This is one of my five FAQ ("Frequently-Asked Questions") pages: it covers general arguments that SENS won't work. [Specific arguments, i.e. ones concerning the actual scientific proposals that make up the SENS approach, are dealt with on the "SENS targets" pages and in greater depth in my publications; the best place to start is here.] The other FAQ pages respond to:

- concerns that defeating aging is a bad idea or a low priority,
- questions about how long people of what current age may live,
- criticisms of how I'm going about making SENS a reality, and
- queries about how one can help the SENS effort.

1000-year lifespans! - that's obviously ridiculous
We're far too ignorant about aging to have any idea how to combat it
If you had lab training, you'd know how infeasible your suggestions are
Why even think about reversing aging until we can greatly retard it?
Where's your data?
Don't you know what Crick said? "Evolution is cleverer than you are"
People have always wanted to cure aging, but we only ever make slow progress
Aging isn't a disease, so obviously it can't be "cured"
Why don't your senior colleagues echo your optimism about timescales?

1000-year lifespans! - that's obviously ridiculous

It's certainly ridiculous to suppose that we will have therapies in the next few decades that will allow us to live more than a few decades longer than we do now, let alone 1000 years. But we don't need therapies like that in order for people who are in middle age in a few decades from now to live to 1000. Why not? Because we only have to fix things in time, not all at once. We don't need to know how to stop people dying of aging at age 150 yet -- we won't need to know that until we have some 150-year-olds. Same for 200-year-olds, and so on. When we look at the historical precedent for the rate at which new technologies (flight, computers, etc.) are improved once they are first achieved at all, this means that even the first-generation rejuvenation therapies, the ones that give us only a few decades, will almost certainly be enough to put us above "life extension escape velocity" such that we won't die of aging however long we live. For more details of why, see my timeframes page.

We're far too ignorant about aging to have any chance of combating it

No short answer to this could be persuasive; my answer is strong by virtue of its attention to detail. To learn why I claim that we are likely to cure aging within 30 or so years if we start trying, see my detailed science pages, starting with this one.

If you had lab training, you'd know how infeasible your suggestions are

It's been extremely heartening to me in my gerontology career how rarely this argument has been used against me, even out of my hearing. This shows that my colleagues are genuine scientists more interested in ideas than in who generated those ideas. But also, this criticism is not entirely ad hominem anyway: I do indeed have a less detailed idea of how hard some techniques might be to develop than people who have laboratory experience of doing similar things. That's why I always discuss my proposals in minute detail with the experimentalists whose work is most closely related to my ideas. Sometimes I do this in informal ways over a beer, and sometimes I run actual meetings to scrutinise the details really thoroughly. Two good examples are the meetings documented here and here, both of which led to publications co-authored by all or most of the participants.

Most biogerontologists doubt my predicted timeframes for progress in postponing aging (at least in what they say and don't say publicly). Unfortunately, the main reasons they do are not very good. One is that biologists have little training in developing piecemeal manipulations of complex systems and thus focus on seeking "holistic" ones (magic bullets), which are probably absent in the case of aging. The other is that some of my proposed methods involve areas of biology that are distant from what most gerontology conferences (my own excepted!) cover, so most gerontologists (who are rightly skeptical of what I say initially, and who lack enough time to read the experimental work that I cite in my papers and thereby satisfy themselves that I may have a point) don't know the relevant facts.

This situation is not so bad as it might be, because most gerontologists realise that they know a lot less about my proposed technologies than they might, and they therefore refrain from ridiculing me -- and indeed offer me considerable, albeit often only tacit, support. A few of my colleagues, however, do reason that because they know more than I about how to work a pipette (since I lack experimental training) they therefore know more than I about how difficult things are that have not yet been done, even though I have researched the relevant literature and discussed the topics extensively with the relevant scientists and they have not. Luckily, most of those colleagues also "play fair" -- they say what they think of my chances of success, but at least they say it openly, in print. The only colleagues I resent are the very few who ridicule me anonymously but refuse to engage me in proper debate. (I name no names -- not here, anyway; you know who you are.)

Why even think about reversing aging until we can greatly retard it?

Because it's not the case that reversing aging is necessarily all that much harder (or indeed any harder) than retarding it. Retarding aging is like keeping a leaking boat afloat by putting your hand over the hole. Reversing aging is like keeping it afloat by throwing water over the side. Of course, if you don't throw water out quickly enough then the boat will still fill up, but if you do, you can make a nearly-sunk boat almost empty again, which you can't ever do by putting your hand over the hole. But both methods require about the same technological sophistication.

Where's your data?

I am always rather depressed when I see people rejecting my predictions on the basis that I have no data -- as if the Wright brothers had data in, say, 1900 suggesting that powered flight would be developed a few years later. Of course they did have data in the sense that any engineer bases his designs on existing knowledge about the system he wants to manipulate -- and so do I, as will be apparent to those who take the trouble to read the science pages on this website (start here), let alone my publications. The sort of data whose absence people who ask this question seem to find relevant is modest life extension from existing technology, much as if the fact that neither engines nor wings can fly constitutes evidence that the combination won't fly either.

Don't you know what Crick said? "Evolution is cleverer than you are"

Crick's entirely correct statement is irrelevant to curing aging -- but this irrelevance illustrates the main distinction that I think I can make between how I think about fixing aging and the way that most of my colleagues think about it. Most of my colleagues don't really think about postponing aging as medicine at all, and therefore they don't think about it as a type of engineering. They think about it as a sort of attempt to copy evolution. Evolution doesn't do medicine, it does new types of organisms. And evolution is, indeed, pretty good at creating long-lived organisms starting from relatively short-lived organisms (when it is so inclined -- which it isn't always, but it is often enough). But not only does it take a long time to do it, it also has very different tools from what we have, so it can't really do what we would call engineering. It hasn't got the right sort of ways to manipulate DNA in the test tube, for example. It's only when one starts to think about how one could approach these questions in a medical way that one starts to be able to see the sorts of avenues that are available to us but aren't available to evolution, and of course it's only when one starts identifying these possible avenues that one can actually evaluate their feasibility and thereby get some sort of estimate of the time-frame in which we might be able to implement them. A dumb person can crack a nut a lot faster than a smart person if the dumb person has a nutcracker and the smart one only has a toothpick.

People have always wanted to cure aging, but we only ever make slow progress

I've recently written a paper entitled "Extrapolaholics Anonymous" detailing my response to this, which will appear in preprint form on my publications page when it comes out. In brief: one cannot reliably predict the rate of technological progress by extrapolation. In 1900, extrapolation of trends in the speed of ocean-going liners over the previous century or two would have predicted that the time taken to travel from London to Washington D.C. in 2004 would be at least a couple of weeks. I happen to be writing this paragraph while in transit on just such a trip, which began three hours ago and will end in four hours. Extrapolation anticipates the rate of technological progress on some occasions, but when it fails to do so it can fail spectacularly. One can more reliably predict the extent of progress in the next 10-20 years (though not more) by examining the tools that are available with which to construct that new technology and how those tools might be so used, which is what I do.

Aging isn't a disease, so obviously it can't be "cured"

Call it what you like. Aging is a biological phenomenon that causes debilitation and death. These things are undesirable. Thus, it seems pretty reasonable to me that something which stops getting older from causing debilitation and death can be called a cure for aging.

There is a specific sense of the word "cure" for which aging indeed cannot be cured, though, so let me define just what I mean by "cure." What I mean is, to have as much control over it as we have over things like tuberculosis -- diseases that we pretty much know how to stop people dying of -- but not necessarily to do it once and for all. So I definitely mean not simply stopping its progression, but reversing its progression -- taking someone from a state of advanced suffering from the thing, whether it's something like tuberculosis, or whether it's aging, to a state where they are not suffering from the thing. But consider a disease like herpes, or malaria, or AIDS. At this point the prevailing therapies for these diseases do not actually eliminate the disease-causing agent from the body, they only make it latent so that symptoms are prevented. (With AIDS we can barely do even that so far, of course, but you get the idea.) With such diseases, one can have a recurrence of the symptoms without actual re-infection -- just by stopping taking the treatment. So it is with aging: treatment will have to be periodic, for however long one lives.

Why don't your senior colleagues echo your optimism about timescales?

I sometimes call this one "The curious case of the catatonic biogerontologists"...

The SENS strategy as described here purports to have all the characteristics that should make it persuasive: it's detailed, it's thorough and it's all firmly based on established experimental work in the various relevant areas of biology. So, you may well ask, where's the catch? Why, on all the many documentaries on aging that remain so popular, don't my colleagues come out and advocate the work that I advocate?

There are three main reasons why most mainstream gerontologists remain so conspicuously absent from the growing band of vocal advocates of the SENS approach to curing aging. They are all understandable, but given the importance of the problem and the key role that senior specialists play in determining public opinion and hence public policy, I feel that none of them is a legitimate excuse.

The central reason is simple ignorance of the relevant science. Biology -- even human biology -- is a very big subject, so nobody can hope to understand it all in depth. Thus, biologists restrict themselves to understanding in depth a rather narrow subset of biology and they trust each other to focus on the other areas. Unfortunately, this strategy relies utterly on having a good instinct for when an area not hitherto perceived as relevant to one's own area has become so as a result of a new piece of work. Most of the areas that I have introduced into the biology of aging have so far received only limited attention because most biogerontologists don't instinctively see how they could be useful.

The second reason is really subsidiary to the first, in that its importance is in sustaining the ignorance I just referred to. The progress of ideas always has enormous inertia, on account of the emotional, intellectual and financial investment that those who hold conventional views have made in those views. Scientists, like others, find it difficult to write off that investment and embrace a new paradigm even when the argument for that new paradigm is very comprehensive. This manifests as a reluctance to consult relevant scientific literature, for example, or even to entertain the idea that such literature is relevant in the first place. It also manifests as a preference for avoiding overt debate on such matters, since any such debate opens up the risk of being forced to acknowledge the superiority of the new paradigm. None of this is conscious, but it is an indescribably powerful force against progress. In this case, the idea that reversing aging might be easier than slowing it down a bit is so counter-intuitive that many of my colleagues are inclined to dismiss it out of hand before taking the time to look at my argument in detail.

The third reason my colleagues mostly don't say what I say is political. Scientists prefer to promote and discuss what they're working on. They aren't so keen to tell people that they would be working on something altogether more interesting or ambitious if only their funders had the imagination and courage to fund it, because that's a quick way to lose funding even for unambitious work. Now, you might ask, why are funders so unambitious? In industry it's because of short-termism, of course: firms that can make money quickly and certainly with boring products will do so in preference to making money far in the future and with much less certainty with ambitious products, even if the amount of money on offer in the latter case is far bigger. In the public sector, the main reason is that funders don't want to be thought to be wasting tax-payers' money on blue-sky work with no chance of success. So, the ultimate problem is the pessimism of voters. But, of course, that pessimism is due precisely to what senior biogerontologists say and don't say on the television... This "triangular log-jam" (see below) is the fundamental problem with getting more money into life extension research. The strange arrows with flat heads are a notation used in genetics; they mean "inhibits".



It can be unblocked at any corner, of course. My work is focused on the "biogerontologists" corner because I know them all personally and because they are few in number. The quickest way to change the minds of scientists regarding research priorities, however, is to remember that scientists will do anything interesting for food. Hence, an alternative supply of funds is a solution:



Finally, both the scientists and the prospective philanthropists may be encouraged to take the plunge if a bit of publicity comes their way:



and this is one motivation for the Methuselah Mouse Prize.