Are Spirits Dark?

We see stars and galaxies moving in ways they should not; … we deduce the existence of hitherto unobserved substances, provisionally called dark matter and dark energy. … [Dark matter] outweighs ordinary matter by a factor of 6 to 1. Galaxies and galaxy clusters are embedded in giant balls, or “halos,” of dark matter. … It has to consist of particles that scarcely interact with ordinary matter. …

Could there be a whole sector of hidden particles? Could there be a hidden world that is an exact copy of ours, containing hidden versions of electrons and protons, which combine to form hidden atoms and molecules, which combine to form hidden planets, hidden stars and even hidden people? …

Hidden worlds cannot be an exact copy of our visible world. … Halos would have flattened out to form disks like that of the Milky Way. … [They] would have affected cosmic expansion, altering the synthesis of hydrogen and helium in the early universe. … That said, the dark world might indeed be a complicated web of particles and forces. … Dark matter may be accompanied by … a hidden version of electromagnetism, implying that dark matter may emit and reflect hidden light. … The observation that small galaxies are systematically rounder than their larger cousins would be a telltale sign of dark matter interacting through new forces. …

The theoretical case for a complex dark world is now so compelling that many researchers would find it more surprising if dark matter turned out to be nothing more than an undifferentiated swarm of [weakly interacting massive particles]. After all, visible matter comprises a rich spectrum of particles with multiple interactions determined by beautiful underlying symmetry principles, and nothing suggests that dark matter and dark energy should be any different. (more)

Many people have a strong intuition that around us there are “spirits”, i.e., unseen intelligences who are usually hidden, but who sometimes touch our lives and world. The hypothesis that these spirits are made of ordinary matter and big enough to see is extremely hard to square with common observations. And the hypotheses that they are made of ordinary matter but too small to see, or usually hiding in space or deep underground but popping into our areas on occasion, are also pretty hard to square with expert observations. We keep getting better at seeing things, and see little evidence of anything remotely similar. Intelligences must eat something, defecate something, have evolved from something, etc., all of which leaves traces.

But physics today does offer one plausible place for a spirit hypothesis, in “dark matter.” We know that our kind of matter (electrons, protons, etc.) makes up less than 5% of the mass of the universe around us. The rest is a mysterious matter that interacts only very weakly with our kind of matter, but could interact more strongly with itself, and in complex ways. And while we know most of this dark matter cannot be made of heavy things that clump tightly like our matter does, a substantial fraction of it (say ~1%) could.

So there could well be complex intelligences made out of dark matter, and there might also be ways for them to rarely interact with our world, though such interaction would probably require them to exert great and careful efforts. And furthermore, since dark matter is a high priority research topic, if there is complex clumping dark matter we’ll probably know about it within a half century. Perhaps even a decade.

We thus face a unique chance for folks with strong intuitions for or against spirits to make testable predictions, and even put their money where their mouth is. Those who think spirits likely should think substantial clumping dark matter is likely, and there should also be many who think neither is likely. I’ll go on record saying I doubt any substantial fraction of dark matter can support complex structures conducive to the evolution of life. What say you?