Magic can be tentatively divided into five types:
Intrinsic, Residual, Induced, Wizard (Including Sorcerery) and Witch
This is the Magic that derives from the Nature of the Universe.
It is the Intrinsic Magic which, for example, is responsable for the slowing down of light on the Discworld, but at the same time makes it possible to see light coming.
Intrinsic Magic is the equivalent of God, thinking.
A powerful force, which needs some background information.
Most Magic as used by wizards and witches is a simple channeling of the Intrinsic Magic of the world.
It can be stored in accumulators such as staffs, carpets, spells, and broomsticks and can be thought of as a slowly renewing resource, like geothermal energy.
It is subject to certain laws similar to those of the conservation of energy. A wizard can, for example, cause fires and apparations and coloured lights quit easily, because these require very little energy.
In the same way, a person may quite easily be turned into a frog by causing their brain to regrogram their own morphogenetic field.
The effect is temporary but embarrissing.
But a Wizard can rise vertically in the air only by locating a large solid object of similar weight in a high place that can be dislodged without much force, so that the descent of the object largely propels the rise of the Wizard.
No common magic is powerful enough to cause, for example, a pork pie to come into complete permanent excistance.
This would require quite a large amount of new energy to be created within the Universe.
As much energy, in fact, as would be necessary to create a one hundredthof a pig, one ten-thousandth of a baker, one hundredth-thousandth of a cleaver, several pounds of flower, saly and pepper to taste and a couple of hours of baking.
All this can, however, be easily achieved by a Sorcerer, who can channel raw creative force and may be thought of as the human equivalent of a white hole. He can create and destroy by a mere thought.
Only a few Sorcerers are left since they engaged in vast magical wars which left whole areas so lousy with Magic that the laws of cause and effect no longer apply.
An often neglected but very powerfull form, and available for use even by non practitioners. It is the Magic potential created in an object, or even a living creature, by usage and belief.
Take in its simplest form, Royalty. It needs but a royal marriage to turn a perfectly ordinairy girl, that no one would look at twice, into a Radient, Righ, Royal Princess and fashion icon.
Mirror Magic also comes into this category. Witchess belief that if they stand between two mirrors their personal power is multiplied by their reflections. This is clearly a folk superstition,
which happens to be true
Wizards are graduates from the Unseen University. Wizards can be divided into eight orders and eight grades. There is nothing to stop any one calling themselves a Wizard of the ninth grade
except the fact that if they meet a real Wizard they're likely to end up sitting sadly by the pond waiting for a short-sighted princess with a thing about the colour green.
Grades up to twenty-one have been reported, but this is considered to be just foreigners being excitable, and they impress most wizards as much as porcupine-sized epaulettes on the shoulders
of a shifty-eyed banana republic Generalissimo impress a battle hardened soldier.
Wizard Magic generally consists of illusion, a little weather-making, fireballs and the occasional darning of the Fabric of Reality.
Fundamental to its use is the Wizard's staff, usually about 6 feet long with the proverbial knob on the end. Daily rituals with the staff accumulate magiacl power which can be discharged very quickly at need, or stored in spell books and triggered by the syllables of the spell.
A Sorcerer however is the eight son of an eight son, and his father must be a Wizard.
Unlike wizardry, which, shorn of the coloured lights and fireballs, largely consists of persuading the Universe to do it your way,
Sorcery is the immensely power of the storybook Wizard - he can stop the sun, make the sea boil and all other things such Wizards feel they have to do
He is a channel through which Magic flows intto the Universe, and the human equivalent of a white hole.
A Sorcerer can only be beaten by another Sorcerer.
This belief held sway for hundreds of years until it was realized that this only applied where direct magical contest is involved
A half-brick wielded in a sock is otherwise perfect for the job
Unlike Wizards, Witches are solitary creatures. They enrol in no schools and have no formal system of regulation
Witches generally get together only rarely.
Contrary to salacious popular belief, there is no question of them doing anything whitout their clothes on. Most serious Witches are elderly and keep several layers of flannelette between themselves and the outside world at all times
Witches have infact a very strict and moral code.
Witches are trained by other witches, one on one, with one of the trainees taking over the area when here teacher either dies or quits the world in some way.
This means that over time an area may see a succession of witches of a roughly similar strain.
The basic unit of Witchcraft is the cottage, which may be inhabited by Witches for several centuries.
Another significant difference kies in the attitude to books. Most Witches can read and write but place no particulair value on books
Wizards whitout a library would just be fat men in pointy hats
Some of the aspects of Witchcraft are, headology (psychology), natural talent for herbal remedies and a bit of social work, psychic powers and research witchcraft
All Witches fulfil the usual daily functions expected of a rural Witch:
Midwifery, the laying out of the dead (and sitting up with them at night, possibly playing cards with the more unusual cases) and folk medicine.
There is no concept of white/black magic. There is simply magic, in whatever form, which may be used in whatever way the user decides.
Suggesting that there is any type of Magic that is intrinsically good or bad would make as much sense to a Wizard as suggesting that there is good and bad gravity.
(Of course, from a subjective point of view there are such things as good and bad gravity. The gravity which causes an aircraft to crash is obviously different from the gravity which stops everthing flying off into space)
The Discworld Companion
Terry Pratchett 1994/1995