Dark matter in the terms of something missing from what we know about the universe probably exists in some form, even if it literally is a type of existence that relies on non-existence.

• Dark matter is the term given to matter which, if it does exist, is unobservable due to its noninteraction with electromagnetic force (light). Scientists infer its existence from the mismatch between galaxy rotation speed and the gravity of the observable matter for each. The speeds are too fast for the observed amount of gravitational generation we see; galaxies should have torn themselves apart long ago.

• Classically, scientists have wondered if dark matter might not be composed of some as-yet undiscovered subatomic particles, often referred to as weakly interacting massive particles (WIMPs).

• Additionally, explaining dark matter may require tweaks to general relativity. It's possible dark matter in the conventional sense doesn't exist. New theories suggest the problem is fixable mathematically using what's referred to as the modified Newtonian dynamics theory (MOND). MOND postulates that gravity creates a small acceleration for large, galaxy-sized objects, dispensing with the need for dark matter.

• Personally, I still wonder whether dark matter, inferred at any point in our scientific history, may literally be a different type of "non-existence" that interacts with our universe "of existence" in a way that makes it appear undetectable to us. This is an extreme hypothesis at the far end of reasoning, however. But I do like to consider it a possibility:

• Even if new theories get rid of new the need for dark matter, I sometimes wonder whether that might simplify things too much. For example: The existence of dark matter was at some point something missing in our explanation of the universe. Science can and should dispose of models which fail to explain things fully or end up being falsified in general, but philosophically I think we can rightly wonder what it is we might lose when we scrap a problem entirely after seemingly having solved it. Just my opinion, but I wonder if there might, indeed, be a whole bunch of different aspects to things which we miss out on because we sometimes consider things solved. That is, the original grounds of the problem may still exist, even if they're confined to our original/more limited understanding beforehand, and in those original confines, there may occasionally be a different way of viewing everything which could still be valid in some way. We might miss out on these potential insights if we focus too much on fitting things into some kind of arbitrary whole: an always-forward-looking mindset that progresses linearly and with a sense that "all things become more settled in time" while occasionally neglecting those concepts which fell to the wayside in its hyper-focused wake.