AFAIUI (layman, at best) it's a bit of both. There are multiple independent[1] lines of evidence, some of those led to the formation of the Dark Matter model, o

AFAIUI (layman, at best) it's a bit of both. There are multiple independent[1] lines of evidence, some of those led to the formation of the Dark Matter model, others were since discovered and just so happen to also conform to that model. [1] Maybe that's really the big question here.