Many philosophical systems – and thus, many fictional universes – divide the universe into matter and spirit. Matter, of course, is the stuff physical objects are made out of. You can see it, and you can touch it. Spirit, however, is different. In particular, there is little agreement as to what spirit is.
Spirit, the word, is derived from the Latin spiritus – breath. The word is linked to the concept through a metaphor: like breath, you can’t see spirit, but you know it’s there. Frequently, spirit is connected to the mind, with spirit being the source of thoughts and ideas. In Plato’s philosophy, I’m given to understand that there was an resolved problem in how the purely mental Forms could actually manifest and interact with the physical universe.
This brings us to another question: do minds have location? Are they in a specific place, like the pituitary glans inside our brains? If they were, what would happen when we die? Would our souls be trapped, or would they fly away, to where ever or what ever it is that they are called to? And if minds do have location, it’s still not clear how the two substances of the world actually interact with each other.
So much for philosophy; now, let us continue to fiction. Many works, such as Bleach and Exalted, postulate that spirits can inhabit mundane reality, unseen and untouched by all but a few. Here, spirit seems to act as nothing more than a subtle form of matter, even through the implications of philosophical dualism. Interestingly, however, both of these works also postulate the existence of several spirit worlds, where only spirits reside, and the subtle matter is the only matter that exists. I feel that it is noteworthy that both of these works deal a lot with the spirits of the dead.
Ghosts can be considered a bit of a special case. Unlike other kinds of spirits, ghosts use to be a part of mundane existence. Having died, they can no longer continue to interact with the world as they used to, and are, at least implicitly, expected to move on to another world, a world that they now belong in. This world would naturally be made of the same substance that ghosts are.
I began this essay to figure out what it was that bothered me about how Bleach and Exalted dealt with the problem of matter-spirit dualism. I now understand what the problem is: despite the fact that both works want death to have meaning, and as such, treat being a ghost as being substantially different from being alive, they both treat the afterlife as little more than an interesting place to have a sword fight.
There’s no thought given as to why every world has a spiritual component, but only mundane existence has a material one. The seeming primacy of spirit goes unexplained, and the significance of matter goes unexplored. Both works simply ask us to accept that the world as presented, without regards to how the metaphysics link to the work’s themes.
It’s not like I’m saying it was a bad call; sword fights were what people came for, after all. I think I just want to put a bit more thought into my settings than the above. In Occulted, for example, I decided that subtle matter was the source of the preternatural powers; the part of the world you’re unaware of until you are. My other projects, however, have other themes, and they need their own relationships with spirit and matter.