But today's academic opinion also credits 1945 as the beginning of the new Post Modern Age ( in effect signalling the start of the decline of Modernity.)
So which is it ?
It is almost as if Modernity was marched out front and centre , given lots of medals and many heartfelt votes of thanks and then told " you're fired."
Almost exactly what happened to Winston Churchill, that archetypal Modern, in 1945 in point of fact.
The Modern Age, that heady mixture of science,technology and nationalism that some also call the second industrial revolution,
began in the 1840s and was still powerful until at least the late 1960s but was in its heyday between the 1870s and the 1940s.
WWII was its only totally 'modern' war - it shared wars like WWI and Vietnam with pre and post modernity values.
And it totally, totally, lost that war - at least on its own terms - to Mother Nature, to Reality, to life outside the cloistered laboratory.
The three memes that signal the shift from Modernity to Post Modernity...
The two words, memes really, always attached to the idea that 1945 mark a definite shift from Modernity to Post Modernity are Auschwitz and Hiroshima : I wish to add a third, Penicillin, in particular the unexpected (Plan B) success of natural penicillin.
The revenge killing of six million Jews marked a signal failure in Darwinian/eugenic biology, a Plan B for the failure of Germany's Plan A : to quickly conquer the weak species Russia and then to starve 30 million of its citizens to death so as to be able to fill their empty but fertile farms with new German settlers.
Hiroshima' death of an entire city by fire was a Plan B to the Allies' failure of their original Plan A, targeting only a city's key factories by precision bombing using Norden bombsights and Newtonian physics ( aka ballastics).
Natural penicillin, Martin Henry Dawson's contribution to the war, was also a last minute Plan B, because the Allied's original Plan A was to let patented, totally synthesised, Sulfa win the side war against bacteria - failing that , to let the chemists synthesise totally artificial, patentable, analogs of natural penicillin. But Daltonian chemistry failed the test and like the other two, never recovered.....