[throwawaymaths]

This is terrible. Of course dark matter is a theory. Saying it's just a bundle of observations is like saying "1) lee Harvey Oswald had interactions with the CIA and 2( he killed JFK", and claiming "hey man, just making two innocent factual observations". No, of course not. By shoving different things together you are implying a causal connection, which is exactly a hypothesis.

This kind of a wordplay shell game is really bad for science

[aeturnum]

Things fall towards the earth. You can check that they do right now by dropping something. That things fall towards the earth isn't a theory - it's an observation. Gravity - the most popular explanation for why that happens - is a theory!

"Dark matter" comes from a group of observations that consistently suggest there is more mass in the universe than we can account for. The fact that we keep observing it is not the same thing as an explanation for the observations. There are also theories that try to explain dark matter! But the fact that people observe it is not a theory.

[throwawaymaths]

I'm going to repeat, clearly. The observations themselves are not a theory. Grouping them together is.

> That things fall towards the earth isn't a theory.

Actually, it is.

Any given object falling once is an observation. Noticing more than one thing falling consistently is a theory.

[shiroiuma]

"he killed JFK" isn't an observation: there's no witnesses that ever testified to this. You don't know that he killed JFK, and in fact new evidence casts serious doubt on it (it was here on HN recently I think).