Do you think a theory of quantum gravity will reconcile relativity and quantum mechanics?
A simple (relatively speaking) quantum field theory of gravity was developed back in the 60s. It has GR as a low-energy limit, so the two can be considered effectively reconciled. The only problem with it is that it is non-renormalizable, which means that it breaks down at sufficiently high energies (which, by the way, we’ll probably never see in an accelerator). Fermi’s theory of the weak interaction had a similar problem before it was fixed. So it’s a good effective theory, but there’s probably something more that we haven’t worked out yet. Moreover, since gravity is so weak, it’s unlikely that we’ll ever actually find a graviton to conclusively confirm that gravity is quantized as the other forces are. Quantum entanglement and superposition don’t pose any particular problems for physics right now. The observed phenomena are well explained by existing theory. Cosmic inflation, on the other hand, is a big mystery–as are dark matter and dark energy. They provide the motivation for a l
