Though not completely associated with spirit, it was still believed to carry the life essense that made the containment of spirit within flesh possible. It was almost as if we were seen as bottles of life, and the water inside was living, whereas the bottle was merely a bottle.
These days, we are more likely to see it as some elaborate, sensory-programmed wet-suit; a virtual reality robot in which we live, like a living bit of software inside of an organic device, grown to general, life-support specifications.
(A marvelously flexible and versatile bottle- but just a bottle none-the-less.)
I personally have a different take on the matter.
I see this as being an enmeshment of frequencies, where entire planes of existance slip into and out of existance, and interact with each other in the same space- interpenetrating each other in a kind of suspension, where some elements are literally cheek by jowl with each other, yet never directly interact- even as they both are affected profoundly by other substances that are more solvent, and interpenetrate both.
These substances ebb and flow- and
are changed as some combine; others
are merely carried, afloat and distinct
from each other. Imagine a massive
aquarium, where oil, water, alcohol
and ether are all combined. The oil
and water never truly mix, even when
agitated together. The alcohol
penetrates the water, and the ether
penetrates all three.