Science is a way of talking about the universe in words that bind it to a common reality. Magic is a method of talking to the universe in words that it cannot ignore. The two are rarely compatible.
Neil Gaiman The Books of Magic
Magic is the art and science of causing change to occur in conformity with will. This change can occur 1) in the outer, manifest world; 2) in the magician's consciousness; and 3) most often in both, for changing one often changes the other. Magical change occurs in a way that is not currently understood by modern science because it works through the Unmanifest — through subtle manipulations of the invisible, spiritual realms. However, the workings of magic are subject to natural law. The effects of magic are sometimes clearly visible in the physical world and other times they are only apparent on a personal, spiritual level. The workings of magic are not limited by the constraints of time and space.
Chic Cicero and Sandra Tabatha Cicero The Essential Golden Dawn : An Introduction to High Magic
The Laws of Magic are the rules, power sources, expectations, philosophies, etc., that develop out of Functional Magic, or which are codified in a Magical Tradition. They define how magic works in your setting.
There's a few things you need to consider in regards to the Laws of Magic and their impact on your setting.
- Do you want magic to be mysterious and ephemeral, or well-defined and reliable?
- Is magic exceedingly rare, or surprisingly common?
- To what extent does Ontological Inertia exist?
- Is magic overpowering, or just another factor?
- Is it instinctive to resist, or does that take special circumstances or training?
- Is resistance voluntary or invariable (that is, can you deliberately not resist a spell)?
- Can you counterspell?
- Is it instinctive to resist, or does that take special circumstances or training?
- What is the source of magic in your setting?
- Is there but one style of magic, or do numerous Magical Traditions exist?
There is also the possibility of this term being used to refer to laws governing magic within the "wizarding community" (if such exists) and controlling what magic may and may not be performed. For benefit of values dissonance, this may not necessarily follow the line between "good" and "evil" magic anymore than mundane law can serve as a guide to morality.
Traditional "Laws of Magic"
These are some of the "laws" that real-world occult traditions have applied to the working of magic. They can be contentious and do not exist in all traditions, and this is an indicative rather than a definitive list:
- The Law of Contagion: Once together, always together or The part of the thing is the whole of the thing: A part of something - like one of someone's possessions or a part of their body - can be used to work magic on it over a distance as though it were physically present. The more intimate the connection the better the link works so a discarded cigarette packet is little use, whilst a favourite shirt or piece of jewelry is better and part of someone is ideal1.
- The Law of Sympathy: Like attracts like or The image is the thing: Where a contagion isn't possible an image of the target may be used instead. The better the image, the better the link - and even better if the target has personally endorsed the image. Signed photos are really good for this. Combining sympathy and contagion is the basis of Poppet Magic.
- The Law of Correspondence: Things look like what they are or as above, so below: This is the basis of astrological magic (that things correspond with their astrological profile) and can also be used to identify useful herbs and suchlike (if it looks right, or has the same astrological profile as your target, it probably helps). Something similar lies behind the (discredited) theology of the Doctrine of Signatures. It's a toss-up as to whether the use of a target's name in a working is Correspondence or Sympathy - depends who you ask.
- The Law of Consent: No injury is done to the willing or this works a lot easier with your co-operation: Depending on who you ask, this is either about the idea that magic is said to have difficulty effecting those who do not believe in it and/or about the idea that it is possible to consciously resist magic and it is far easier to operate a working upon someone who consents to be targeted than someone who doesn't. The concept of the humbug is said to take advantage of this.
- Equivalent Exchange: Everything has a price: Magic conserves a given level of value (although one or both "parties" may have different ideas of how something is valued) and a given effect must be paid for with something of at least equal worth. Part of the fun of magic where this applies is making absolutely sure you understand what you are paying before you seal the deal. This also tends to lead to magic that takes the path of least resistance, moving stuff about rather than creating it and what have you. Where the price is far more than the benefit, you're probably entering monkey's paw territory.
- Reciprocity (aka. "The Law of Triples"): Whatever you do by magic, for good or ill will be repaid to you threefold: Based on the idea that the universe is somehow "karmic" and rewards or punishes the use of magic. Fervently believed by many people but mostly nothing more than wishful thinking by those who think that there is a difference between "white" and "black" magic2. However, particularly when dealing with things like shamanistic practice, maleficium and other "hostile" magics will put you into contact with the sort of spirits that enjoy that sort of thing, meaning they can find you and effect you much more easily and they are rarely the sort of spirits you want finding you and effecting you even without the encouragement of a hostile worker.
- Reversal: Whatever magic does, magic can undo: Somewhat controversial, the idea that anything created by magic can be dispelled or otherwise undone by magic without needing to be physically destroyed.
- Distortion: Magic changes nothing … permanently: Even more controversial than the "Law" of Reversal, the idea that magic works by bending the universe out of shape but does not actually change it - sooner or later the world will snap back into its original shape. This is a good mechanism for causing no ontological inertia and explosive breakage of magical phenomena but does not fit with everyone's experience of magic.
- The Law of Balance: In the end, everything balances out: Very much related to the laws of equivalent exchange and reciprocity, this idea suggests that magic cannot create or destroy anything, but must move it from place to place (or time to time) - so good fortune now must be repaid by bad fortune later, restoring life to someone means taking it from someone else … that sort of thing. Again, not fully attested to by any magical tradition but popular in various mythiea regardless. Known to modern cynics as "the Marxist theory of magic".
- Backlash: If you don't know where it's pointed, it's pointed at you: Some traditions hold that once a magical working is started - especially a working of the harmful variety - it needs to go somewhere. There are likely to be ways and means of safely "earthing" an aborted working (if you can get them right and have the chance to do so), but more worrying still are those workings which miss their target and/or snap back because they are resisted or reflected. Death spells are especially notorious for rebounding on the caster if they fail to kill the target3. Such traditions may well develop ways of passing the damage onto someone else - especially the clients of those casters performing this kind of sending for hire or reward. This is the sort of context in which you need to be absolutely sure of your targeting data before you start your attack.
Where the laws of magic are studied, codified and researched in a (pseudo)scientific manner "in universe"4, this is generally called thaumatology. Whether this exists - indeed whether it is even possible - will depend a lot on the meta-game rules governing the setting.
Sources and Types of Magic
Here's a list of some possible interpretations or sources of magic, as suggested by the folks over at the TV Tropes Wiki:
- Inherent Gift: Only those born of a certain blood have the gift of magic. See Witch Species.
- Theurgy: where the magic is done entirely by spirits and gods with whom the caster makes deals.
- Rule Magic: where some underlying magical rule system is applied, as in manipulation by True Name or sympathetic symbolism.
- Force Magic: Practitioners of magic tap into and control or weave together one or more magical forces.
- Device Magic: Magic performed with some form of mystical device or relic.
- Wild Magic: Magic that does what it wants, or just happens beyond control. In other words, non-functional magic.
- Word of Power: Individual words containing the raw essence of magic.
That list does a great job of categorizing magic as it's depicted in modern media. In some settings, magic is a thing you learn, a topic you study. In others, it just comes naturally to those with a certain talent or bloodline. And in some, magic is just green rocks or handwavium. There is, of course, some room for overlap. A given setting may feature more than one type of magic, and there's even the possibility that each type could have it's own laws of magic.
-mancy, and Magical Tradition provide ideas on "real-world" magical systems that can influence how magic works in your game.
Schools of Magic is a useful idea that may help grant some structure to your Laws of Magic.
Thaumatology - where laws of magic exist, sooner or later academics will study them.
Vancian Magic is an example of a fiction Magical Tradition.
Game and Story Use
- Defined laws of magic empower magic to serve as a reliable problem-solving tool, without them magic is very inconsistent and probably subject to the whims of the plot. In other words, the Laws of Magic can spell the difference (at least in perception) between a fair challenge and railroading.
- Role-playing games pretty much need functioning laws of magic (if they feature magic at all). Some really rules-lite Indy RPGs might be able to get away with nothing but plot magic and improvisation, but it's hard to sustain that for more than a short-shot. Especially if the PCs are themselves spell-casters or occult experts, the players need to understand magic enough to defend against it, prepare for it, and make the most of it. If it remains as nebulous as green rocks or the green lantern ring, that's really hard to do. See Phlebotinum for further discussion of this topic.
- In a setting where magic is dangerous or wild, one can justify non-functional magic and/or hiding the laws of magic from the player characters. For example, in a Call of Cthulhu campaign, you could certainly get away with concealing the limits of magic from the players unless they pay precious sanity points to figure it out.
- Of course, ill-defined and nebulous laws of magic help keep magic feeling mysterious, which is why one-shots and games without PC spellcasters can sometimes get away with the handwave
- The Law of Contagion works much better with parts of the target's body - including bodily fluids. Spitting on a wizard suddenly becomes a bad idea on a whole new level.
- There is a reason that most cultures regard cursing your parents so harshly - it's really, really easy to do because you are quite capable of serving as a channel in your own right being an exemplar of both sympathy (being made in their image) and contagion (being made from their bodies). The link is so open that even a metaphorical curse can be transformed into a literal one without meaning to. Of course, those most likely to curse their parents are probably the ones with the weakest connection to them, but still…
- …and yes, this does mean that you can cast sendings against people by using their relatives as a kind of poppet.
- The law of consent may be invoked in various forms of conditional magic, including death curses "kill me and my curse will fall upon you" and ward magic - "if you cross this line your ears will fall off". By performing the act against which they have been warned, the violator effectively assents to receive the specified penalty - which may eliminate or reduce their ability to resist it.