Assuming we're the stupidest possible biological species capable of starting a technological civilization seems almost (though not quite) as wrong as asserting we're the smartest such. In both cases we're generalizing from a sample size of one.
For instance, I can imagine a technological civilization that was stupid enough to wipe itself out in a nuclear war, which we've so far managed to avoid; or to destroy its environment far worse than we have. I can also imagine a society that might be able to reach 18th or 19th century levels of tech but couldn't handle calculus or differential geometry.
It's not that we've seen a large number of biological species capable of starting a technological civilization and we're dumbest of them. It's that we've seen a large number of biological species incapable of starting a technological civilization and we're only slightly smarter than any of them.
We know we're at the boundary of being able to start a technological civilization because we can do it and we've seen biological species within an epsilon neighborhood that cannot.
Another month has passed and here is a new rationality quotes thread. The usual rules are: