We each have our own universe. Our universe is us - who we are, and what we are aware of. This 'me' (or 'you') universe exists in a dimension.
What is happening in the 'In Sight' dimension is the overlapping of universes. I am aware of John, John is aware of me, our universes have overlapped. Indirect overlapping is also possible: I am aware of table, Max is aware of table, our universes have overlapped - even if we are not aware of each other. If your universe overlaps with another universe, you are in sight. This is dimension one (1).
If your universe is not overlapping with any other universe (read: you are unique in your awareness), you are existing in the 'Out of Sight' dimension. This is dimension two (2).
The question now becomes: what is aware? Is your dimension of existence (at any moment) determined by your physical awareness alone (i.e. what you can see/touch/etc.)? Or does your dimension-determining awareness also include your mental awareness? Does my awareness of famine in the third-world effect my dimension? If physical awareness is the only one to count, do we need to be jointly aware of the same thing (i.e. the same stop sign), or can we be aware of the same thing in a different place (i.e. any stop sign)?
Although I am the one preposing this model of existence, I do not have the answers to the above questions. That said, they don't have much of an impact on the system. The definition of awareness changes the odds of your existing in the 'Out of Sight' dimension.
Regardless of your ratio of time 'in sight' to time 'out of sight', your universe is quite often overlapped with other universes (or it is always overlapped). If our universes are overlapped, they contain something that is the same. Uniqueness, therefore, is an illusion.
