Consider three very different scenarios:
A) We are totally unique in the universe, the only intelligent life anywhere.
B) The universe teems with intelligence. Galaxies often form connected communities of different intelligent species.
C) Simple life is common, but intelligent life is typically very short lived. Intelligence is common enough, but doesn’t persist long enough for intelligent species to meet in outer space.
All of these are live possibilities, as far as we know. Nothing we know about the shape of the universe rules out any of them. But it’s curious what a different light each scenario casts on our struggle to not destroy ourselves.
A) If we’re the only intelligent species that has ever been, our survival is of paramount importance. Burning through a planet or two is immaterial in comparison. I find this scenario to be the least likely.
B) If we’re just a few generations away from being inducted into the Galactic Federation, destroying ourselves wouldn’t, in the grand scheme, be as tragic. It would be more tragicomic – still sad, but in an hilarious bumbling way. It would also be immoral for us to prioritize the survival of humans over other species. Stripped of our status as unique in space and time, it seems to me our importance relative to the rest of the biome would be diminished. Conservation efforts make the most sense on this scenario.
C) This is the most interesting scenario to me, and it strikes me as just as likely as the other two. Imagine that the universe is positively sodden with simple life; algaes, bacteria, fungi, etc. Our own planet spent a couple of billion years covered in not much more, as far as anyone can tell, than stromatolites.
Maybe that level of life is simply everywhere. More complex things like plants and animals could be much rarer, but still reasonably well dotted around the universe, appearing where conditions are favourable.
And now imagine that intelligent life shows up regularly enough, but inevitably is snuffed out shortly after it appears. Intelligence is simply too volatile to survive on geological time-scales. Sometimes it lasts a few few thousands of years, sometime nearly a hundred thousand. But inevitably, intelligence tears itself apart. Like a supernova, it expends itself in a magnificent flash. Or, dumb luck crushes it in its flower, blasted by a meteor or some other random event. Either way, intelligent itself is mortal.
With this scenario, our conservation efforts look noble enough, but ultimately misguided. It’s like a 95 year old trying to quit smoking. What we should be doing instead is really enjoying the view, savouring the little time we have left. It’s a rare and precious thing that we should have happened to wake up in the world, and the really tragic thing would be to waste that wakefulness on panicked clinging. A graceful exit would be preferable, without too much fuss. We should make reasonable efforts to keep ourselves going, but no extreme measures. And the stylish thing to do would be to avoid doing too much damage to the rest of the biosphere in the process of our extinction.
The amazing part, the really awesome, terrifying bit, is that there really is a real answer to the question of how much life there is in the universe, and how much of it is smart. And it’s a good bet that we’ll never know what it is. We have to figure out what to do with ourselves in this profound ignorance.