979 the philosopher Peter Singer wrote Practical Ethics, a book on consequentialism — the idea that the outcome of one’s actions defines their morality, as opposed to having intrinsic value based on a set of commandments. The book was widely read and Singer assumed the role of preeminent Benthamite utilitarian. Singer’s bombshell was the assertion that there is no de facto reason to separate animals from humans when valuing life or placing a cost on suffering. Singer’s prior 1975 book Animal Liberation quickly became the bible of the animal rights movement and put him at the center of a thirty-year battle between animal rights activists and the scientific community. At first pass, few scientists would argue with Singer’s basic “anti-speciesist” stance, no more than they would question that Homo sapiens sits on the same evolutionary branch as primates. Singer also states in the preface of his book that ethics can only proceed on the basis of facts; that is to say, philosophy must be informed by science if it is to have worldly relevance. How, then, did Singer’s arguments provide scholarly justification for a generation of protests against animal experimentation for science?

Singer divides all organisms into three strata: self-conscious, conscious, and non-conscious. Singer includes humans, primates, and most mammals into the first category. Singer then asserts that the negative value of animal suffering is morally indistinguishable from human suffering, because we have no reasonable way to draw a difference. As for the relative value of human and animal lives, Singer suspends judgement. This key tenet of the equivalence animal and human suffering, along with a number of poignant examples of animal cruelty, has fueled the animal liberation movement since then.

And there is the difference: while Singer hesitates to place the experiences and lives of organisms into a hierarchy of value, most scientists do maintain a tacit hierarchy as part of their general ethical framework. Reflection on our daily lives reveals that most non-scientific people maintain a hierarchy as well. We kill bugs and other creepy crawlies without much as a thought; in fact we will take explicit satisfaction in swatting a mosquito that has just extracted a drop of blood from our flesh. Most of us will advocate the killing of a dog if it is to spare the maiming of a human child. This hierarchy is rarely stated explicitly. The most widely adopted code for experimental animal treatment, The Guide for the Care and Use of Laboratory Animals, defines, for purposes of its application, “laboratory animals” as those possessing vertebra. This is as crude as Singer’s self-conscious/merely conscious division of the animal kingdom (although a footnote reference within the Guide to another text on cephalod treatment alludes to the fact that vertebra possession may be a poor touchstone, octopi being notoriously intelligent).

Singer’s motivation for stopping his analysis of organism value at three basic tiers is that there is no good basis for making further judgments and that we are, as part of the judged, biased judges. It is clearly a very difficult and ambiguous challenge to determine what an animal is feeling or experiencing. The behavioral capabilities of a particular species are the subject of heated debate among neurobiologists and ethologists. However, difficult as it may be, valuing the experiences and lives of organisms must be attempted by any laboratory biologist in their everyday work. The classic question goes: “how many mice are worth the prospect of curing a fatal disease in twenty years time?” — but the more mundane question is something more like: “what particular animal should I use in this speculative experiment and how much discomfort of the animal is acceptable?” Answers to both questions require an organismic value judgment to be made.

Animal rights activism, at least the moderate kind, does provide a useful role in society, as a balancing force to the practical need for efficiency in the use of animals which has tended to drive humans to mistreat animals. The animal rights movement has driven reform of factory farming, the fur trade, killing for sport, and cosmetics testing. Monkeys are no longer treated as entirely expendable in research settings. The pain of lab animals, at least when expressed through humanlike behaviors that resonate with us emotionally, is minimized when possible. It would be an attractively simple solution to place all animals on the same moral plane and be done with it. However, in order to reconcile our desire to treat organisms with care and respect with our desire to advance the well being of human society, a more graduated view of organism life value is inevitable, tricky as it may be to form one. Hierarchies imply hard boundaries or absolute rankings which frequently fail to adequately describe the gray areas of life, so perhaps a more apt view is that the value of life runs along a continuum, in all likelihood with humans at the top of the continuum.

Singer observes that nervous systems are the primary determinant of an animal’s capacity to show suffering. Nervous systems are clearly also the primary determinant of an animal’s ability to exhibit other forms of behavior and cognition that may be accorded some kind of intrinsic value. As neuroscience progresses, holistic notions like consciousness and feeling are being prized apart into components, flavors, and sub-functions; behaviors are being deconstructed and correlated with specific events and loci within nervous systems. Neuroscience advances our understanding of what nervous systems do and how they do it, and in doing so, can help us build our continuum of organism value in order to make thorny decisions involving animals (including humans) in a consistent and prudent way.