Magical Theory

''Since Pottercraft has no Magical Theory class, this page is instead dedicated to a discussion on enchantment. If you would like your character to attend a seminar on Magical Theory or any other advanced topic not currently covered in the Hogwarts curriculum, please contact the worldbuilding team.''

What is Enchantment?
Enchantment is the craft of imbuing spells into a runic array, to be placed on an object or area. It is nearly always the case that when an object or area is described as cursed, it is under the effect of an enchantment. No differentiation will be made between benevolent and malevolent enchantment in this text.

Enchantment holds several advantages over spells or transfigurations, among which are the following:
 * Permanency. Wand-cast spells wear off over time. Enchantments wear off when power runs out. If a viable power source is included, enchantments can outlive the enchanter by a large margin. (Note that some arrays are not designed to last beyond one use.)
 * Repeatability. Wand-cast spells typically take effect, or begin effect, at time of casting--once. Enchantments are frequently (though not always) designed to reset.
 * Complexity. It's much more practical for an enchanter to utilise complex conditions for triggering an enchantment, determining the effects, and targeting the effects, than it is for a wand-using spellcaster. (Not all enchantments are complex.)
 * Portability. An enchanted object can provide utility to wix who have never even met the enchanter, even hundreds of miles from its creation. Wand-based spellcasting only affects those in range of the spellcaster. (Not all enchantments are cast onto portable objects. Some are used to protect areas or structures, usually by carving the runes or entire array into stone or the ground.)

Caveats

 * Some spells are amenable to being linked to other spells when cast with a wand, so not all use of linked spells is indicative of enchantment.


 * The simplest runic array contains a single imbued rune, so enchantment does not necessarily entail multiple spells, either (though in practice it nearly always does). Neither does enchantment require more than one of triggers, targeting, and effects (though in practice nearly all enchantment uses all three)--nor is it impossible for a spell nor wand-cast linked spell system to have all three.


 * The runes used need not have any special significance or particular shape, so long as they are matched one-to-one with specific aspects of the enchantment, consistently. (However, the United Kingdom Ministry of Magic require enchanters to use Elder Futhark or Ogham, with conventional use of symbolism, in patent applications and--in the case of mass production--health and safety inspections, or else to provide a clear translation to their officials.)

Anatomy of an Enchantment
Every rune in the runic array of an enchantment corresponds to a specific aspect of the enchantment. There are three broad categories of aspect: Once a specific rune has been imbued with a specific aspect, all uses of that rune in that runic array must correspond to that same aspect. Likewise, though with less severe consequences of failure, all uses of a given aspect must correspond to the same rune. (Combining runic arrays is thus highly imprudent.)
 * Triggering conditions
 * Targeting rules
 * Effect descriptions

Triggering Conditions
A beginning student may be tempted to think, from the examples given below, that triggering conditions most often tend to involve existing utility spells like Cave. This is not the case for professional enchanters. Dijkstra's Trigger, for instance, is a common triggering condition in use and is as follows:"The path of least resistance between this and a chosen object category, person, or location--counting magical resistance as infinite or else according to a visualised heuristic--is less than a specified distance."Other examples of triggering conditions:
 * Someone is touching the object.
 * It is noon.
 * It is summer solstice.
 * The object has been submerged in water.
 * A category of person (e.g. an enemy) has crossed a boundary.

Targeting Rules
It is highly recommended that a distance scope be included, lest the enchanted object burn itself out by either checking or affecting those closest, those next-closest, etc. unto the entire world, or, much more frequently, until it runs out of power.

This may not be necessary if the targeting rules are connected with the triggering conditions, as they often are.

Examples of targeting rules:
 * Everyone in a one-meter radius.
 * Everyone touching the object.
 * Boys.
 * Anyone bleeding.

Effect Descriptions
Any wix not suffering from complete retrograde amnesia likely has an excellent database of reasonable enchantment effects. (If this describes you, please consult your grimoire and see a physician; not necessarily in that order.)

Two special categories of enchantment effects are worthy of note: reset/interval, and power draw. They are beyond the scope of this beginner's text.

Combining Runes In An Array
If you have more than one rune in your array, you're going to have to link them. There are three types of links: proximal, intercategory, and intracategory.

Proximal Links
"This rune is close to this other rune on the paper so I'm going to draw a line between them for structural integrity of the runic array." Meaningless, except that two runes with this link do not have either of the other two types of links between them. (Though other runes of the same two specific aspects may, elsewhere.)

Intercategory Links
This type of link is what tells an enchantment to take into account the trigger conditions for targeting, or the targeting conditions for effect scope, or indeed, in some particularly complicated enchantments, to focus in on the target of the last effect for future triggering. Magically strengthen the line between two runes whose aspects are of separate categories but which are otherwise related. (Do not magically strengthen lines willy-nilly when casting the net.)

Intracategory Links ("Uplinks")
Let's say you want your enchantment to trigger when someone is touching the object and it's solstice. Or you want it to trigger when someone is touching it except if it's solstice. These kinds of combinations are possible--but at a cost.

The only intracategory link that exists the wide world over (not exactly true; see sidebar) is a magical connection that produces the outcome of "everything except what is in both of the input runes", a connection which is represented with an up arrow (↑). It is, in fact, possible to use nested uplinks to produce the effect of the simple "and" or "or" or "not" operators which humans have invented in maths but not yet succeeded in implementing in magic. But it is a Merlin-cursed pain in the hindquarters, and it only grows more frustrating as the complexity of the enchantment increases, and the enchanter finds themselves using the same rune for the same aspect dozens or even hundreds of times simply to express its interactions with several other aspects. "Technically, there exists an equally frustrating one-operator-produces-all alternative, represented with a down arrow (↓), which means 'everything except what is in either or both of the input runes'. However, the spells for casting a runic array utilising downlinks are entirely incompatible with the spells for casting a runic array utilising uplinks, and very few enchanters of note in Anglo communities enchant using the technique, so it is not recommended that beginning enchanters familiarise themselves with this operator, unless they intend to work with goblins or ancient Egyptian curses or French people or something."There is a reason why almost anything which is not mass-produced to be used by many, many people is simply transfigured into useable sentience rather than enchanted--why so few people become enchanters--why, indeed, a number of promising young enchanters in recent decades have left the wizarding world to study Muggle programming instead--and this author lays the blame entirely at the feet of uplinks.