There has been a lot of talk of late about whether or not chimpanzees are, or should be counted as, persons. The most immediate occasion concerns a legal maneuver on the part of the Nonhuman Rights Project to get two chimpanzees to be recognized in law as persons. A group of philosophers and others have submitted an amicus brief in support of this motion, and a fortiori in support of the contention that no legally plausible understanding of “personhood” excludes chimpanzees. 

I have a lot of sympathy for the practical aims of the HNRP in this case. Given what we know about chimpanzees and the facts of the case at hand it seems likely that the two chimpanzees are being harmed and this should be rectified. However, I find the arguments of the amicus brief unpersuasive and a largely beside the point. Overall they display the penchant of philosophers to confuse the kinds of questions that interest philosophers with questions that are relevant to legal proceedings. I’ll say a few things here about a couple of examples. 

I tend to think the word “person” in these debates is always used to beg questions, and so looking to say what does or doesn’t constitute a “person” already muddies the water. What matters is this: does the law have good reasons to distinguish human beings from other animals? It seems to me the answer to this question is obviously yes, and it is equally obvious that this is so because of important differences between humans and other animals having to do with (again rather obvious) biological, and especially cognitive, differences between humans and other animals that manifest in a large number of ways in a large number of contexts. The use of the word “person” is best understood as a marker of these many differences. So understood, the exclusion of non-humans seem prima facie unobjectionable. 

Against this the philosophers recycle two rather bad arguments. One is that Darwin has taught us that there are no deep differences between species but instead that there are deep continuities. Putative lines between species vanish if we take a suitably historical perspective and consider the effects of constant evolutionary change. And so insisting “person” and “human” are co-extensive is bad metaphysics because “humans” cannot be precisely defined, and it’s bad ethics because humans are too much like chimpanzees (at least) to be put in their own moral category. 

But this is simply not to the point. Again, the question at hand is whether the law has good reason to distinguish humans from non-humans, not whether philosophers of biology trying to define “species” do. That there are presently manifest differences between chimpanzees (or any other non-human animals) and humans is quite plain, and distinguishing the two for every purpose for which the law needs to distinguish them is easily done. No one will be believed if they bring a chimpanzee to a park full of children and set it loose and then claim they mistook it for a human child when it maims someone. We do not need Darwin’s permission to say human children must be educated but not chimpanzees. So: the biological similarities between chimps and human as judged by a Darwinian perspective are not really relevant. The manifest behavioral and cognitive differences that matter to law are.

There is another way to try to blunt this last claim however, and this is point out that not all humans (currently or still or ever) have these traits. This move is meant to put deniers of chimpanzee personhood on the defensive. Either we deny personhood to some humans, or we weaken the membership requirements enough that some non-humans gain entry along with infants and the like. But this is also wrong. When we say that humans have X, Y, and Z and chimpanzees do not, we mean to qualify both claims with an implied “typically.” Say this out loud and certain kinds of philosophers will call you an “essentialist” and explain all the reasons why essentialism is wrong, and—again—all the Darwianian reasons why the concept of human (or chimpanzee) nature is bad biology and worse metaphysics, and why treating a baby human differently than a cognitively similar chimpanzee on account of the former being human is morally repugnant. But all this is once again to run together a number different issues. 

We don’t need a metaphysically robust account of essences or human nature to be able to list the typical cognitive abilities of mature humans and note the many ways in which they differ from those of chimpanzees. Nor do we need to settle the metaphysics to draw reasonable conclusions about what sorts of things contribute to the flourishing of each according to those abilities, or the resulting vulnerabilities to harm. Indeed, defenders of the chimps at the heart of the legal debate have no qualms about listing the needs of chimpanzees based on what is typical of chimpanzees. Yes, some humans are atypical in their cognitive abilities, but this is rightfully seen as a loss or a disability if it leads to a diminished quality of life. A similar level of cognitive ability is not seen as a loss or disability in chimpanzees if it is in fact quite typical of those animals—a chimpanzee’s quality of life does not suffer on account of its being a typical chimpanzee. So, as many people have argued, it simply a mistake to treat small children or the cognitively disabled as the moral equivalents of chimpanzees or dogs or whatever because of a supposed (I’m pretty sure the right word here is “imagined”) cognitive parity. We have moral duties of care for children that we don’t have for typically abled chimpanzees, regardless of their respective cognitive abilities, and the law is surely right to recognize these sorts of facts as well. Once again, using “person” as a marker for this complex of systematic and relevant differences seems unobjectionable.