I first encountered this quote from Bentham in Peter Singer’s seminal book, Animal Liberation. Singer is the Ira W. DeCamp Professor of Bioethics at Princeton University and Laureate Professor at the Centre for Applied Philosophy and Public Ethics at the University of Melbourne. And it made perfect sense to me: If a being has the ability to experience suffering, I reasoned, then I have no moral right to cause that being to do so.

But now, taking into account the thoughts of John Harris, Jared Taglialatela, and Brandon Keim, I have realized that drawing the line at suffering may not be inclusive enough, though that guideline may yet be salvaged.

Here is Harris’ thinking on the issue, taken from his book, The Value of Life (p.18):

“In order to value its own life a being would have to be aware that it has a life to value. This would at the very least require something like Locke's conception of self-consciousness, which involves a person's being able to 'consider itself as itself in different times and places'. Self-consciousness is not simple awareness, rather it is awareness of awareness.

To value its own life, a being would have to be aware of itself as an independent centre of consciousness, existing over time with a future that it was capable of envisaging and wishing to experience. Only if it could envisage the future could a being want life to go on, and so value its continued existence. The capacity to value existence in this sense is a fairly low-level capacity; it does not require rationality in any very sophisticated sense of the term, merely the ability to want to experience the future, or to want not to experience it and the awareness of those wants.”

Harris’ approach suggests that we should value a being as it values itself -- values its own life. And surely a being that values its own existence could experience psychological suffering at the prospect of its imminent death, which is enough to maintain Bentham’s guideline concerning suffering.

Harris then goes on to discuss personhood -- a subject that is of deep interest and engagement to me (pp. 18-9):

“We have at last arrived at a concept of the person. On the account that has emerged, a person will be any being capable of valuing its own existence. Apart from the advantage of its simplicity, this account has two other major advantages. The first is that it is value- and species-neutral. It does not imply that any particular kind of being or any particular mode of existence is more valuable than any other, so long as the individual in question can value its own existence. Once this threshold is crossed, no individual is more of a person or more valuable than any other.

This concept of the person sets out to identify which individuals and which forms of life have the value and importance that makes appropriate and justifies our according them the same concern, respect and protections as we grant to one another. And it tries to do so without begging any questions as to what sort of creatures that will be found to qualify. The second advantage is that it is capable of performing the two tasks we require of the concept of the person. These are that it should give us some grasp of why persons are valuable and make intelligible the moral difference between persons and other beings. The second task is that it should enable us, in principle, to tell persons from non-persons.”

This throws wide open the notions of ethical treatment and personhood.

As an aside, any definition of a person would almost certainly include the requirement of the ability to have conscious experiences. As Neuroscientist Christof Koch, chief scientific officer at the Allen Institute for Brain Science, says, "Even honeybees recognize individual faces, communicate the quality and location of food sources via waggle dances, and navigate complex mazes with the aid of cues stored in their short-term memory. If you blow a scent into their hive, they return to where they’ve previously encountered the odor. That’s associative memory. What is the simplest explanation for it? That consciousness extends to all these creatures, that it’s an imminent property of highly organized pieces of matter, such as brains."

​Clearly, we have evidence of consciousness existing along a continuum, among many species.

In his book Practical Ethics (1993), Peter Singer describes a person this way: " ... I propose to use 'person', in the sense of a rational self-conscious being." He also observes that "[K]illing a person who prefers to continue living is ... wrong, other things being equal." These observations are clearly compatible with Harris's valuation of a being in accordance with its value to itself.

He further notes a sort of being that would not qualify for personhood: "In contrast, beings who cannot see themselves as entities with a future cannot have any preferences about their own future existence."

So we have some sense of accord among these philosophers. But a question that often arises when discussing the notion of nonhuman personhood is this: Why bother?

Why work to declare any nonhuman species persons?

As Richard Dawkins puts it in his contribution to the book The Great Ape Project:

“It must be conceded that this book's proposal to admit great apes to the charmed circle of human privilege stands square in the discontinuous tradition. Albeit the gap has moved, the fundamental question is still 'Which side of the gap?' Regrettable as this is, as long as our social mores are governed by discontinuously minded lawyers and theologians, it is premature to advocate a quantitative, continuously distributed morality. Accordingly, I support the proposal for which this book stands.”

In other words, although where we draw the line remains an arbitrary judgment, he nonetheless finds the notion of declaring the other great apes nonhuman persons useful. (I say “other” because we are, taxonomically, African great apes ourselves.) Expanding the membership of personhood beyond our species is a way to get the attention of members of our species. It is a way of declaring that these other, nonhuman persons deserve our respect of their wishes and interests. But it need not be a black-and-white issue. Consider the following from an article by Brandon Keim, a freelance journalist who has thought and written extensively about personhood; here, he is commenting on the views of Jared Taglialatela, a Clayton State University primatologist who studies chimpanzee communication:

“To [Jared] Taglialatela, chimpanzee ‘personhood’ is a judgment that falls on a spectrum of cognitive and social characteristics — a spectrum of subtle gradations, one that doesn’t place humans above and outside the animal kingdom, but within it. Calling great apes ‘people’ is arbitrary and, in any case, not a black-and-white judgment. … Humans become just another species — and one tasked, by our own capacity for action and reflection, with responsibilities towards our animal kin.”

— Brandon Keim

Rethinking my own previous way of sussing out all of this, I find the notion of a continuum of personhood a compelling vision. Dawkins’ “quantitative, continuously distributed morality” fits quite well with Taglialatela and Keim’s vision of “a spectrum of subtle gradations, one that doesn’t place humans above and outside the animal kingdom, but within it,” in which “Humans become just another species.”

This vision of a continuum of personhood is also one upon which specific demarcations, while at least somewhat arbitrary, are nonetheless potentially useful. As Harris says, such a spectrum is value- and species-neutral; a being need not be a member of our species, homo sapiens sapiens (HSS) to be considered a person. In fact, a being need not even technically be alive, meaning that a technological being, possessing of no life, in a biological sense, could conceivably be thought of as a person, provided that it at least valued its own existence.

Embracing such a continuum means re-thinking how we treat and interact with other beings. In my estimation, it makes the moral demand that we use our own practices/habits and our technology to do as little harm as possible to any being that values its own existence.