Despite the fact that the principal, fundamental biochemical differences distinguishing old tissue from young tissue are a largely settled and defensible consensus these past twenty years [1], there are many theories of aging [2]. From the point of view of development of treatments for aging, the most important divide is between programmed aging theories (a loud minority) and the view of aging as accumulated damage (the majority). A simplistic way of looking at it is to say that in the programmed aging view epigenetic change causes damage, while in the aging as damage view the damage is a side-effect of the normal operation of metabolism and leads to epigenetic changes as a reaction.

(This simplistic view obscures a lot of argument within programmed aging, just as there is a lot of argument within the aging as damage view. The author of this article has developed a novel evolutionary theory of programmed aging to compare and contrast with a range of others, such as the hyperfunction theory of aging).

At the present time we are entering an age of genetics. Whether the research community thinks of aging as a program or not is very important from the point of view of which treatments they try to chase. If aging is programmed, we'd expect damage repair to be of limited utility. If aging is accumulated damage, we'd expect attempts to change epigenetic patterns and gene expression levels to be of limited utility.

Strangely, despite the fact that most researchers think of aging as damage accumulation, the research community actually spends much more time on trying to catalog and alter epigenetic and gene expression changes - the path that clearly won't have any great impact on the underlying causes of aging in that model. So if you do support programmed aging you should be pretty happy with the way things are going. If you don't, you really shouldn't: the field is heading in the wrong direction, for bad reasons. i.e. that it is easier to raise funds for the study and alteration of epigenetics, or the Big Pharma style development of drugs to do the same, which is the very hard exploration of how to safely alter a massively complex system that is very poorly understood, while it is much harder to raise funds to aim at rejuvenation through repair of damage, as this latter is a comparatively new approach in medicine.

So despite the fact that the majority of the field thinks that aging is damage, next to no groups work on damage repair. They are largely working on building a catalog of the precise way in which damage interacts with metabolism in great detail, a part of the ongoing process of producing a complete map of metabolism, a process that has only just started in the grand scheme of things: what we have today is just the sketch of an outline.

But that list of forms of damage that cause aging? That's good and defensible and therapies could be built starting now, with a proposed ten year timeline to get to working prototypes in mice given $100m/yr funding. The whole and main point of the SENS strategies for aging is that we can skip over the need for full understanding of the detailed operation of metabolism and just fix the damage we know distinguishes old tissue from young tissue. This is the logical way to go if aging is thought to be damage. And yet it has taken a decade of advocacy to get even a small number of researchers in the field to support this approach. [3]

Want to prove whether aging is programmed or not? Implement SENS therapies, a clear and very detailed research program with a billion dollar price tag (much less than has already been spent on investigating sirtuins and mTOR, efforts that have produced nothing but knowledge of metabolism, and none of the promised treatments to modestly slow aging in healthy individuals). If that produces actual rejuvenation in mice, then aging is damage accumulation. If it doesn't, then it is programmed. End of story, fastest way to the target, job done.

[1]: http://sens.org/research/introduction-to-sens-research

[2]: http://www.senescence.info/aging_theories.html

[3]: http://sens.org/about/leadership/research-advisory-board