Having this last month August indulged in some perspicuous articles by the late Bernard Williams (heartily recommended) concerning Problems of the Self; bumping into a few lectures by Yale philosophy professor Shelly Kagan on the prospects of dualism vs. physicalism; and finally, contemplating the premises behind the upcoming film 'Surrogates' starring Bruce Willis, I am now thinking about what it means that humans die.
Here is how I get there. Many will be familiar with the idea behind the featured cartoon. The 'brain in a vat' puzzle has gained currency not least with the recent work of Hilary Putnam. According to Wikipedia, guardians of all sacred knowledge, the idea was first proposed by Descartes. My guess is this is also the premise underwriting the new Willis movie. For the unacquainted, its prevailing question (to which the above cartoon draws attention) is whether we humans are anything other than our brains. Suppose scientists preserve your brain in a vat. They find a way to connect it up so that the brain receives the very same physical impulses as it does from the outside world when contained in the skull. The argument is that your brain would not recognise the difference between the sensation of walking in the sun and the actual bodily act itself; the physical impulses themselves subtract out, and the brain has nothing left to learn or experience. Many types of physicalism rest on this conclusion. The very concept of a human personal identity that is apart from the neuroscience of our brains is an illusion. You = your brain. Therefore, the 'brain in a vat' scenario is conceivable.
The thought experiment is usually applied to debates over scepticism about propositional truths, i.e. how can we ever be sure reality is not an illusion? Rather than go there, I think the corollary observation about what this means for human personal identity is deeply intriguing. Take your best friend. The question to pose is twofold. First we ask what she is: is she her brain? Or is she the projection of your own brain? The latter is solipsism: the belief that one's mind projects all that there is, ergo there is only one mind, yours, and therefore everything else is an illusion. It should be recognised that physicalists are not condemned to such foolishness. They may say 'yes' to the former question, but then suppose this is the case for every brain, and therefore for every person, and so avoid the solipsist trap.
Even so, the fate of personal identity is, for the physicalist, ultimately and inextricably bound up in the fate of the human brain. If the brain dies, the identity of a person in an important sense dies as well. One can certainly remember about that deceased person, and say that his personal identity 'lives on' in memory. But the truth is that aside from this memory, the person does not live on in any meaningful sense. He is dead. Nothing survives. The terminus of personal identity arrives following the death of what makes personal identity what it is. Which is, of course, only the body itself.
Grant this point for the moment. The next thing to ask is this: what if we could preserve or sustain the brain ad infinitum? What if the 'brain in a vat' scenario proved successful? The trailer anticipating the new 'Surrogates' movie suggests this possibility. Let us suppose we could hook your brain up now and let you live through a surrogate, and without the fear or threat of death. You could take on any persona. You could do whatever you truly want. Forgive for a moment that this would probably amount to utter chaos and disorder; that the globe itself would not be able to sustain it, seeing as we would probably lack the resources necessary to give the earth a surrogate as well. These matters set aside, the real question, the theological question is this: do we miss out on anything? do 'we' fail to participate in the reality which God has created?
My immediate answer is adamantly yes. We do. We miss out. Not on trivial matters either. The best analogy I can come up with is this: it is like the child who watches TV twelve uninterrupted hours on a gorgeously warm Saturday. We want to scream NO! Tear apart the blinds. Pull out the cords. Let the glare of a burning sun flood the room. Like this, only infinitely worse, is living a reality that is not real, a brain in a vat. But this gets me thinking some more...
For my 'spiritual cause' is not against the possible development of this kind of technology. We creatures never fall short of imagining new ways to undo our creatureliness. This would just add to the list. No, my business is rather with what this kind of thinking about personal identity appears to profess. The more I have thought about it, the more I have sensed the physicalist position is as paradoxical as it is troubling. It is troubling for obvious reasons. But it is paradoxical in this trouble. We often ascribe doom and gloom to physicalism, as though it accepted death without holding out on the hope of an afterlife. But the thing to see is that physicalism rests not on a cynical and dismissive view of any afterlife, but on an even more audacious and disturbing confidence in the scientific power to preserve life.
And this leads me to think the following. It is essential to who we are as creatures that we live with the prospect of death, and that we also die. To live a reality in which we do not is not to live in the reality in which we find ourselves. There is something to be said about eternal life. But whatever it is, it must follow the truth.
That truth is that humans die.