In particular I don't like the language used to talk about dark matter where it presupposes its existence (implicitly or explicitly as a particle). Here's what NASA says (from a search summary):

> Scientists have overwhelming indirect evidence for dark matter. However, its nature remains a mystery. Alternative theoretical explanations for the effects of dark matter, such as modifications to the theory of gravity, don't fit with observational evidence.

I interpret that to actually be saying that we have evidence for a cause (of gravitational warping of space) not explained by known matter, and the mysterious properties of the hypothetical particle are defined by our observations.

However it reads as if we have evidence that the cause of the anomalous observations is caused by a particle that we have yet to discover. What I believe is true in the statement is that we have evidence for 'a cause' of gravitational warping that's not explained by visible matter. This is where I see 'dark matter' as a placeholder for the cause rather than being a theory. The theory part is the hypothesis that it's a particle.

In that comment thread there was a link to a video in support of DM[1] but there's a later video by the same physicist that says "Dark Matter is not a theory."[2]

What I'd like to hear are actual arguments/evidence for dark matter as a particle and not only as the supposed cause of observations. What constitutes a theory? Is it falsifiable--what predictions does it make? Remember that I mean dark matter as a particle, not merely the placeholder cause of observations.

[0] https://news.ycombinator.com/item?id=40963179

[1] https://www.youtube.com/live/8rok8E_tz8k

[2] https://www.youtube.com/watch?v=PbmJkMhmrVI