[ 12/1/21 ]
In the sense of growing at a fixed rate – that is impossible. At current growth rates it is less than 3,000 years before we reach the point that we need to be expanding at the speed of light to reach new stars to meet the growing need for energy. And there is no way to do that as the energy required for such accelerations would require a vast reduction in population.
If the rate of growth is continually reducing, so that it asymptotically approaches zero, then it is possible to sustain growth in a sense, and stay within the energy budget available in this solar system.
It is possible to limit reproduction to something less than unity, and maintain stability, something less than one child per person (on average, over a lifetime), accompanied by indefinite life extension.
Indefinite growth such as we have seen in the human population for the last few hundred years is not an option in any real universe – the physics and mathematics is beyond any reasonable doubt.
And if we accept the mathematical and logical and physical reality that the survival of all new levels of complexity is based upon new levels of cooperation, then we could build a high technology civilization in this solar system that would contain several trillion human beings living very high technology and interesting and secure lifestyles with reasonable degrees of individual freedom – each individual with the option of living on indefinitely.
And the logic of games theory is clear – there are no systems based in competition that deliver the sort of security that gives potentially very long lived organisms a reasonable probability of living a very long time. Longevity demands cooperation – the logic of that is beyond any shadow of reasonable doubt (as someone who has spent 48 years exploring the strategic spaces available), since realizing after completing 3rd year biochemistry that indefinite life extension was logically possible).