The hypothesis was first put forward in 2014 by cosmologist and theoretical physicist Max Tegmark from MIT, who proposed that there's a state of matter - just like a solid, liquid, or gas - in which atoms are arranged to process information and give rise to subjectivity, and ultimately, consciousness. See his paper: https://arxiv.org/abs/1401.1219.
Now, assume that Consciousness is the state of matter. There is a theory that Consciousness is expanding. So the question is that if you believe in the ontology of eternalism and Tegmark's Theory of Consciousness, then Consciousness had its own Big Bang (inflation type theory for Consciousness), hence there must be another type of nothingness before of Big Bang of Consciousness.
How to explain nothingness in the Consciousness theory of Tegmark?
In his Book entitled Life 3.0: Being Human in the Age of Artificial Intelligence - Tegmark mentioned that since there can be no meaning without consciousness, it’s not our universe giving meaning to conscious beings, but conscious beings giving meaning to our universe.
If all the wonders of the cosmos carry on without a conscious mind to appreciate them, the universe will be rendered a meaningless “waste of space”.
History: The Idea of Consciousness is the state of matter is originated from Agni Yoga.
See page 5 ,number 11 of the paper of the multidimensional Consciousness by Sergey G. Dzhura
Jay Alfred also studied Consciousness as a state of matter. See his book: Alfred , J. (2007). Dark Plasma Theory – Biology. Canada: Trafford Publishing.
I read it here page 4. Line 18: "Philosophising consciousness from string theory" Ningombam Bupenda Meitei