Martin Rees, the British cosmologist to whom the phrase “absence of evidence isn’t evidence of absence” is attributed, said in an interview with Kings Review that even though it took us four billion years to get to where we are, humans aren’t the apex, but a mere rung in the evolutionary ladder.
Most people are aware that we’re the outcome of about four billion years of evolution. But I’d guess that they tend to feel that we humans are the culmination—the endpoint of the process.
No astronomer could think that way. We know the future is, at least, as long as the past: the Sun is less than halfway through its life—the universe may even have an infinite future.
So, to us, it seems natural to suppose that humans are just a step on the way, maybe not even a halfway stage in the emergence of ever greater complexity. And this post-human evolution could happen here on Earth or somewhere beyond Earth; it may be silicon-based rather than organic.
This realization gives us a different perspective on humans, but also perhaps an extra motive for concern about the future, because we realize that a catastrophe could foreclose an immense post-human era.
Any creatures, who will be alive to witness the death of the Sun won’t be human—they could be as different from us as we are from protozoa, because the time between now and then is longer than the Earth’s recent age.
Indeed, future evolution is going to take place not on the Darwinian time scale, of natural selection, but on the technology time scale, because we’re obtaining the capacity to modify the genome.
We might try to constrain such developments on Earth, but if there are communities, a few centuries from now, living on other planets or on asteroids, we’d surely wish them good luck in deploying all known science to adapt their progeny to an alien and hostile environment.
h/t: KINGS REVIEW