[ajross]

You want... more from a theory than that it fit the data? That's not how theories work.

I think what you're asking for is a lab-testable prediction from a dark matter theory. And no, we don't have that. It would be nice if we did, but we don't. We don't have it from MOND either, though, so I still don't get your denialism. If you don't want us to do science to figure this out, what are you asking for?

[mdorazio]

If your theory isn't testable, it's not a scientific theory. Period. It's either a hypothesis or it's faith. When you go around denouncing people for asking you to make a testable prediction it just makes you look bad.

[ajross]

Evolution wasn't testable for decades after Darwin's death. Continental drift's predictions are still awaiting results that won't come for another few thousand years. Newton's gravity took hundreds of years before it could be directly tested.

All those theories were merely fitting to data. Do you genuinely claim they were "unscientific"?

I repeat: the desire to reject a theory for aesthetic reasons is the "faith" side of this argument. It's OK to prefer a better theory if you have one. It's not OK to sling insults at the people who point out that it's the best theory we have.

[User23]

Fitting any arbitrary measurement is trivial via regression. The hard and useful part is making predictions.

Cosmology is not amenable to either predictions or engineering. There’s not even anything to deny.