Initially, I can say that when I read the two alternatives:
A Time-civilization where, “A mere hundred thousand people live sustainably for a billion generations before finally going extinct”
A Space-civilization where, “A trillion people spread across a thousand planets live for only a hundred generations, then go extinct”
I also initially thought that I would prefer the Time civilization over the Space one..
Then I thought about it, however, and realized that this was a biased portrayal. The bias–somewhat obviously–came from the use of the word “sustainably” which not only definitely has a positive spin on it, but which is not balanced with anything on the other side.
This is unfair–or rather–it’s like stacking the deck.
Interestingly, however, this view of “sustainability,” whereby it is predicated on an entirely stable population is not necessarily so positive if you dig a bit deeper and focus on the “stability” aspect of this population. Specifically, there are two things to think about:
A) How does one keep a population at a permanently fixed number. Nowhere in nature–or in any civilization that we have ever known–is it true that people or animals remain in perfect harmony with their environment in anything like the way that is assumed in this thought experiment. Rather, populations grow and fall in a rather noisy fashion and–given the chance–it will always attempt to expand. Knowing this, the Time-civilization sounds a lot more like some magical-story folk–maybe like Tolkien’s elves–than anything realistic… and that might indeed explain some of its initial appeal.
B) On the other hand, there have been some instances of “sustainable” populations that have maintained fixed populations over long periods of time on earth, but the methods by which they did this were not, in any fashion, all that idyllic or even all that pleasant. The most obvious example I know of can be found in Jared Diamond’s book, Collapse, and it involves the tiny island nation of Tikopia. This isolated and extremely small island in the pacific maintained a constant population around 1300 people for over 500 years, I believe, and being cut off from the rest of the world, it fit the definition of “sustainable” and stable to a T…
However, this did not mean that once a person died, someone was allowed to be born or anything like that. Rather, people were just born–even if they were spaced out a bit in a conscious fashion–and if there were too many mouths to feed, then the island practiced infanticide. In addition, as Diamond notes, it seems clear that when the aforementioned practice didn’t work, and an “excess” population of adults existed, these groups were then often told to “go take a hike,” because there was no land to support them, so they were sent off in boats into the pacific in some direction to hopefully find some other island… (and almost certainly dying in the process…).
Taking these two things into account–the Time-civilization seems a lot less fun than it initially did. Indeed, it seems rather authoritarian and fascistic in a rather unpleasant way.
Finally, one might note that the Time-civilization doesn’t actually fit the model for evolution of species in any way. Populations don’t just remain stable and unchanging for a billion generations–which as one commenter on the original site noted was technically longer than the age of the universe (~20 billion years..)–but rather that all creatures we know of try to spread and as the populations diverge over geographic space, they change into other populations and species. Thus, this comparison seems even weirder and more stilted, because the chance of some 100k population remaining in one place and not being accidently wiped out within 20 billion years (our sun won’t last that long) is totally unrealistic.. In other words, the Time-civilization in reality would almost certainly go extinct by its very nature long before the Space-civilization did, because while the scenario/thought experiment says that all of the trillion people over many planets just up and die, what would be more likely to happen is that something would kill most of them, or the different people on different planets would start diverging into different species…
Anyway–while this was quite an interesting thought provoker–the scenario and results in the original post needed some more thinking and processing…