How are Dark Mtter and Consciousness different from Spirit?

[Jackalope]

Ahat we know about dark matter:

D = \int (1+z) v dt = 2(c/Ho) sqrt(3*k*(1.947 K))/mc2) + ...

which gives D = 100 Mpc for mc2 = 5 eV in a critical density model with Ho = 65. Thus neutrinos can free stream out of the perturbations that make galaxies and cluster of galaxies, but will remain in the perturbations that make superclusters. Because this behavior is caused by the thermal velocity of the neutrinos, this form of dark matter is called Hot Dark Matter

If we have an exact formula for how neutrinos interact to create different forms of dark matter then it's not much of a big mystery. This gives us a stronger argument than "It exists because we  would have a problem if it didn't."

I'm going to let Alex comment on this because he's far more qualified than I to do so.