I am new to this forum and relatively new to learning physics itself. I have a very basic question. What is the motivation for looking for a unified theory of quantum gravity? Other than the aesthetics of having a unified understanding of reality, do we have any physical or mathematical reason to believe they can be/should be unified? Both are standing strong for almost a century of real/thought experiments with probably zero error. We have not seen any deviations in the predictions of both. I can see a small problem in gravity in flat galaxy rotation curve. But honestly that doesn't look like a GR failure. GR is better than that. :) QM is 100% good, AFAIK. So someone could naturally think to leave them alone as 2 seperate laws of nature. Given all this I am sure there must be reasons to believe in a unity. But i would really honestly appreciate if someone could explain it, mathematically or otherwise. Thanks for reading.