> If our ancestors would have made the rational assessment that there is unlikely to be a predator hiding behind the bush, that would have worked only as long as it worked, until one day they got eaten.

That wouldn't have been a rational assessment, because it wouldn't have been an accurate assessment of the risks of being wrong, and the behavior required to avoid them.

If there's only a 1% chance that a predator is behind a bush, and that predator might eat you, it's absolutely rational to act as though there is a predator. You'll be seeing lots of bushes in your life, and you can't escape from those 1% chances for long.

The same thinking is why it would have been rational to try and avoid global warming 30 years ago. Even if the science was not settled, in the worst-case scenario, you'd have "wasted" a bunch of money making green energy production. In the best-case scenario, you saved the planet.