Superlongevity: Is it Inevitable and is it Good?

Mark Walker

Comments welcome:

Forthcoming coming in Death And Anti-Death, Volume 3: Fifty Years After Einstein, One Hundred Fifty Years After Kierkegaard, edited by Charles Tandy. To be published by Ria University Press 2006, Palo Alto, California.

CHAPTER XYZ

Universal Superlongevity:

Is it Inevitable and is it Good?

Dr. Mark Walker

Department of Philosophy McMaster University

Trinity College, University of Toronto

1. Population Predictions

Rapid advances in the understanding of human aging and possible ways to combat it, e.g., discoveries in genetics (Kenyon, 1996), stem cell research (Shostak, 2002), the cessation of aging at the cellular level (de Grey, 2005), and nanomedicine (Freitas, 1999), point toward the possibility that sometime this century we will have to confront the decision of whether we should radically extend the healthy lifespan of humans. Just imagine being 1000 years old with the body of a twenty-five year old (or so) to get some idea of the potential promise of developments in biotechnology. Given that such an extended lifespan (‘superlongevity’) is technically possible, I propose to examine two related questions: To what extent will our descendents opt to use this technology? And if they do so, is this a good thing, morally speaking? I argue that we should predict (almost) universal adoption of superlongevity; and, that this is a morally good outcome.

Given the enormous contemporary interest in looking young among certain segments of our society, it may seem reasonable to think that everyone will line up to access this technology. But perhaps this judgment is skewed precisely by the contemporary hype over looking young e.g., make-overs, botox injections and cosmetic surgery.1 Why not think that this is a fad, and that it is more reasonable to suppose, as with so many other choices in life, that some will say “yea” and some will say “nay”? Alternatively, perhaps it might be thought that the nearly universal adoption of technology (at least in the wealthier nations) ought to be a good indication of how many will choose to use superlongevity technology. The qualification of “nearly universal” is necessary since there are of course exceptions: the Amish are one conspicuous example of the rejection of much modern technology. But this comparison may be misleading. Not all technologies are widely adopted, and ‘superlongevity technologies’ refers to specific technologies designed for specific purposes. It is true that certain technologies, such as the telephone, television, and radio, are used by over 90% of the population in the rich nations; yet, most people who live in first world nations could afford a jetski, but its use is confined to a small fraction of the population. Will superlongevity technology be the jetski of the future? Furthermore, there is at least one crucial difference here that ought to give us pause. The type of technology under consideration involves altering human biology in a manner that many might consider “unnatural”. The idea of humans living for hundreds or thousands of years is unprecedented in our history. Conceivably, many will reject this as fundamentally different from other types of technologies, and so find no contradiction in using dishwashers and cell phones, etc., while forgoing the use of radical life extension technology. Perhaps some will do so for religious reasons, others might reject it for reasons similar to the opposition to genetically modified foods, that is, that we ought not to alter the biology of any species including Homo sapiens.

It may be thought that systematic empirical research should put us on a firmer footing here, since drawing analogies from our current practices does not seem to provide a univocal answer. Such research might survey people today to find out whether they would adopt superlongevity technology if it were available, and use this as an indicator about how future populations might decide the issue. However, I do not know of any such studies.2 Furthermore, we run into the problem of surveys asking people whether they are likely to adopt some emerging technology are notoriously unreliable. For example, asking about microwave ovens in 1970 would have indicated that there would be little future interest or demand for this device. Obviously, then, such research would be a bad predictor of the fact that microwave ovens are overwhelming embraced today in the rich nations.

To add further difficulty here is the (seeming) problem that long-term predictions might be confounded by small changes in individual preferences. This point is nicely illustrated by a report “World Population to 2300” (2002) released recently by the population division of the UN’s Department of Social and Economic Affairs. The report predicts 8.97 billion humans on earth in the year 2300. However, the report is quite clear how sensitive this forecast is due to a number of factors including fertility rates. The authors note, for example, that fertility rates at .3 children above replacement would lead to a quadrupling of the prediction to 35 billion in 2300; and with fertility rates at .2 children below replacement leads to a prediction of just over 2 billion inhabitants in 2300 (a significant decline from our present population of over 6 billion (pg1)). So, small changes in individual preference for the number of offspring to have, therefore, can make a huge difference in the long-term.

So, it may seem at best incautious and at worse pointless to speculate how the future population of the world will divide between those that seek superlongevity and those who choose a natural life span—we will refer to them as ‘mortals’—given we do not know what people’s preferences will be in the future. However, I want to argue that, if given the choice, those adopting superlongevity technology will eventually make up (almost) the entire population. This conclusion holds even if there is a fairly small preference rate3 among future individuals for superlongevity to the mortal life.

2. A Simple Model

Admittedly, the claim that superlongevitists will eventually compose almost the entire population may seem counter-intuitive. For example, if the rate that individuals opt for radical life extension is 50% then shouldn’t we predict that 50% of the population will choose a “mortal life” and 50% that of a superlongevitists’, and if the preference rate is merely 10% then they will comprise 10% of the population, and so on? The answer is that this is certainly what we should expect during the first generation of mortals. However, since superlongevitists do not die, their numbers will continue to accumulate and so they will tend to become an increasingly large segment of the population.

To see this in more detail let us think about a simple model based on the following assumptions.

1.  Availability: Superlongevity technology is available to all by 2050.

2.  Population Stability: The world’s population is stable at 10 billion from 2050 for the foreseeable future.

3.  Preference Rate: For every individual, there is some non-negligible probability that he or she will choose to adopt superlongevity technology.

4.  No Defection: There is no defection among the superlongevitists (none of them die).

It may be helpful to work through an application of these assumptions before discussing their plausibility. For our first application, let us assume a constant 50% preference rate for the adoption of superlongevity technology, as Fig. 1 illustrates. That is, we assume that every individual has a chance to decide for him or herself whether to adopt superlongevity technology, and half opt for it, and the other half choose to live a mortal life.

Figure 1

The mortal population we will assume experiences a complete turnover in its number every 70 years. Given the 50% preference rate, five billion of those alive in 2050 adopt superlongevity technology and five billion choose the mortal life. So by the year 2120 the original 5 billion mortals will be replaced. Since we are assuming that the population is stabilized at 10 billion, this means that by 2120, 5 billion new persons are born. Since the preference rate is constant at 50%, 2.5 billion of the 5 billion born between 2050 and 2120 choose superlongevity technology. So in the year 2120 there are 7.5 billion superlongevitists and 2.5 billion mortals. From 2120 to 2190, 2.5 billion mortals die. Their replacements again choose the mortal life at a 50% rate, so by 2190 the mortal population has been reduced to 1.25 and the superlongevitists’ population has swelled to 8.75 billion. As Fig. 1 indicates, looking 330 years into the future (only slightly longer than the scope of the UN population study) the mortal population is but a small fraction of the total population (about 3%).

Figure 2

This result is not simply an artifact of the 50% rate; since even with a relatively low 10% preference rate, inextricably superlongevitists become a larger and larger proportion of the population. As Fig. 2 indicates, within just over 300 years they comprise over 40% of the population.

Fig. 3 shows the 10% preference rate for the next millennium. The population of mortals has slipped to 25% of the total population within one thousand years.

Figure 3

So, we end up with the somewhat strange position where, even though there is an overwhelming preference among individuals born in the next thousand years for the mortal life (90%); the superlongevitists constitute the majority of the population within 500 years, and within a millennium make up about three quarters of the population.

3. Assumptions

Let us now turn to the assumptions of the model, asking how crucial and plausible they are.

3.1 Availability.

Our model assumes that superlongevity technology will be available in 2050. The start date here is not particularly important for the logic of the argument; for if superlongevity technology does not become available until 2100, or it is available as early as 2025, this does not affect the conclusion that eventually, mortals will tend to disappear from the population. However, the question of availability seems inextricably linked with the question of affordability. Notice that our initial model makes no distinction between preference and realized-preference: basically the difference between what people want and what people can get. If superlongevity technology is extremely expensive then there may be a large gap between the desire for the technology and the means to obtain it, that is, between preference and realized-preference. The applications of the model above are clearly based on realized-preference. For example, imagine the technology becomes available in 2050, and 50% of the world’s population would use it if they could, but only 20% of those who desire it can afford it. Here, realized-preference would be 10% of the world’s population.

Are there good reasons to suppose that there will be a large gap between preference and realized-preference? The UN model predicts that poverty will still be a major social issue in 2050, which suggests that there may be some gap between preference and realized-preference here. How large this gap is will depend on (among other things) how much of the world remains impoverished when superlongevity technology is developed, and the cost of superlongevity technology. Admittedly, we do not know the answers to these questions, but it is worth commenting on a line of thought that suggests that superlongevity technology will inevitably be expensive. This line of argument, which I have encountered in conversation a number of times, basically runs as follows: “Look how expensive medical treatments are presently, and they really don’t do a whole lot in terms of extending our lives. Superlongevity technology will have to do so much more, so it is likely to be very expensive.” In my experience this line of thought is so prevalent that I propose that we dub this the “iron lung fallacy”. To see why, imagine someone in 1940 reasoning thus: “Look how expensive it is to treat polio victims. Polio victims eat up an enormous share of our health budget, the cost of running an iron lung4 to keep a single patient alive is staggering. To actually cure polio once and for all is to ask so much more of technology, so we should expect that a cure for polio will be prohibitively expensive for the foreseeable future.” Of course, we know that it costs a few cents per polio vaccination, and that it is much cheaper to treat everyone for the cause of polio in this way than attempting to help patients deal with their symptoms over a lifetime. Similarly, it may be the case that it is much cheaper to treat the causes of aging than it is to treat the symptoms of aging. As I said, we don’t know at this point how much superlongevity will cost, but it is wrong to assume that it will necessarily be expensive. It may turn out to be much cheaper per year to keep a superlongevitist alive than to treat mortals today, precisely because at present we must contend with all the problems associated with deterioration. Moreover, looking simply at health costs is to overlook the fact that one of the costs of choosing a traditional mortal life is that enormous financial resources must be reinvested in the young. So, the cost of any superlongevity treatments would have to be weighed in part against the expense of raising and educating children to replace the dying adult population.5

3.2 Stable Population

As mentioned earlier, the UN study estimates that the world’s population will climb to about 9 billion in the next fifty years or so, and then will hover around there at least until the year 2300 (the end of the projection period). For ease of illustration, our model assumed a population of 10 billion. Obviously, the size of the initial population does not affect the general line of argument. If the world’s population is 10 million or 10 trillion, and there is a 50% preference rate, the same decline (as a percentage) of the mortal population would occur as illustrated in Fig. 1, thus, whatever the initial population, mortals will constitute only about 3% of the population within 300 years.