When I saw this I thought this would be an Ars Magica thread which has a specific skill CALLED magic theory. This skill is the uberskill when dealing with magic.
Magic in Ars works on the basis of pre-newtonian phsyics and pre-coppernican cosmology.
magic has 10 froms (from fire to animals, plants or magic iteself) and 5 techniques (creation-destruction, change without moving, motion without change and perception).
There are levels of matter Earth, water, air and finally fire then into the celestial realms such as the lunar sphere and the realm of fixed stars. Energy is drawn from ambient energies in the universe.
A fireball is only a fireball because the whim of the caster wishes it so, things normally take the form determined for them by god and therefore doing things contra to the natural order become harder.
A