Off-planet

If the planet earth is the only source of space and resources for humanity, then ultimately of course the "limits to growth" argument is correct. But, obviously, that assumption is wrong -- ultimately, in fact, the only thing that limits our expansion into the universe is the speed of light, and even that is only the case given what we know now. Admittedly, that's a fanciful extension of a counter-argument, but the point is simply that as long as we don't limit ourselves to this planet, there are no discernible limits to growth.

This is the real reason underlying the need to get human beings back into space beyond the first few hundred miles. We've taken the first step, but that was some time ago, and now the idea of people actually living off the planet seems more science-fictional than realistic. Yet that's the only way in the long run that we'll escape a lapse back into a stagnant and rigid hierarchy, or civilizational collapse altogether.

Those opposing ongoing growth -- the "limits to growth" proponents -- often argue against a move into space, usually on the grounds that it's an impractical answer to real current problems, and that it's a false hope that simply distracts from those earthly problems. And they're right on the first point at least -- the effort to free ourselves from being planet-bound is a long-range one, and is certainly not meant as a solution to immediate problems on earth. But it's not only a real possibility and hope for humanity -- in the long range, in its reduction of resource and space pressures on the planet, it may well be, ironically, the best hope for the planet.

In that long range, however, there is another, more obscure, concern about human civilization, and that is the fragmentation of the human species into radically divergent forms resulting from the wide variation in their physical environments. Not an immediate or even intermediate concern, no doubt, but interesting in the way that it leads into a broadening of the meaning of "human" -- that too is part of the journey.