I seem to be missing the resources that describe how gravity is not found in quantum mechanics. What phenomena in quantum mechanics illustrate that gravity is [thus far] not a part of it? This is not a homework question. I know that gravity is incompatible with what we know about QM. What I DON'T know is WHY. I'm not interested in theories on quantum gravity. I have books about them and that's not what my question is about. My question is more about the reason we are trying to find quantum gravity in the first place. What is it SPECIFICALLY about QM that is not compatible with gravity? What QM behavior "defies" gravity?