On Magic, and its variants, in Fiction Part I

In any fictional work where something that is impossible in our world is made possible in that work must be explained by either advanced technology that uses hitherto unknown sources of energy, some set of magic rules, or both. Magic has a different basis in every canon, be it based on demonic pacts, allegiance to a deity, elemental control, a practical second set of physics, psychic ability, what have you. What magic can do and how it is done has an affect on that fictional world, and that is generally reflected in how similar the fictional world is to the real one, mostly because real world rules generally still apply, especially if not everyone has access to whatever magic there is. I shall demonstrate this with a handful of magic canons*.

One set of magical rules in a world where real physics also apply is the magic of the Dungeons and Dragons realm. I begin with this because these rules were carefully thought out for use in a role playing game, rather than simple explanation in a single work of fiction, and I feel as though it has the most "accurate" background description for multiple theoretical functionalities of magic. In D&D, there are a number of ways to access different forms of magic, which is divided into two types, arcane and divine.
Arcane magic is what might be considered in other canons as "alchemy," a manipulation of the rules of reality to achieve desired effects. It's basically a secondary set of physics, with it's use of verbal, somatic, and material components. Arcane magic is accessible to anyone who wishes to study it*. Arcane magic is the most frequently seen in other works of fiction. Wizards and sorcerers serve as both heroes and villains in many stories, and their particular magic generally obeys the same set of rules, and, whether inherent or learned, is often supplemented by study and the creation or acquisition of magic objects, including but not limited to rings, orbs, staffs, wands, scrolls, etc. For the purposes of this study, such magic will be hitherto referenced as secular magic, because of it's lack of a need of any sort of deity to function.
Within the same world, there is divine magic, where explanation of super-natural abilities comes from a deity. God given magic has the most power in the D&D realm, mostly to make another character class more fun/useful to play as, but divine magic is seen in other works of fiction in a smaller capacity. This particular form of magic works the same way with good or evil, one simply gets power from a benevolent god or an evil god or devil, depending on the religious or spiritual background of that particular story. This will continue to be referred to as divine magic, as the term is basically self-explanatory.
The magic of the druids in D&D is also called divine, but, ironically speaking, it's somewhat of a misnomer. The power of the druid comes from her connection and resultant influence over the forces of nature. Because of the connection between natural forces and man's earliest belief in any sort of deity, this makes sense, but in most canons there is a clear separation of the spirituality and magic of nature and the magic of religion. It's less refined, and generally corresponds with power over the classic elements of earth, air, water, and fire, control or at least empathy with plants and animals, and a measure of influence of the weather. This will be hitherto referenced as natural magic, for obvious reasons.
In D&D, many spells have a variant for each kind of magic. Example, a lightning bolt. A secular spell caster would use a material component in conjunction with an incantation and a flick of the wrist to alter reality in order to shoot lightning from his finger tips, a divine caster would call on his god to smite his enemy with a lightning bolt, and a natural caster would summon a storm cloud and create a natural lightning bolt. Each of these magic wielding characters is iconic in various other canons, but they are generally not seen in the same story because the difference in the sources of their abilities is confusing when combined. In a world where one can alter physics with incantations and materials, ignore physics by praying, or supplement physics by communing with nature is a little overwhelming. However, each of these different kinds of magic forms a ground from which we can decide how magic functions in almost any realm of fiction where magic is present.

Using each of these magic using types as a ground work, I will approach the use of magic in a range of fictional works and genres. Hopefully, this will shed some light on how we understand something that is supposedly the incarnation of the incomprihensible in our imagination.

*note spelling. While demonstrating my thoughts with magical cannons would be pretty awesome, it would be ineffective for a number of reasons, one of them being their unfortunate lack of existence.

*There are some to whom the ability to use arcane magic comes naturally, but the Sorcerer/Wizard differentiation is somewhat irrelevant to the topic at hand.