Wednesday, May 25, 2011

Who Wants to Live Forever? Agar on Negligible Senescence (Part Two)

He'd like to live forever, would you?

(Part One)

This post is the second in a brief series looking at Nicholas Agar’s critical assessment of the pursuit of strategies for negligible senescence (SENS). This is an idea associated with the gerontologist Aubrey de Grey. The pursuit of SENS, if successful, could allow us to live indefinitely extended lives with all the vim and vigour of young adults. Accepting that such a programme is feasible, the key critical question is whether we should pursue it.

In part one, I sketched a basic pro-SENS argument. I also sketched Agar’s three main lines of attack on that argument. In this post, I will go through all three in more detail. One general note at the outset: most of Agar’s comments depend on speculative predictions about the likely outcomes of negligible sensescent. As a fan of science fiction, I enjoy this, but it might prove to be frustratingly suppositional for some.

1. An (un)healthy dose of Fear
Agar argues, contra de Grey, that the success of SENS will not allow us to live lives that are roughly comparable to those lived by contemporary young adults. The reason being that a massively extended lifespan will dramatically alter one’s attitude towards certain kinds of risky activities. In short, it will turn you into a simpering, cowering wreck, paralysed by pathetic anxieties and reluctant to set foot outside your own door for fear of some fatal accident befalling you. The logic behind Agar’s sentiments is easily expressed.

Consider a simple decision that might face you today: the decision of whether or not to drive to the cinema to meet your friends and watch a movie. There are risks and rewards that need to be assessed when making this decision. There is the small, but nonzero, risk of a fatal road accident, and there is the moderate, but not negligible, reward of enjoying a congenial evening with your friends. For most of us today, unless we have other more pressing commitments, the rewards of going to the cinema will probably outweigh the risks.

But things will be oh so different for the negligibly senescent. They will have so much more to lose from the trip to the cinema. A forty-year-old senescing human being can expect to have maybe ten or twenty years of good health left (followed by more years of deteriorating health); a forty-year-old negligibly senescent being will expect to have maybe 1000 years of good health left. The increased life expectancy means the negligibly senescent have more to lose and so will have increased costs associated with a simple decision like driving to the cinema. [I’d like to see a calculation here, but Agar doesn’t offer one]

De Grey himself confirms the idea that the negligibly senescent will be more risk averse. He comments in one interview (p. 115 of Agar) that he reckons once we achieve negligible senescence driving will be outlawed because it is too dangerous. He resiles from this somewhat in a later interview when he suggests that cars will simply become more heavily protected. Whatever form it takes, increased risk aversion does seem to be likely consequence of increased life expectancy, as is evinced by contemporary attitudes to health and safety compared to those of former generations.

Increased risk aversion will have significant impacts on the kinds of lives the negligibly senescent will live. An increased reluctance to drive is only the start. Driving, after all, is a relatively safe activity. What about foreign travel to the more distressed regions of the globe or high-impact sports? Both could be ruled out, along with many more enjoyable activities such as real (as opposed to virtual) sexual intercourse. And this is where we hit upon the crucial point: becoming more risk averse might result in us losing much of what we value. Here we get a whisper of Agar’s species-relativist argument -- a whisper that will wait until chapter 9 to be properly heard.

There is a flipside to negligible senescence and risk that must also be addressed. While it is probably true to say that the negligibly senescent will avoid exposing themselves to sources of sudden or accidental risk, the same does not hold true for their exposure to sources of gradual or accumulating risk.

Currently, activities such as smoking and the excessive consumption of fast food are risky, but only in the sense that their continuation gradually increases the risk of contracting disease or illness. The advances medical treatment that accompany negligible senescence can be expected to reverse the risk associated with these activities. As a result, although we may become more isolated, timid, stay-at-home beings, we can at least smoke and eat to fill the emotional void in our lives.

[Cork band Fred sing about the need for a healthy dose of fear...]

2. Hidden Costs
Agar’s second line of attack on the pursuit of SENS is to point out that there may be hidden costs associated with extended life. These costs might be such as to reduce life expectancy from that envisioned by de Grey.

The main hidden cost is likely to come from an increased susceptibility to bacterial and viral infection. Bacteria and viruses reproduce and evolve at a frightening rate. As they do so, they tend to adapt to meet the challenges posed by their environments. This is readily apparent in the growth of antibiotic-resistant bacteria. At the moment, outside of antibiotics, sex and death are among our primary defences against such pathogens.

Bacteria and viruses attack the body by attaching themselves to protein receptors on our cell surfaces. Sometimes they are unable to do this because they have not adapted to latch onto the relevant protein receptors. But given enough time, they are likely to do so (indeed, de Grey makes use of the adaptability of bacteria in part of his scientific defence of SENS). This is where sex and death enter the picture. Death ensures that particular types of cell surfaces don’t hang around for too long; and sex allows for novel combinations of genetic material to create new receptors.

But since the negligibly senescent won’t be dying as early, and will probably not reproduce (to prevent overpopulation), they may become highly susceptible to infectious disease. Defenders of SENS can, of course, interject here that medical advances may be able to counter the effect of these highly adaptive bacteria and viruses. This is indeed possible, but that’s not the issue. The issue is whether it is likely. Bacteria evolve quickly, are we confident that medical advances will outpace them? This is something we need to consider when determining the desirability of pursuing SENS.

3. Social Costs
Agar’s final line of attack looks to the possible social costs of pursuing SENS. We’ve already commented on the effects of negligible senescence on the individual and their attitude to risk. How might those individual effects translate into social effects?

On the one hand, there might be some laudable social effects. Due to their increased risk-aversion, the negligibly senescent are likely to avoid the hollow pursuit of glory on the battlefield. Violent conflicts and wars may become a thing of the past as we all retreat to our hermitages to indulge our predilections for fast food, cigars and virtual sex.

We must, however, be careful when considering such positive effects. If different societies achieve negligible senescence at different times, then those who have achieved it may become more vulnerable to attack from those who have not (and are still hungry for glory on the battlefield). This concern is not strictly speculative. As far as I recall, some believe the increased risk aversion of Western societies is what renders them vulnerable to, for example, Islamic fundamentalist terrorism. The concern could be overcome by making negligible senescence available to all at the same time, but Agar thinks this will be highly unlikely: the wealthy funders of SENS are unlikely to wish to hold-off on receiving its benefits until they become universally available. Robot armies might also be an option, but Agar has already expressed qualms about making artificial intelligence too intelligent.

There is a deeper problem here. Increased risk aversion may end up compromising the very foundations of the SENS programme. If we are to achieve de Grey’s goal of longevity escape velocity (LEV) then we need to launch an aggressive campaign of developing and testing medical interventions. But testing such interventions is a risky business. Who among the risk averse is likely to subject themselves to unproven techniques?

Agar marches off into highly speculative territory in responding to this. He reckons the War on Aging (de Grey’s term, not Agar’s) will lead to an increased disregard for the welfare and rights of those subjected to medical tests. He suggests that the use of those who do not have access to longevity increasing treatments could be used as guinea pigs, and that the introduction of a kind of medical conscription is not impossible.

Anyone interested in pursuing these kinds of scenarios further would be well-advised to read Kazuo Ishiguro’s novel Never let me Go (or check out the film of the same name). It depicts a society that breeds an underclass of donors whose organs are harvested in order to help others live for longer. It’s beautifully written and highly evocative


  1. I don't buy the risk aversion argument. It makes sense from a purely rational perspective, but humans are far from purely rational. Generally speaking, people actively avoid thinking about their own mortality, which serves to increase our risky behaviour. Not to mention that to a young adult, death seems like a distant concern, whereas to an 80-year-old, it's an impending threat. Extend the 80-year-old's life by 200 years, and I would imagine they would become more like the young adult.

    People don't calculate risk in a rational manner, which is why more are afraid of plane crashes than car crashes, despite the risk of the latter being much higher than the former. All this suggests to me that the risk aversion argument is weak and unsuccessful.

  2. Agar does talk about the different attitudes toward risk at different stages of life in his book. I left that part out just to cut things down. After pointing out something similar to what you just pointed out, he opines that those who follow de Grey's enhancement programme are likely to be more rational than the typical 20-year-old because they are self-consciously directing their lives toward the reduction of risk. (On page 116 if you're ever in the vicinity of a copy).

    I'm not sure about that argument. On it's own I might be willing to tolerate it, but it's indicative of something that has really annoyed me about the book, namely: it displays an inconsistent attitude toward the normative role of psychological biases and rational choice theory.

    In the passage just mentioned (i.e. that on p. 116) he seems to dismiss known psychological biases in favour of a more idealised normative theory of rationality (he also does this in the chapter on Nick Bostrom). But in other passages he uses facts biases as a basis for his normative claims (ironically, he does that in the chapter on Bostrom too).