The author quoted here has written a number of interesting posts on aspects of philosophical thinking pertinent to rejuvenation biotechnology and the goal of bringing an end to the pain and suffering caused by aging. While from my position I see that no more justification is needed for working to greatly lengthen healthy life spans than the fact that some of us want to do it, and that it will make the world a better place for all if successful, there are always those who want more of a story than that. There is of course a small mountain of literature that does indeed go far beyond my brief motivations, but I suspect that this is the case because writing and thinking is easy. Building new technology is much harder, and so, inevitably, there is far more discussion than action for rejuvenation research, just as is the case for every challenging form of human endeavor.
A friend recently recommended a paper by Davide Sisto entitled "Moral Evil or Sculptor of the Living? Death and the Identity of the Subject". Unfortunately I was slightly underwhelmed. While it does contain an interesting metaphor - namely: that we should view death as a valuable 'sculptor' of our identities - it presents this metaphor in a way that bothers me. It presents it as part of critique of the contemporary (transhumanist) view of death as a biological problem that can be solved with the right the technological fix. Indeed, it tries to suggest that those who favour radical life extension are beholden to an absurd metaphysics of death. Now, to the extent that certain transhumanists believe we can achieve a genuine immortality - i.e. an existence free from all prospect of death - I might be inclined to agree that there is something absurd in their views. But I'm not convinced that this fairly represents the views of anti-ageing gurus like Aubrey de Grey. I think they have a much more modest, and I would suggest sensible, view: that human life can be prolonged far beyond the current limits without thereby causing us to lose something of tremendous value to our sense of self.
Ostensibly, Sisto's paper attempts to contrast two views of death. The first view of death is the one that has now started to dominate in the secular, medicalised world. It is the view of death as something that is part of the current natural order. When Christianity dominated the western world, death was viewed as a consequence of original sin. As the Christian view slowly receded into the background, it was replaced by a biological and medical view of death. Death was a consequence of the current natural order - an unfortunate result of biological decay. Our cells slowly degrade and denature themselves. The degradation eventually reaches a critical point at which our metabolically maintained homeostasis breaks down. This results in our deaths (though the precise markers of biological death are somewhat disputed - 'brain death' is the currently preferred view). This naturalised view of death is very different from the old Christian ideal, closely joined to something that the bioethicist Daniel Callahan calls 'technological monism', the belief that everything in the world is, in principle if not in fact, within the reach of our technology. Technological monism suggests that death is not a fixed and immutable feature of our existence. It is something we can - with the right kind of intervention - prevent. We can slow down and reverse our biological ageing. We can preserve our identities for longer than we previously hoped. This 'technologised' view of the world lends support to the belief that death is a moral evil: it is something within our power to fix, and hence we are, morally speaking, on the hook for allowing it to continue.
There is much more in Sisto's discussion of the 'death as moral evil' view, but I think the preceding summary captures the gist. The main argumentative thrust of Sisto's paper comes from the contrast he draws between this view and his own preferred view of 'death as a sculptor'. The essence of this view is that death is not separable from life contrary to what the technological monists want to believe. They want to have a life without death. But this is not possible. Death is a necessary part of life as a whole. It is what gives shape, direction and, above all else, a sense of identity to life. Sisto explains this symbolic idea by reference to the biological process of apoptosis, or programmed cell death. This is a highly regulated biological process whereby cells within an organisms body will kill themselves off when they are no longer necessary for some particular tissue. Sisto makes this example do a lot of work. He argues that the apoptotic process is essential to biological life; that it is what gives the organism its unique identity. He believes that this supports his contention that life and death are inseparable. Death is built into the biological process of being alive. Once you die, your life becomes characterised by the path you took through the space of possible choices. This path contains all your accomplishments and failures, all your loves and losses, all your aspirations and fears. It effectively constitutes your identity. Without death, this lifeline would lose its unique identity. If you had infinite time to play around in, you could travel back down some other paths; take routes through life that you hadn't taken before. Death - the end of choice-making - is what sculpts you from the void of possibilities. I find this metaphor to be very evocative. It really does give you an interesting perspective on the nature of death. But I don't think it is as interesting and useful as Sisto supposes.