The “Death is Inevitable, Why Bother?” Argument
It might be inevitable that everyone dies eventually, but that doesn’t actually matter as to whether or not rejuvenation is worth pursuing.
Getting to the heart of this particular argument against life extension
There’s a fundamental similarity between the questions “Why rejuvenate your body if it’s going to die anyway one day?” and “Why clean your house if it’s going to crumble to dust one day?” An obvious answer to the latter question would be: “Because in the meantime, I’m going to live in that house, and for as long as I do, I’d like it to be clean.” This makes for a pretty accurate answer to the first question as well, so long as you replace “house” with “body”.
The implied assumption behind this concept seems to be that, as long as life doesn’t last forever, improving its quality and quantity is pointless. (It doesn’t make much sense to distinguish between quality and quantity in the case of life, because as we have discussed elsewhere, it really isn’t possible to extend the average lifespan without significantly improving health and vice versa.)
If this assumption were true, it would also apply to many other commonplace things and situations that we wouldn’t ever dream of considering pointless: if death is inevitable, why get a flu shot? If death is inevitable, why undergo heart surgery? If death is inevitable, why looking before crossing the street? If death is inevitable, why eat? And so on.
Even if death is inevitable, that is no reason not to develop life extension technology
The answer to all these questions is the same: for as long as we’re going to be alive, we’d like to make our lives as enjoyable as possible; and not only do all those things improve the quality of our lives, they make our lives last longer than they would otherwise. Maybe it won’t last forever, but a longer, more enjoyable life seems preferable to a shorter, more unpleasant life.
As an extreme example, if improving and extending a finite life is pointless, then since the universe seems doomed to die in one way or another, perpetuating the human race and improving the lives of its members is also pointless, which would be a seriously pessimistic outlook on life.
If life is finite, there’s no reason to make it shorter than it has to be, and, moreover, there’s no reason to make it less pleasant than it could be. If rejuvenation biotechnologies reached their full potential, we could be able to always enjoy youthful health no matter our age for as long as we live, however long that may be. Regardless of this length, there is no reason why the final years of our lives should be spent in the company of disease and decrepitude.
If, one day, the Big Crunch or something else comes to put an end to our lives, so be it. Death of the universe preceded by good health sounds like a better deal than the death of the universe preceded by cataracts, for example. At least we’ll be able to see what’s going on!