The July 24, 2013 issue of Newsweek online featured a major story: "You can live forever. Is immortality plausible, or is it just quack science? Two experts face off."
Some editor was tantalized by the highway billboard of Prudential Life Insurance that proclaimed "the first person to live to be 150 is probably already in middle age." He sensed a controversy. Somehow he recruited two "experts" -- Aubrey De Grey, a new age gerontologist from Cambridge, and myself, a traditional Stanford-based geriatrician with 50 years of old patient care, 150+ scientific articles, eight books, and considerable administrative affiliation in my CV. A clash was hoped for.
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. Some new app such as stem cells, or telomere lengthening, or upgrade of free radical scavenging enzymes, etc. will fulfill the Fountain of Youth daydream. Patching Methusaleh.
I follow these various suggestions closely, but find their excitement to be curtailed by realism. I employ the phrase of my friend Ian Morrison "premature extrapolation." It is my sense that 2+2 will always equal 4 regardless of what any new age mathematician may hope for.
Another geriatrician friend is Dr. Steve Coles of UCLA, who is chief of the international register of super centenarians (those over 110). I had Steve lecture here at Stanford last year. He showed slides of his super-cents. The take-home message of his talk was "you really don't want to be 110+. "
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.
Physical immortality is a fantasy.