Sure, I didn't mean to provide a full treatment of the "should it have been invented?" question. I just wanted to point out that there are many possible lines of reasoning:
These are not necessarily exhaustive. To me the most compelling is number 2, although nuclear non-proliferation since the cold war has shown that we can coordinate to a large extent, so maybe 6 is true or would have been if there had been no WWII.
This is essentially the debate on whether a specific technology should have been developed. Many possible answers: it was likely inevitable anyway that at least one country would develop the bomb; suppressing atomic research to avoid it would have led to a poorer world; etc.
In any case we have somehow managed not to have a nuclear war, so even though there's a potential of tragicness, the bomb's invention itself hasn't been so bad in real terms (except for the people of Hiroshima and Nagasaki, of course).
Thanks! The nuclear bombings were obviously very tragic, though if we take the view that a progress-positive culture is the main criterion for tragicness, the development of the bomb may have been a pretty good period, since it led to nuclear energy and other innovations.
Assuming the Great Stagnation hypothesis is true, whatever happened in the 1970s to slow down science could be said to be our 3rd most tragic moment. But it looks like our civilization is self-aware enough to avoid a full return to stasis, so fortunately we're not quite there yet.
Basically the exact same thing I said a few days ago! Possibly the thing to do would have been to convince the Athenians to listen to Alcibiades just before the battle of Aegospotami, when Athens lost most of its fleet.