Can general relativity be considered a quantum theory? If yes, what are some examples of its application in that field? - Quora
https://archive.ph/OVBQS

Why does Schwartz in his textbook say that quantum field theory is a mess? He says its foundations are flimsy and many derivations are unsatisfactory (Paraphrased) yet he said it explained a lot. What are we missing? - Quora
https://archive.ph/Dqzf9

How far are we away from describing general relativity, quantum mechanics and the expanding universe in just one theory? - Quora
https://archive.ph/pQcD2