The subtleties of quantum theory are for the most part of little practical consequence for cosmology. Gravity drives the expansion of the Universe, the formation of galaxies, and the way matter condenses into planets. And gravity as depicted by Einstein's general theory of relativity is classical physics par excellence. Relativity assumes that mass and energy are infinitely divisible, and that the geometry of space and time is smooth and continuous down to the smallest scales. But there's one moment when quantum theory can't be ignored - at the very beginning of the Universe, the big bang itself.
This is a companion discussion topic for the original entry at https://vault83.com/threads/strings-and-singularities.25/