Is Modified Gravity Theory a Viable Alternative to Dark Matter?

[atyy]

GR may or may not be a useful quantum theory (it might have to be modified at very high energies), otoh it is not a manifestly inconsistent quantum theory, at least at this level of discussion.

I was just thinking along the lines of Donoghue's GR as an effective quantum field theory at low energies, needing a still unknown UV completion.

 

[twofish-quant]

For instance, Palatini f(R) gravity is an example, as well as many of the higher derivative theories, bimetric ones and so forth. You would have to insist upon a modification of quantum mechanics to get them to work.

So modify quantum mechanics. I don't have much of a problem with that.