Magic, and the working thereof, is governed by a number of rules. These rules limit what Wizards are able to do, often by placing unwanted consequences on their actions. Other Laws form the fundamental basis for magic in general or specific magical disciplines.
- This article draws heavily upon Maggie Finson's Fey: Learning Curve, which is the foundational work on Magic within the Whateleyverse.
Law One, also called Law of Balance or Rule of Reaction, states that for every action, no matter how small or unintentional, there is always a reaction of equal or greater intensity. This means magic will have effects in addition to the obvious. These effects could be unwanted and possibly dangerous to the Wizard or to others.
Note that this is contrary to Taoist theory, which states that the closer one comes to acting in accordance with the Tao, the fewer unwanted side effects occur. See the traditional teaching story about the butcher, his knife, and the Emperor.
The Law of DefinitionEdit
The Law of Definition states that the Universe Is What We Say It is. A Wizard defines their own surroundings with their perceptions and influence on the things and people around us. It is considered the most important Law by some and that all other laws are aspects of the great whole of this law.
This may (or may not) be related to Devisors, who seem to operate with a variant of this Law.
The Law of DominionEdit
The Law of Dominion states that when a being makes a definition that a place or circumstance is their Place of Power, then they have near ultimate power in that place, until they are displaced from there. A Dominion must have set boundaries and the Master's power extends only to those borders and no further. This is similar to a spirit’s Hallow.
The Law of CyclicalityEdit
The Law of Cyclicality states that things work in cycles. They begin, they work their way to a mid-point, then they decline, and finally end. It also means that Magic is an exception to the normal course of events in the world, a disruption of the natural order. As such, it causes disruptions in the course of things around it, which create smaller disruptions further away and so on, like a pebble thrown in a pool causing ripples that radiate out, and fade away. When a cycle has begun and reaches its point of no return, then it will complete itself, no matter what anyone does.
This Law is related to Law One and together they mean that a spell isn’t finished until all of its repercussions end.
The Law of NemesisEdit
The Law of Nemesis states that when someone or something begins to advance a course of action, the Universe will bring up something or someone to oppose it. That person, being or thing is the best suited for the task, and has the best chance of succeeding. The Law means that nothing at all comes into being unopposed and that there is always an equal force to balance it.
Again, this is contrary to Taoist teaching, which says that actions taken in full accordance with the Tao don't stir up reactions. This is, of course, very difficult to accomplish.
The Law of PactingEdit
The Law of Pacting states that when a magical pact is made, it binds those who made it into honoring the agreement. Breaking a pact will have terrible repercussions for the one who does so. This means that breaking a pact can have dire consequences, especially if one or more of the parties involved is supernatural.
The Law of SimilarityEdit
The Law of Similarity states that things that are alike affect each other. This Law forms the basis of Sympathetic Magic and means that by making a change in one thing, a second object, connected by Similarity, will change as well.
Similarity is a matter of symbolism and intent as interpreted within a particular Tradition; it need not have any physical basis. Also, things that are similar in one tradition need not be similar in another. For example, a proper application within an appropriate Tradition could result in unlocking a computer firewall by unlocking an old-fashioned key lock that's based on wards (rather than more modern tumbler locks).
The Law of ContagionEdit
The Law of Contagion states that once two things are joined they are always linked, as summed up in the phrase once joined, always linked. This Law means that objects like a lock of hair or nail clippings can can be used as a magical link to whatever or whoever the sample was took from.
All Wizards try to keep this Law in mind during their daily lives because of the potentially deadly effects if it was used against them. As such they will be carefully not to leave hair or nail clipping where enemies could get them. Some even go as far as to constantly use spells that vaporize any such elements as they leave their bodies. 
The Rule of IntentEdit
The Rule of Intent states that what a Wizard intends, not what they say they intend, affects a magical working. Emotions like Anger, Greed or Lust can and will contaminate what a Wizard believes is an innocent working. It also means that trying to cheat frequently won't work: the intent is what governs the result.
The Law of PrecedentEdit
The Law of Precedent states that what happened before, will happen again. This means that the more a working has been done in the past, the better a chance that it will work in the future.
It does not mean that it will be easier, only that it is more likely to work as intended. Also, this applies to a Tradition as a whole, not just to the individual workings in it.
The Rule of the Essential FlawEdit
The Rule of the Essential Flaw states that nothing is perfect. It means that there is a weak spot in everything and that nothing anyone does is unbreakable. However the weak spot can be hard to find, especially in well constructed spells.
This is a consequence of the notion that everything is connected. To make a completely flawless work would thus require taking the entire multiverse into account: an obvious impossibility.
The Law of ThreesEdit
The Law of Threes states that things don’t come alone. Events, and even people will bring others similar to them at least twice. An example would be deaths coming in threes, as shown in many old stories.
The Rule of ThreeEdit
The Rule of Three states that in mystical conflicts one side has three chances to attack the other before the Law of Balance takes full effect and makes further attacks a supremely bad idea until balance is restored. This partial exception to the Law of Balance is what allows meaningful mystic conflicts in the first place. 
The Rule of Three also states that in certain situations good works or conversely evil deeds can reflect on the originator threefold. This is limited by the Rule of Intent so that good works done only with the intention of reaping the threefold effect will not benefit.
The Law of Three only appears to be a part of some traditions, and not others. As such, it may be a consequence of the Law of Definition as applied to specific Traditions. That doesn't mean that a mage working in a tradition that includes this Law can ignore it! The Law of Precedence applies to a Tradition as a whole as well as to individual workings within it.
The Law of NamesEdit
The Law of Names states that having something's True Name grants the holder power over that thing. This Law causes Wizards to carefully guard their True Names, lest someone use them to exert control over them.
Exactly what this means seems to be a matter of the specific magical Tradition. In some Traditions a True Name seems to be an otherwise unrelated symbol, in others it's more of a metaphor for a fundamental understanding of the nature of the object in question.