Hi Gerald,

Interesting question! Regarding IIT, I don't think it's the only theory of panpsychism because as far as I understand panpsychism "everything is conscious" to an extent.

I think the universe would be able to have a substrate for networks though perhaps just with greater space between them, and operating at a slower speed, albeit with information still being passed at the speed of light. Our own brains are not "solid", even what appears to be solid flesh is mostly empty space on an atomic level.

If you think about Dark Matter and Dark Energy, it seems that it actually takes a form that looks quite similar to neurons in a brain. Perhaps Dark Matter is the "substrate"?

https://around.uoregon.edu/content/uo-physicist-shine-light-dark-matter-pub-talk

https://phys.org/news/2019-09-artificial-intelligence-probes-dark-universe.html