> It would be, by fair, the biggest failure in modern science. So there is reason that alternatives to dark matter are held to a higher standard than dark matter itself, beyond simplicity - which dark matter no longer really is.
I don't think this is anything to do with a higher standard. It's more like Occam's razor. If there's an alternative explanation that will upend our whole understanding of gravity and cosmology, have at it. But such an explanation must come with something testable that shows it's true.
Here's an example of an alternative explanation, "a wizard did it." But that's not science, because there's no way to prove it. As a result, in the absence of a testable hypothesis, you have to go along with the one that does the least violence to all currently existing knowledge, surely?
I.e. what I'm saying is that it isn't on the Dark matter theory to prove itself. We already have observable gravitational issues that need something weird to be true. Dark matter is just the simplest explanation anyone can come up with that fits the facts. It's on any other theory to either throw out less of already-established science by being an even simpler explanation, or to prove it's justified in throwing out more by showing experimental evidence.
Or, to put it another way. I agree that dark matter isn't a simple theory. But there isn't currently a simpler one on the market.
Let's go back to the late 19th century and give the physicists of the time a peek of what would come to be the future of dark matter -- that it would not only end up needing to be a rather exotic form of matter, but that it would need to account for nearly all matter in the universe, along with all the countless negative conditions we can also now apply to its existence as a result of various experimental failures. Of course we would also give them the pros of dark matter in that it also explains, after substantial 'refactoring', some other otherwise difficult to explain issues. The dilemma that they then face is pondering whether this material seems more probable, or whether it might be the case that e.g. Newtonian dynamics is somehow missing something? For brevity, I'm sidestepping relativity.
I think you'll see a lot of the issues with alternatives such as MOND are a 'lack of elegance', yet we've happily accepted that the universe on a very small scale is far from elegant, so it seems peculiar to insist that on the very large scale it must behave with elegance. Another issue is that MOND generally also has a requirement of some dark matter, but the critical difference is it's just that - matter (including baryonic) that cannot yet be observed, not the increasingly exotic material that dark matter has morphed into. And it also only requires a small fraction of the amount that current dark matter does.
I tend to agree that dark matter is the most probable explanation. But, at the same time I think the resource allocation for dark matter as opposed to everything else is probably not the one we would choose if we were being completely impartial.
I don't think this is anything to do with a higher standard. It's more like Occam's razor. If there's an alternative explanation that will upend our whole understanding of gravity and cosmology, have at it. But such an explanation must come with something testable that shows it's true.
Here's an example of an alternative explanation, "a wizard did it." But that's not science, because there's no way to prove it. As a result, in the absence of a testable hypothesis, you have to go along with the one that does the least violence to all currently existing knowledge, surely?
I.e. what I'm saying is that it isn't on the Dark matter theory to prove itself. We already have observable gravitational issues that need something weird to be true. Dark matter is just the simplest explanation anyone can come up with that fits the facts. It's on any other theory to either throw out less of already-established science by being an even simpler explanation, or to prove it's justified in throwing out more by showing experimental evidence.
Or, to put it another way. I agree that dark matter isn't a simple theory. But there isn't currently a simpler one on the market.