These brilliant men argued for a decade and could not resolve it so they decided to bury the questions. It was not unreasonable in that context to accept that they did not know the answers but the theories work so let's use it and see where it leads. I am sure the hope was that the answers to the philosophic questions would become clear as our understanding of the new physics grew. There was a lot of work to do aside from the philosophic questions. Fast forward 100 years and here we are, the philosophic questions are still unanswered, and the Copenhagen interpretation has hardened into dogma banning any discussion of fundamental questions in physics. I have respect for Smolin for at least trying to re-raise these important questions.
[1] I am of the view that philosophy is distinct from physics in that it studies the nature of reality and knowledge, thus it applies to ALL fields not just physics. WHAT do we know and HOW we know is the more (or the most) fundamental science. The physicists are throwing out the baby with the bath water when they reject philosophy en masse instead of rejecting bad philosophy.
The quote was by Zlatko Tesanovic, a brilliant and witty theorist who sadly passed away a few years ago. Here's a link to a page of some of his other quotes, as recorded by his students. IIRC he said the integrals quote when I was the TA for his statistical mechanics and thermodynamics class.
That's a quintessential philosophical question.
A philosophical assertion about what should be valued, if ever there was one.
It's true that science and philosophy did come from a common discipline (my undergrad uni originally had a Natural Philosophy dept that only became a physics department somewhere between 100-150 yrs ago).
Though I thought one of the physics professors when I was in grad school said it best : "Physics is philosophy with integrals".