What about a pure Soviet entry into the war? You have to look at what happened to Poland and Eastern Europe when the Soviet army invaded. Once again, by any metric, this was the best possible outcome at the time.

But it was unquestionably a local maximum - the best solution at the time, with horrific consequences afterward.

While the debate on the bomb is not and never will be settled, I'm not sure I'd call the bloodshed caused by Hiroshima and Nagasaki to be unnecessary: it ended up a war that had caused so far millions of death.

And what social epistemology, actually?

Indeed it would have been better for me to focus on the decades of existential fear rather than the immediate bloodshed because, as demonstrated, the debate descended straight to the usual about the morality of dropping the bomb in WWII.

>And what social epistemology, actually?

Karl Compton and Leo Szilard whispering in Vannevar Bush's ear about the threat that the prospective threat that a German atomic bomb would pose. Vannevar would later make the case that the physicists would have done these feasibility tests anyways with or without his support, but this is a (somewhat biased) counterfactual and therefore incapable of being evaluated.

The whole episode demonstrates that it is by responding affirmatively to the 'choice to learn' - in this case whether a unique embodiment of already known physical properties is _really_ feasible - which finds us crossing the technological Rubicon of runaway doomsday device development.

Vannevar would go on to defend his actions in saying that it was good that such a horrific capacity was demonstrated in such a 'spectacular' way. His words in his autobiography, "Pieces of the Action" strive to cement the legacy of his gift to the world:

  "The advent of the A-bomb is generally regarded as a catastrophe for civilization. I am not convinced that it was.  With the pace of science in this present century it was inevitable that means of mass destruction should appear.  Since the concept of one world under law is far in the future, it was also inevitable that great states should face one another thus armed. If there were no A-bombs the confrontation would still have occurred, and the means might well have been to spread among a a people a disease for a chemical that would kill or render impotent the whole population.  History may well conclude, if history is written a century from now, that it was well that the inevitable confrontation came in a spectacular way that all could recognize, rather than in a subtle form which might tempt aggression through ignorance.  At least we all know, we and the rest of the world, that there are A-bombs and what they can do."