Here's a Russian press interview with biomedical gerontologist and radical life extension advocate Aubrey de Grey - which you might want to read through the Bable Fish translator.

UPDATE 02/28/2009: The Google translation is much better, so read that one instead.

[Interviewer] But - but as it is possible to interfere without the [full] understanding [of processes of aging]?

[Aubrey de Grey] We indeed interfere, without having precise knowledge about why cancerous tumor arose. Medicine generally frequently accomplishes the effective actions, not based on the precise knowledge. To take, for example, atherosclerosis, this "killer number is one" in the developed countries. We approximately visualize, as it is developed also it leads to what. But to mechanically destroy the cloth of atherosclerotic platelet we quietly can also without the knowledge about how this platelet it grows.

...

[Interviewer] But there are hundreds of fundamental scientists, connected with the problem experimentally. For example, they study the so-called "genes of aging", but in this case they do not want to speak about the possibility to stop process itself. Why?

[Aubrey de Grey] The experiments of many scientists can prolong the life of cell, simplest organism, but I do not think that this will work at the level of man. However, the majority of researchers keep silent not therefore, but because they fear to lose financing. They depend on those average men themselves, who do not want to be charged by superfluous optimism, and therefore they are careful.

The quality isn't great (it can translate "nematode" just fine, but produces artifacts like "it is still more important, here to eat the biologists") but you'll get the gist. The points quoted above are two of the most important considerations for advocacy:

• Firstly, that we can make significant progress in developing solutions to a problem in advance of complete understanding. I see the present debate over the level of effort to devote to development based on today's knowledge to be the most important determinant of our future life spans. Will the research community get to work, or will it put off developing therapies for another few decades?
• Secondly that a strange self-perpetuating culture of conservatism and denigration about engineered longevity came into being in past decades, and must be shattered if we are to make progress.