Magic is a principle of the universe which is not fully understood, yet it is used by Magicians (who study it scientifically) and Priests (who accept it by faith).
Magic is "divided" into the Greater Path and the the Lesser Path, but this is only imaginary; only few realize that there is no Greater or Lesser forms, only Magic.
The Greater Path is supposed to be the better path; the noble path, and was not known to Midkemians (Apart from Macros the Black) until the Riftwar. It is followed by The Assembly upon Kelewan.
There are some, notably Nakor the Blue Rider, who disdain the notion of magic, insisting there are only tricks, and that anyone can learn magic.