Life extension and natalism

In population ethics and the ethics of aging, the life extension and natalism tension is the problem of whether it is more important to bring more people into this world, or to keep older people alive. This is important to consider because if (say) older people are not more valuable than younger people or people who don’t yet exist, then life extension may not be as important as a cause. Some considerations:

  • Older people may have a lower quality of life compared to people who are yet to be born (and in general younger people) due to disease from old age.
  • It may take less resources to keep older people alive than to raise new people to adulthood, but it may take less resources to simply bring new people into the world than to keep older people alive for a certain amount of time. (This is an empirical question that can be settled. Though the required resources for raising people, keeping people alive, etc., will change in the future.)
  • Older people may be more valuable because of their historical/cultural knowledge (i.e. they are, in a sense, “walking history books”). On the other hand, new people add new viewpoints, may be more valuable because everything they experience will be new1.
  • Even if ultimately newer people are more valuable, there is the problem of the possible “inevitability” of anti-aging interventions. In other words, it’s probably difficult to fully stop research on anti-aging (and possibly unethical to do so), so anti-aging interventions might become available even when we realize that newer people are more valuable. As a result, people can try to apply these interventions (since non-existent people have no say in anything) to themselves to live longer. Thus this question might only be an intellectual interest, since we can’t do anything about it. (Though there might be some clever ways to deal with this, e.g. by using a “natalist tax” on anti-aging interventions.)

Status quo

It seems rare to find people who find the creation of life to be an obligation. This is for instance Aubrey de Grey’s response to the concern that we are denying new lives by extending existing lives.2

Economist Bryan Caplan notes the lack of pro-life (regarding abortion) utilitarians,3 which is evidence that people do not see the creation of life as an obligation.


Here is Gerald Gruman, quoted by Callahan4 (pg 27):

A life span that is truly modern in attaining humanist, meliorist, and individualist values still is ahead. At present, the worth of the individual is not so much a fact as a goal. This interpretation requires confronting the truism in contemporary culture that resources should be invested preferentially in the young, because they have a future and the elderly do not. However in the furthering of a genuinely modern culture, it is the aging who actually have pride of place; they are where the action is, for they are something new as a large population sector. The solving of their problems is a make-or-break task for the modern forces that brought them in[t]o being. Moreover, the elderly, as individuals, face challenges new to themselves which call for successive, creative renewals of identity. And as part of humanity, they live in a historically early, or new phrase of accelerated modernization. Thus, the aging population does have a future, as it becomes re-engaged at the frontier of modern cultural adaptation and realization through historical time.

(I’m not sure the quote makes very much sense; I may have to go to the original to understand the full context.)

Callahan himself (pg 42):

The elderly are in the best position to keep alive the past, to integrate the history of which they are a living link with that present which they share with younger generations. This could be as valuable in our society as it was in preliterate societies. The integration what was and what is, and how they cohere with each other, is something that only the elderly can provide within the confines of family and local community life. Only they are in a position to have experienced some patterns and cycles; […]

See also this comment by Lila Rieber:

Another way of understanding life-extension stuff is that it increases the number of people on earth at a given time, all else being equal. But the more obvious way to increase the number of people on earth is to promote births. Of course, there are transition costs to death: people really don’t like dying. On the other hand, there may be diminishing returns to life, and people might prefer to improve their chances of being born, whatever that means. I am floating in the ether and am offered a tradeoff: I can increase my probability of existing, but this will decrease the length of my existence if I receive an existence. I’m not sure what probability-length tradeoff I’d choose as optimal.

Eliezer Yudkowsky:

For now, one of the reasons I care about people alive today is the thought that if creating new people just divides up a finite pool of resource available here, but we live in a Big World where there are plenty of people elsewhere with their own resources… then we might not want to create so many new people here.  Six billion now, six trillion at the end of time?  Though this is more an idiom of linear growth than exponential—with exponential growth, a factor of 10 fewer people just buys you another 350 years of lifespan per person, or whatever.

Yudkowsky in “For The People Who Are Still Alive”:

Ever since I realized that physics seems to tell us straight out that we live in a Big World, I’ve become much less focused on creating lots of people, and much more focused on ensuring the welfare of people who are already alive.

If your decision to not create a person means that person will never exist at all, then you might, indeed, be moved to create them, for their sakes. But if you’re just deciding whether or not to create a new person here, in your own Hubble volume and Everett branch, then it may make sense to have relatively lower populations within each causal volume, living higher qualities of life. It’s not like anyone will actually fail to be born on account of that decision - they’ll just be born predominantly into regions with higher standards of living.


[I]t seems in some raw intuitive sense, that if the universe is large enough for everyone to exist somewhere, then we should mainly be worried about giving babies nice futures rather than trying to “ensure they get born”.

John Broome in Weighing Lives, pg 18:

The two topics [of extending life and creating life] are obviously connected in principle. Extending a person’s life and adding a new person to the population are both ways of bringing it about that more life is lived by someone. So in one sense they both do the same thing. Of course, there is a crucial difference too. In one case the extra living is done by someone who already exists, and in the other case it is done by someone who would otherwise not exist at all. Nevertheless, it must be a mistake to deal with the two problems in complete isolation from each other.

See also “The Least Bad Solution”, which is also related to life extension and overpopulation.

Quotes from Holden on x-risk.docx:

Holden: So there is this hypothesis that the far future is worth \(n\) lives and this causing this far future to exist is as good as saving \(n\) lives. That I meant to state as an accurate characterization of someone else’s view.

Eliezer: So I was about to say that it’s not my view that causing a life to exist is on equal value of saving the life.

Holden: But it’s some reasonable multiplier.

Eliezer: But it’s some reasonable multiplier, yes. It’s not an order of magnitude worse.

Holden: Right. I’m happy to modify it that way, and still say that I think this is a very questionable hypothesis, but that I’m willing to accept it for the sake of argument for a little bit. So yeah, then my rejoinder, as like a parenthetical, which is not meant to pass any Ideological Turing Test, it’s just me saying what I think, is that this is very speculative, that it’s guessing at the number of lives we’re going to have, and it’s also very debatable that you should even be using the framework of applying a multiplier to lives allowed versus lives saved. So I don’t know that that’s the most productive discussion, it’s a philosophy discussion, often philosophy discussions are not the most productive discussions in my view.

See also Eliezer again (same PDF, pg 41):

I suspect I may end up, either neutral or favoring use of resources for existing people, rather than creating new people, but that’s only true because I think you can get at least as much utility out of using more resources for existing people, rather than creating new people.

Page 40 contains the painting analogy by Holden, which is quoted in a post by Carl Shulman.

  1. The more general question is: does the value of life start to diminish once you’ve lived for long enough, or does it compound over time?

  2. de Grey, § We’d be denying future generations the right to be born:

    Let’s be fair and recognise that the limiting factor [of conception] is the number a woman can have; it’s still clear that we could raise the birth rate by at least a factor of 10 if we chose. Why don’t we? Because we feel that the quality, and indeed the probable length, of those lives would be poor, and we feel that giving those who are born a respectable quality and length of life is morally better than maximising the number of births. So humanity’s position on this matter is already quite clear. And all we’d be doing by eliminating aging would be adding at most 10% to the rate at which we’re denying hypothetical people the right to life.

    Secondly, even if we were to conclude that hypothetical people had some right to be born, that wouldn’t be enough. What we’re asking here is, do such people have so fundamental a right to be born that those who are already alive should lay down their lives in order to allow those people to be born? You can fill in the rest yourself: it’s just as above. We have already voted with our actions; the elimination of aging would not herald a new dilemma in this regard.

  3. Caplan writes in “Where Are the Pro-Life Utilitarians?”:

    When I present the utilitarian case against abortion, people normally reply, “But that implies a further moral duty to have tons of babies.” They’re right. From my perspective, that’s yet another convincing argument against utilitarianism. Creating life is a prime example of what utilitarians conceptually reject: actions that are morally good but not morally obligatory. But given utilitarians’ notorious willingness to bite bullets, why should they demur here?

  4. Daniel Callahan. Setting Limits: Medical Goals in an Aging Society. 1987. Simon and Schuster.