This was the October 1927 Fifth Solvay International Conference on Electrons and Photons, where the world’s most notable physicists met to discuss the newly formulated quantum theory. The leading figures were Albert Einstein and Niels Bohr. 17 of the 29 attendees were or became Nobel Prize winners, including Marie Curie, who alone among them, had won Nobel Prizes in two separate scientific disciplines.
This conference was also the culmination of the struggle between, on one side, Einstein and other scientific realists – who wanted strict rules of scientific method as laid out by Charles Peirce and Karl Popper – and on the other, Bohr and other instrumentalists, who wanted looser rules based on outcomes.[vague] Starting at this point, the instrumentalists won, instrumentalism having been seen as the norm ever since, although the debate has been actively continued by the likes of Alan Musgrave. (Wikipedia)