Or are there inevitable limits to growth of complex decision-making structures, including and beyond biological ones?
Stephen Arthur has written a very interesting article, “How I Know There Are No Aliens” (https://medium.com/@sxarthur_80712/how-i-know-there-are-no-aliens-d85e826c41f1), in which he begins
“The Great Silence contradicts what should be. Intelligent alien species should be millions or billions of years more advanced than us because most star systems are several billion years older than ours. It should only take a million years for one of these aliens or their machine descendants to colonize the galaxy, whether directly or through self-replicating robotic probes. So techno-signatures from their god-like astro-engineering should be abundant.”
and concludes after much plausible argument,
“Despite a seemingly atavistic, anti-Copernican view, I think we must accept that we are alone.”
He may be right. Nevertheless, I find it implausible that among the likely trillions of habitable planets in the billions of galaxies in the known universe, none has evolved forms of life with brains, sensory organs, and action capabilities functionally similar to ours. So the fact that we have, so far, not detected signs of advanced intelligent beings may be due to inevitable limitations on the ability for such aliens, and us humans, to grow to an extent that beings of similar intelligence can observe them or us.
Despite what we may imagine and wish, there are severe limitations to how far, fast, and cohesively we humans could spread as biological organisms from our home planet. The speed of light is still, as far as we know, the upper limit at which information can travel, and well above the speed at which we could travel and survive as living organisms. If we were able to launch spacecraft to ultimately colonize planets in other solar systems, our human supecies would lose cohesion as any surviving colonists would lose the ability to communicate usefully with Earth or other colonists. Furthermore, our biological nature would make it very unlikely that any of the intended colonists or colonies would survive for very long.
Some people, like the physicist Freeman Dyson, have imagined that intelligent beings might…