Longtermism and Population Ethics - The Case for Space Habitation
“In a nutshell, longtermists argue that future people matter morally just as much as people alive today; that there may well be more people alive in the future than there are in the present or have been in the past; and that we can positively affect future peoples’ lives.*”
Consider the following premises:
1) It is better for there to be many happy people rather than few happy people
2) The Earth cannot sustain indefinite human population growth without grave consequences for its inhabitants
It's good to be happy
According to theories of population ethics, population A is better than population B, since population A is larger and they have the same level of happiness.
More than simply a comment that it is better to be happy than unhappy, all things being equal (which I have to assume is undeniably true for the great majority of opinions), this statement posits that there is an intrinsic value in being a happy individual, regardless of any economic or utilitarian function. In other words, being a sufficiently happy individual is a good in and of itself. What's more, if there are two sufficiently happy individuals, it's even better.
More people living sufficiently good lives is a good thing to bring about. This is supported by the predominant theories of population ethics, which is the field of study that explores the ethics, policies, and comparisons related to the wellbeing of populations that may come about in the future. There is an intuition that people generally have when it comes to bringing new lives into existence, which is the intuition of neutrality; the intuition of neutrality describes the feeling of ambivalence that people generally seem to have about the question of bringing new lives into existence. There is however a caveat to this intuition, which is that people are not quite so neutral about bringing new, bad lives into existence, which they asymmetrically seem to be opposed to (as I would hope all people are). Furthermore if people were truly neutral about bringing even good lives into existence, they would be entirely ambivalent about making the future better, as such a proposition involves the creation of happy people instead of making currently living people happier†. This is a roundabout way of saying that if people want the future to be good for the humans living in the future, then they should implicitly be in favor of creating new, good lives.
Closely related to this is the idea that a large population of people living good lives is better than a small population of people living good lives. In the context of the total population of humanity, this means that from a population ethics standpoint it should be a good thing to increase the population of humans if we are reasonably sure that the future will be positive and yield the conditions for happy people.
The Earth has a capacity
The notion of more people is however in opposition to the all-too-popular idea that the world is overpopulated and that adding people is immoral (antinatalism), or even that reducing human population is a moral imperative (a frightening conviction). Despite the opinion of many people who seem to be certain that we are past the Earth's "carrying capacity", researchers cannot seem to agree on a figure to within the same magnitude, largely because it depends on what data and assumptions the researchers are employing, but also because of the current and future climate uncertainties.
Regardless of one's views on whether humans have surpassed this imaginary figure or whether we have room on Earth to grow, I think we can all agree that Earth's capacity is not limitless. At some point, either due to limited space, insufficient energy, faulty planning, or all of the above, the marginal value of additional humans on Earth would be negative.
Having our cake and eating it too
If more good lives are better than few good lives, while at the same time the Earth has some arbitrary human capacity, the solution seems obvious: at some point we ought to expand beyond the Earth. We must inhabit space.
“The Earth is a cradle of the mind, but we cannot live forever in a cradle.”
* Samuel, Sigal. (2021). Would you donate to a charity that won’t pay out for centuries? Vox.
† This is a consequence of chaos theory applied to populations. Any change in initial/early conditions will yield completely different results in a long enough timeframe; in the case of populations, the choices we make now will not only affect the wellbeing of people born in the future, it will also affect who is born in the future.
