Who did not feel the ‘yuck’ factor when they first saw the picture of a hairless mouse with what looked like a human ear growing on its back, circulated around the world’s media? It wasn’t actually an example of gene manipulation but rather a demonstration of how an animal could be a surrogate host for growing an implanted bioframe.29 But it certainly looked like a hu-mouse! Our revulsion was not simply because it was a weird image. Rather, we felt simultaneously sick and fascinated because the prospect of human–animal hybrids violates the essentialist view of the world that we developed naturally as children. When I was preparing this chapter, my youngest daughter looked over my shoulder and saw the image of the mouse with the human ear. At first she let out an audible ‘yugh!’ Then she asked if it could hear better. Apparently she is still telling her classmates about it.
FIG. 13: Mouse with an implanted bioframe. Many people have misinterpreted this image as an example of genetic engineering. © BRITISH BROADCASTING CORPORATION.
MAY THE FORCE BE WITH YOU
Related to the notion of essence is the idea of a life force, something that is in living animals but not in dead ones. This is vitalism, an ancient belief that the body is motivated by an inner energy. Up until the nineteenth century, this was recognized in the West as the ‘élan vital’, a vital force that does not obey the known laws of physics and chemistry.30 In most conceptions of a life force, it is equated with the unique identity of the individual. In other words, it is the essential soul that many believe inhabits our bodies but departs on death to move on to another dimension/body/location/time (delete terms as appropriate depending on your afterlife belief system).
Although we cannot see the energy generated in our bodies, most of us intuitively feel it is there – not within every living cell, as Krebs’s cycle describes it, but rather as a unified whole thing that animates the body. I can relate to why people think this. On occasion, I have had to kill animals, either for food or because they have become a nuisance. I live in the country and raise my own chickens for the table. When they are ready, I pull their necks. When you kill a largish animal up close, as opposed to squashing a fly with a rolled-up newspaper, you can experience a sense that something leaves the body. A living entity that a moment ago was animated, flapping around and agitated, is now still. But there seems to be more involved than just an absence of movement.
I have seen a number of corpses in the dissection room, but I have not watched someone die in front of me. However, I have talked to friends and colleagues who have been at the bedside of a dying person, and they often report that something seems to depart. So far no one has told me that they actually saw something leave a body. Rather, they get a feeling that someone or something has left. Maybe this is what our minds create in order to makes sense of the change in the situation: suddenly there is one less person in the room. How can there be one person less in the room unless someone has left?
In popular culture, the moment of death is often depicted as a life force or energy leaving the body like some semitransparent copy of the person. This notion may be purely psychological, but there are many people who think a tangible soul exits the body at death.31 In 1907 Dr Duncan Macdougall of Massachusetts reported that the soul weighs precisely twenty-one grams based on his careful measurement of six dying patients on a set of industrial scales.32 His findings were and have since been treated with much scepticism, with alternative explanations ranging from fraud to methodological weakness. Because the weight loss was not reliable or replicable, his findings were unscientific. When he was prevented from further human studies, Dr Macdougall moved on to dogs that he sacrificed in his scientific search for the soul. The results of these studies showed no evidence of a weight loss at the time of death. Undeterred, Macdougall interpreted this as evidence for the Christian belief that animals don’t have souls. In which case the word ‘animal’ is inappropriate, as it comes from the Latin anima, for soul.
Scientifically, death is another continuous stage of life. At death, the meat machine no longer functions as a unified system and begins to decompose. It starts to disassemble itself. In the absence of oxygen, the cells start to die. Krebs’s metabolic cycle shuts down, and the system starts to go into reverse. The bacteria colonies that once helped to sustain life now begin to break the body down. Like opportunistic looters, they requisition various material substances to embark on their own life cycles in isolate. It’s like the breakup of an army. Once the battle is over, the individual soldiers take what they can and then head off. The state of death is simply the process of life in different directions. With the defence systems down, all manner of microbe, insect, and beast plunder the body for resources. If we could record and play our lives out as one of those time-lapse movies of decaying fruits and animals, we would realize that composition and decomposition are continuous.
Such an account is neither comforting nor acceptable for most. Where has the person gone in this version? The body remains, but the person is absent. A departing life force that energized the body is the only sensible explanation for most people. The mind–body dualism we intuit when we are alive explains to us what happens when we are dead. And, like dualism, the notion of a vital energy inhabiting the body is a concept that emerges early.
Young children understand life in terms of a vital energy necessary for keeping the body going.33 In one investigation, children were asked different biological questions, such as, ‘Why do we breathe?’ To help them answer, the researchers offered the children three types of explanation: those based on mental goals (because we want to feel good), mechanical explanations (because the lungs take in oxygen and change it into useless carbon dioxide), or vitalistic explanations (because our chest takes vital power from the air). By six years of age, most children endorsed the vitalistic reasons, whereas older children and adults selected the mechanistic accounts. Education may have taught them about oxygen and carbon monoxide, but the explanation based on vital energy was the default position of younger children. Some children talked about blood carrying energy to the hands in order to make them move. Education provides us with new frameworks of explanation, but as we saw with naive theories of gravity and other intuitive models of the world, it’s not clear that earlier ways of thinking are abandoned. An enduring vital force seems a plausible explanation for life.
The concept of enduring life energy is not entirely flaky. A living body does generate energy in that it converts energy from one source into another. This is what metabolism is. Energy is never lost. This is the first law of thermodynamics, discovered over the last three hundred years. Energy cannot be lost but rather changes state. While very few of us are knowledgeable about the laws of thermodynamics, for many the transition from life to death is simply the movement of an energy source from one state to another. Many adults who are ignorant of the biological facts regarding metabolism and energy can nevertheless still conceive of some force that resides in a living thing but moves on at the point of death. We are intuitive vitalists.
But children do not start off as vitalists. The questions confuse them because they have not yet begun to think about their own bodies as separate from their minds. This may explain why they have a problem understanding death, as we saw in the last chapter. When five-year-old children were sorted into those who thought in terms of vital life forces and those who did not, the vitalist children were the ones who understood that death is irreversible, inevitable, and universal and applies only to living things.34 Younger, novitalist children were just confused. So an emerging naive vitalism helps children to appreciate the nature of death as final and something that happens to everyone. Intutive theories don’t have to be scientifically accurate to be useful.