I am developing this theory for a fanfic, and I want to know if it actually makes sense, both by itself and in relation to CT canon.
I must note that it is full of bad science.
Spekkio says that the universe is composed of four elements: sky, fire, water, and dark. Of course this is rather different to most other element systems in fiction and lore which often include "earth" and "air". One could see the more common element system (fire, earth, water, air) as metaphorical to plasma, solid, liquid, and gas-the four states of matter. There is the matter of the Chinese system that uses "wood" and "metal" in place of "earth" and uses "earth" in place of a combined element, but I won't get into that.
So the way I am interpreting Spekkio is that sky, fire, water, and dark are metaphorical for deeper fundamentals of the universe.
Sky- Sky spells that we see Crono cast involve lightning, light, and even "life"(though the character being revived is likely not actually dead but just knocked out). I would take "sky" or "heaven" to mean energy. Energy is the currency of the universe and is present in the flow of elections and photons.
Water-This is very tricky. Water can be casted as is, or as ice. Water also can be used for healing since hey, much of the body is water and water is fundamental to life as we know it (and Robo for some reason, because he can be healed too but okay its just the game). Water does not mean much to the universe as a whole, yet water does have a lot of interesting properties. Water is the combination of two elements, which alone are gasses, water dissolves a lot of substances which become suspended within it, water molecules also adhere to each other very well. I would say that water represents some kind of force of cohesion, or even stability.
Fire-Fire is much more straightforward in CT, it's well, fire. Fire is combustion, and the same forces that make fire possible are also responsible for even some biological processes. Things like fire, or at least reminiscent of fire exist in outer space as things like supernova, stars, and solar flares. I would relate fire to thinks like transmutation, change, energy, radiation, heat, etc. Fire perhaps could be radiation(such as thermal energy) or instability, which nicely contrasts with water. However there is a lot of overlap here with sky.
Dark-This is said to be a combination of the three elements above, or is it? If it is, then it would not be an element. It could however, be a shadow of these elements? What would support that case if the spell names accurately tell what the spell does, would be the Dark Matter spell. The other dark spell names include Black Hole and Dark Mist. Black hole seems actually look like something sucking others into somewhere else. I am somewhat tempted to call "dark", "entropy" or even "gravity", some kind of force in the universe that in a way is the "pull" away from energy that us also fundamental to it? I am not sure but at least I vaguely seem to know what I am looking for.
Still this is very tentative and probably needs a lot of bad comic book science to work. Something that confounds me is that Marle seems to learn slow and haste, which are related to time. Maybe this could be handwaved to actually speed and slow metabolic processes. Or maybe Marle picked up a few things from going through gates a lot.
Which also brings me to time. Time could be the combination of all elements? Maybe time and space are made from all the elements. The happy "coincidence" that the CT party contains element users of all four types could be some kind of metaphor of unity/working together.
The sprites of Crono and Frog casting show them to be releasing a force within themselves. Marle looks like she is concentrating or praying. Lucca looks like she is actually chanting something when she is casting. Magus's casting animation is very different-he makes complex gestures and does not float as he casts. I get the impression that Crono, Marle, Lucca, and Frog are channeling their element, acting like a conduit to it and releasing it. Magus on the other hand is a trained mage, so he knows how to wield magic rather than just release it, this gives him more variety in casting, hence how he can cast spells not of his element and do things like fly, levitate, turn people into anthropomorphic frogs, and summon Lavos.
In D&D terms the other party members are like sorcerers and Magus is a wizard. Another way to put it is that it's like shouting vs. singing. However it seems that perhaps maybe from Spekkio's power that Crono, Lucca, Marle, and Frog quickly learn to refine their magic to do things like healing and revive members, or it could be born from the fact they are learning by fighting.
I think that it is possible for someone to cast beyond their element, but it takes a lot of experience and knowledge to do so. After all, the elements of the universe do not exist in isolation but fundamentally require each other to exist.
Although the terms sky, water, fire, and dark are mostly metaphorical, when such forces of the universe are harnessed via magic, in their rawer forms do appear as their literal names because they are being channeled through the planet's power, hence having a relationship with the Dragonian elements of CC. The natural phenomena themselves also contain that element of the universe more than others.
So what do you think?