Admittedly, the following essay is speculative. However, it represents a sincere attempt to make sense of our larger reality to the best of my capacity, as of the time writing this essay. At the very least, the essay offers some interesting food for thought.
In her work “Warped Passages”, the physicist Lisa Randall defines a dimension as a passage, a new direction. The following “two dimensional analogy” is not mine. Credit belongs to Edwin A. Abbott (1838-1926) who wrote it into a novel called, "Flatland". It was a work of genius that woke up many intellectuals to the implications of dimensionality.
We live in a universe that has three dimensions of space. Our three dimensions are length, width and height. Had our universe been a two dimensional universe, it would have been flat, containing only length and width. Hence, the name for the fictional universe called, “Flatland”.
A two dimensional creature living in the two dimensional universe of Flatland observes as a three dimensional ball crosses the flat plane of his universe. As the ball moves through, what does this two dimensional creature see? He sees a series of separate discs moving through his universe. In three dimensional space a ball is a single unit. However, in two dimensional space the same event translates into a vision of a series of flat discs.
In its own way, this is a commentary on the state of our own perception. We are biologically wired to see within the limits of three dimensions of space. If an entity existing in four or five dimensional space were to pass in front of our eyes, it would be perceived as fragmented. Perhaps limiting the dimensionality of a creature’s perception is part of the secret for providing that creature with a diversified universe. What's whole in a higher dimensional perception appears fragmented in a lower dimensional perception.
This might also be part of the secret of spiritual realms. These realms don’t necessarily have to exist in a different universe. They simply can be the way creatures wired to perceive more dimensions than we do experience the very same universe. Therefore, what some of what we experience as fragmented, they perceive as whole. So for example a prophet in deep meditation might isolate his or her soul from physicality to the level where s/he might perceive past, present and future as a singular whole, seeing the future with the same ease that s/he sees the present. By contrast, in his or her normative consciousness the past, present and future are experienced in distinct fragments.
A Kabbalah teacher of mine uses this notion to demonstrate how sometimes realities that seem at odds or even contradictory to the human experience, can be in perfect harmony or even a unified oneness in a spiritual realm that has more dimensions to hold it together. For example, he explained the particle/wave paradox of light using this notion.
The doorway to the area of physics known as Quantum Mechanics was opened by experiments that produced mixed messages about the nature of light. In certain experiments light behaved like a steam of particles, called photons. In other experiments, light behaved like a wave. Physicists were confused, “Is light particles or waves?”
My teacher taught me based on the teachings of Kabbalah that light is both waves and particles. Both expressions of light are simultaneously true and co-exist as one seamless entity in a higher reality. If light were seen from the vantage point of its true realm (not from where we're seeing it) it would look like a singular reality. It only manifests separately as particles and waves because human perception can only process in limited dimensions. As a result light fragments in our realm, splitting up an item that is one in a higher dimensional reality.
Following this logic consistently to one of its possible inferences, it seems that a what makes one realm higher than the next might merely be the amount of dimensions that its creatures can perceive in. So literally the perceptions of its creatures create the realm. Creatures capable of perceiving in more dimensions are just by their own perception living in a higher spiritual realm than creatures who perceive in fewer dimensions.
Our Creator is infinite in most absolute sense. He creates and removes dimensions to differentiate realms. He exists as if infinitely dimensional.