So, humanity starts off in the 3rd dimension. Which is the world as we know it, or rather, as we knew it. The best way I heard of making sense of it is that this is the way that you get things to happen in 3D:

spirit -> thought -> emotion -> effort-> manifestation

So, to contrast it, let's move on to 4D, the 4th dimension, or 4th density. Here the sequence that leads to manifestation looks like this:

spirit -> thought -> emotion -> manifestation


OK, on to 5D, the 5th dimension. What happens there is:

spirit -> thought -> manifestation

We could go on the same way to 6D:

spirit -> manifestation

7D would be that you no longer need the manifestation even. Pure spirit. Or, if you want to look at it materialistically, it could be if you had uploaded yourself to a computer, and you were perfectly happy with simulated experiences, rather than "real" ones. And anything you might ever want is instantly available to you. All at the same time, if you want. You can be anybody you want. So maybe you move on to a different kind of meta-perspective that no longer seeks human kinds of experiences.

http://www.futurehi.net/archives/000086.html