A little while back a mainstream media entity published a discussion on longevity between Aubrey de Grey of the SENS Research Foundation, an organization working on the foundation for rejuvenation biotechnology, and Walter Bortz, a long-time advocate for a better approach to health and aging, but a skeptic on the development of new and radically more effective ways to intervene in the aging process. This is a later opinion piece in which Bortz comments on the discussion and de Grey replies in the comments:
We had never met each other, but knew ourselves by reputation. Our interface is similar to one that exists between two senior gerontologists Steve Austad and Jay Olshansky. They have bet $1 million that someone will live to be 150 within their lifetimes. Austad bets "yea," Olshansky, "nay." Jay in fact argues that if we don't get a handle soon on our obesity epidemic we will all live less long than our parents.
De Grey actually pushed back from the immortality label, much preferring the more modest "rejuvenation" tag. His, and Austad's, argument simply put is: Given the rapid progress in molecular biology of the past two decades then it is logical to extrapolate to the conclusion that soon several decades may be added to our current estimate of a 120-year max lifespan.
I follow these various suggestions closely, but find their excitement to be curtailed by realism. My take on all of this is based on my devotion to the Second Law of Thermodynamics that roughly states everything in an open system goes inevitably to greater disorder due to heat loss and entropy. No exceptions allowed. Time has only one direction.
An important codicil to this resides in the fitness advocacy that I favor. This asserts that aging may be slowed but not arrested. Fitness confers a 30 year delay in decay. A fit person of 80 is biologically the same as the unfit person of 50. So De Grey and I agreed to disagree. I am secure in my advocacy of 100 healthy years that I insist is currently within our biologic and political realms. De Grey hopes for more.
I like to see myself as an optimist. Norman Cousins said that "no one is smart enough to be a pessimist," but optimism must be tempered always by reality. To me this means that the Second Law of Thermodynamics rules. Even rejuvenation must obey that law. There is no, and won't be, a perpetual motion machine. We, and everything else, wear out. Sci-fi is sci-fi.
It was indeed an enjoyable conversation. It had a few gaps, though, which didn't make it into the printed piece. One was that I never quite learned how the validity of the second law of thermodynamics as a reason why rejuvenation is fantasy can be reconciled with the fact that babies are born young.
As for Walter being an optimist, yes, that's also how Jay Olshansky likes to label himself. The most dangerous pessimists, in my view, are the ones who think of themselves as optimists, because they infer that anyone more optimistic than themselves is a fantasist and their work unworthy of study detailed enough to deliver accurate evaluation. But I'm sure we will meet again!
The second law of thermodynamics is mentioned, but I think that this is often misunderstood - even by scientists - and has little importance in considerations of aging and rejuvenation. It is perfectly possible to take an open system and impose order so as to reduce its level of entropy. This happens all the time, and we are surrounded by examples of it in practice, both in the natural world and in our technology. Repair is only one form of entropy reduction, but we humans manage well enough in any number of system.