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.
I would strengthen this somewhat for emphasis. Obviously it is far more likely in the 1750 case than the 1950 case via a conjunction.
I would strengthen this somewhat for emphasis. Obviously it is far more likely in the 1750 case than the 1950 case via a conjunction.