[FeepingCreature]

My whole point and the emphasis on why I brought it up was that yes, the letter was about a "hypothetical" danger they had no way of "proving".

By any reasonable standard, at that point the possibility of nuclear fission was well established. But the argument is that there is no central committee that defines the reasonable standard and checks theories against it. It's all just opinion, and that specific opinion can be arbitrarily goalshifted.

I'm not saying the letter was about a hypothetical danger they had no way of proving, I don't think that. But that's specific to my interpretation of those terms, and I could easily see the exact same argument levered against the letter if that debate had been done in public.