>>16789781
>Then it's pointless to look for them because if a civilization that could build one existed they'd be here with us already.
Why do you assume interstellar flight is "easy"? There's no known method of "folding space" outside of science fiction and the purest form of scientific speculation, so you're limited to one-way voyages that take decades or centuries. In the meantime, your civilization is still expanding at home...just because Europeans sailed to America doesn't mean Europe went away or started depopulating.
So you wind up with an interstellar civilization clustered around its original home star, which will have gone "full Dyson" in the nearest systems by the time its gotten more than a few hundred light years from its origin. And since space is kind of big, there's no reason to think that if such a civilization was even a quarter of the way across the galaxy (tens of thousands of light years) they'd have reached us by now or would want to send anything more than some nosey little AI probes. As opposed to the "Dark Forest" hypothesis, maybe conquest isn't their thing, and even if it is, don't you want to fortify the home worlds? Which requires, I don't know...a Dyson-tier energy collection system to power your weapons?
And on top of all this, consider that we're already looking at becoming an introverted civilization, as AI will soon be able to create entire virtual worlds much funner than the real shit out there...which requires energy, which requires energy collection, which might require a Dyson-scale collection system. Altman is absolutely right.
