Mach’s principle says that the mass of the particle knows something about the fixed stars far away, and that angular motion relative to the fixed stars is an absolute motion, and that mass is somehow generated by interaction among all the masses. In isolation, perhaps, a single particle in an otherwise empty universe would have no mass.

I suggest something similar applies to self-consciousness. It sounds like it’s an attribute of a single person. But perhaps self-consciousness is a property of a system, only arising out of a community, and wouldn’t exist in isolation, and therefore cannot be isolated in one person’s brain. For a poor analogy, think of friendship. You can’t experience it unless there are other human beings. The notion of being your own friend in a universe of 1 cannot occur. It’s a relation that implicitly involves the existence of other similar beings. In isolation (ab initio) a single person would have no self-consciousness.

Scruton: I am I to myself only because, and to the extent that, I am You to another. Every I requires a You, and the two subjects meet in the world of objects.