Way back before some of you were born the late Gary Gygax introduced us to something he got from Stephen R. Marsh, who in turn got it from Madame Blavatsky’s Theosophical Society. The premise is that what we know of as reality is actually a multivarious thing. What we think of as reality is just the physical plane, and that there are others besides it. For Dungeons and Dragons Gygax named it The Wheel, then later adopted it for Dangerous Journeys.
In the center is the physical, or Prime Material. Though they are most often represented as being outside the center the Ethereal (mental) and Astral (spiritual) planes are actually blended in with the Prime Material, though they remain in some sense separate.
Other planes include the Elemental, the Divine, and the Abyssal. For the most part the Elemental Planes are thought to correspond with Air, Earth, Fire, and Water, though you could think of them as being Gaseous, Solid, Plasma, and Liquid instead. In the case of the elements you may want to think of them as embodying the qualities of gas, solid, plasma, and liquid. So that an Earth Elemental could exhibit the qualities of Earth, even in the form of an elephant or, for that matter, a garden slug. A shark can be seen as having the nature of water, and so a water elemental.
At present our science sees only the Physical Plane, though there are times when the others seem to peep through. We think of thought as a physical phenomenon, but there are aspects of thought that don’t quite fit into what we call physicality. The same with feelings and understanding, which may have much in common with the spiritual (Astral) plane.
And then there are times when some things seem to arise from below, or come down from above.
Of course this all assumes that reality is a two dimensional circle. More likely it is three dimensional sphere, and that there are planes and the like out there on the horizontal instead of the vertical. Though assigning what is the vertical what the horizontal is most likely not possible from our vantage point. As far as I can tell our Solar System would appear to be tilted sort of slightly off the vertical where our galaxy is concerned, and that our galaxy is somewhat tilted. We ever get to and pass the boundary of the universe we may well find ourselves ascending or descending into and through a higher or lower plane.
I come up with stuff like this because I’ve learned we know nothing really, and that what is out there could make us cringe with the apparent impossibility. For remember that Infinity can have no limitations. That is Infinity’s limitation.