I’d say that at this point we are largely ignorant of the odds of intelligent life existing in a solar system. While at least some basic forms of life ought to be plentiful in the galaxy, the conditions for evolution from simple life to intelligent life (that is, civilization-building life) just aren’t understood to the level that would be required for ANY probability estimate to be given. Note that I’m not saying intelligent life is rare; I’m just saying that both scarcity and abundance of intelligent life are consistent with our current state of knowledge.
But that’s just the prior probability. I can still say that we have strong evidence that the probability of a given solar system having intelligent life is much, much lower than one in 150,000.
I admit that a Dyson sphere seems like an arbitrary place to stop, but I think my basic argument stands either way. If any intelligent life was that common, some of it would spread.
I’d say that at this point we are largely ignorant of the odds of intelligent life existing in a solar system. While at least some basic forms of life ought to be plentiful in the galaxy, the conditions for evolution from simple life to intelligent life (that is, civilization-building life) just aren’t understood to the level that would be required for ANY probability estimate to be given. Note that I’m not saying intelligent life is rare; I’m just saying that both scarcity and abundance of intelligent life are consistent with our current state of knowledge.
But that’s just the prior probability. I can still say that we have strong evidence that the probability of a given solar system having intelligent life is much, much lower than one in 150,000.
Or at least intelligent life that modifies its home system in a way that is visible from thousands of light years away.
I admit that a Dyson sphere seems like an arbitrary place to stop, but I think my basic argument stands either way. If any intelligent life was that common, some of it would spread.