How are Dark Mtter and Consciousness different from Spirit?

[Jackalope]

Dark matter is posited because of the difference in what was expected and what was actually captured by the scientific equipment.. Spirits on the other hand, are usually just anecdotal things with no evidence other than what people say they've seen, like the Loch Ness monster and Yetis. Until there is some actual evidence it can be lump[ed along with all the other myths.

In what way does dark matter satisfy the discrepancy in the equation?

In short, observations of the rotational rate of spiral galaxies does not jive with the expected rates under Newtonian theories of motion as modified by Relativity.

There are really only two reasonable explanations for this: our understanding of the relationship between mass and gravity is wrong, or there's more mass present that we (so far) can only observe by it's gravitational interaction with matter that we can see.