If, as has been suggested, a majority of the Everett branches from our 1950 destroyed the world, then it is equally true that a majority of the Everett branches from our 1750 in which there is someone still alive in 2010 failed to contain probably-world-destroying technology.

Equally true? So in other words, the Anthropic Shadow is indefinitely long? I wonder what Nick Bostrom would make of that assertion.