A very interesting topic which also gave me many hours of thought. Thank you for bringing it up.
I am left with the conclusion that consciousness could very well be divisible. There's possibility that the human brain could hold multiple consciousness, each one truly as real as the the one you know as you.
I think this is perfectly normal. How else would it be possible to empathise with other people and perspectives? It would not be possible at all. When we follow a play (film, theatre), we are able to recognise each character as peculiar and we, as observers, can understand each of these characters in their feelings and actions. In my view, a person who can put himself in these different roles is a human being precisely because he has an awareness of himself, which at the same time enables him to experience and make himself aware of those of others as well. The division of the self into many selves, which is also considered schizophrenic, is nevertheless primarily not pathological, but normal. At least as long as one does not insist that the people or imaginary figures that exist in one's consciousness must be materially visible to others.
If you have ever written a book or a screenplay, you will notice that the characters develop a kind of life of their own and that as an author you feel a certain amazement that you, as the creator of the characters, write things that they do that you did not necessarily intend precisely. There is a blurring between character and author. I think this is the effect of being able to take on multiple personalities and surprise yourself in a way that is hard to describe, that you didn't anticipate the outcome of a scene.
Since the transition from homo sapiens to man, his awareness of himself is a kind of curse and blessing at the same time. This ability brings the individual into constant conflict with the group, the many others, where he makes (must make) a distinction between group will and self-will.
I'll copy you some paragraphs from a book, I am right now reading, in another comment.
Greetings.
RE: Defining the Mind: Divisibility