[Filo]

I think of dark matter as a kind of cipher. A place holder that fills out the theory until they figure out what’s really is going on.

Exactly.

We don't even know that Dark Matter is really matter in the known sense of the word. All we know is that it acts like matter in that it causes gravity. . .

[AFPhys]

“All we know is that it acts like matter in that it causes gravity. . “

I disagree that even that much is “known”. I find ALL dark matter speculations very unconvincing, and the current “evidence” seems, to this physicist, as interesting but also greatly overreaching.