Transition from time/space to space/time

[anagogy]

Why do you say 'almost?' isn't it "literally every" reality?

I say 'almost' to account for the fact that some possibilities cannot logically fully manifest due to the fact nothingness is not a real possibility. There is no reality where you don't exist, and the suddenly do exist for example. This is just my personal opinion, but existence is all there is, and all forms (explorations of limitation) extend from it and return to it. I wish there were better words -- these things seem so simple in my mind but sound complicated when put into words. So I would say: all realities that are possible are present.

Doesn't the higher self that interacts with you change constantly to be the one that is vibrationally compatible with its past self? Because you are never without a higher self - there is always a future you that arose as a result of your current state. The one that interacts with you must always be the one most compatible with you.

So then it is a different entity in the sense of timeline, but really it's absolutely the same entity. I guess I'm not comprehending how you and your higher self could even be separate at all, especially not from your higher self's perspective.

Again, it is more a case of my poor word choice. In some sense there is no separation between any being because we are all the same self.

The 'version' you interact with would be narrowed by what you 'know' about its identity. So the more you get to know it, the less latitude for different versions there would be. Knowledge restricts 'other' possibilities. Sort of like the particle and wave in the famous double slit experiment. If you 'look' or 'know' the specific actions of the particle, it goes through one slit, if you don't it goes through both slits. Observation, or knowledge of its identity, restricts which versions you interact with. Trippy and bewildering, but that is my current understanding.  

And how can one ever unite completely with one's higher self if it exists in the future?

Because time (the exploration of finity) is just a circle (the beginning and ending are the same), and where you fall on that circle is just a matter of what you identify with. So when your identification expands to encompass that particular state of development, you are then 'one' with it (or perhaps you have become identified with infinity itself -- the whole circle rather than just a portion of it).