Soulless Bodies [Archives:2005/897/Health]

November 24 2005

The world's leading scholar in artificial intelligence once described people as machines made of meat. This nicely captures the consensus in the fields of psychology and neuroscience, which tell us that our mental lives are the products of our physical brains, and that these brains are shaped not by a divine creator, but by the blind process of natural selection.

But, with the exception of a small minority of philosophers and scientists, nobody takes this view seriously. It is offensive. It violates the tenets of every religion, and it conflicts with common sense. We do not feel, after all, that we are just material bodies, mere flesh. Instead, we occupy our bodies. We own them. We are spontaneously drawn to the view defended by Rene Descartes: We are natural-born dualists, so we see bodies and souls as separate.

This dualism has significant consequences for how we think, act, and feel. The philosopher Peter Singer discusses the notion of a moral circle – the circle of things that matter to us, that have moral significance. This circle can be very small, including just your kin and those with whom you interact on a daily basis, or it can be extremely broad, including all humans, but also fetuses, animals, plants, and even the earth itself. For most of us, the circle is mid-sized, and working out its precise boundaries – does it include stem cells, for instance? – can be a source of anguish and conflict.

The nature of these boundaries is related to our common-sense view that some objects have souls and others do not. If one attributes a soul to something, then it has value; if one sees something as a mere body, it does not. This is often explicit; historically, debates about abortion, for example, are often framed in terms of the question: When does the soul enter the body?

This reasoning can apply as well to how we regard adults. Normally, when we interact with others we see them as both body and soul. We appreciate that they have beliefs, desires, and consciousness, and we recognize that they are solid physical things that take up space and are subject to gravity.

Both stances coexist well enough in the normal course of things. But when we emphasize one perspective over another, there are moral consequences. Social psychologists have shown that simply getting an experimental subject to take another person's perspective will make the subject care more about the person and be more likely to help. Focusing on the soul, then, leads to moral concern, and can expand the moral circle.

The opposite can occur when someone is viewed solely as a body, and one emotion that supports this outcome is disgust. The psychologist Paul Rozin has shown how disgust, as Charles Darwin first noted, is an evolutionary adaptation that deters us from bad meat, so it is naturally triggered by animals and animal waste products. But disgust can readily extend to people. People, after all, are made of meat. Hence, every movement designed to stigmatize or malign some group – Jews, blacks, gays, the poor, women, and so on – has used disgust. Once a group of people is viewed as disgusting, attention shifts away from them as moral individuals. They become soulless bodies, and the moral circle closes in to exclude them.

Our reaction to soulless bodies is well illustrated in a story told about Descartes after he died. It was known that Descartes had an illegitimate daughter, Francine, who died when she was five years old. According to the story, Descartes was so struck with grief that he created an automaton, a mechanical doll, built to appear identical to his dead daughter. The two were inseparable. When Descartes crossed the Holland Sea, he kept the doll in a small trunk in his cabin. Curious about the contents of the trunk, the captain of the ship crept down to Descartes' cabin one night and opened it. To his horror, the robot Francine arose. The captain, struck with revulsion, grabbed her, dragged her up to the deck of the ship, and threw her overboard.

This story captures how disturbing – in some cases, revolting – we find a body without a soul, and it embodies the emotional pull that our common-sense dualism often has. But it also raises a serious problem. Science tells us that common-sense dualism is wrong. There is no consensus as to precisely how mental life emerges from a physical brain, but there is no doubt that this is its source. Thus, if a “soul” means something immaterial and immortal, then it does not exist. All of us are soulless bodies, no less than the robot Francine.

This is perhaps the main reason why the scientific rejection of dualism may be so hard to swallow: it seems to diminish the moral status of people. If we are to accept scientific facts, we need to construct morality on a new foundation, one without souls.

Paul Bloom is Professor of Psychology, Yale University.

Copyright: Project Syndicate, 2005.