Magic exists on Resolution, and can be utilized by mages or certain animals possessing magical ability. Not just anyone can make use of magic; you were either born with the ability, or have received biomodification to grant you magical ability later in life. Either way, the use of magic is a strictly biological affair; while technological dampening and dissipation of magical effects has been achieved to some extent (more on that below), neither robotic beings nor technological devices have yet been created which can induce new magical effects.
In rare cases, people are born with the natural aptitude for magic. This tends to be more (or less) frequent in some regions and populations than in others, suggesting that the mutation allowing magical aptitude is either passed through genetic lines, induced by environmental factors, or both. While some of these lucky few show obvious magical abilities spontaneously at an early age, others develop aptitude and skill slowly over a lifetime. Some mages who were not lucky enough to be born with their abilities have been biomodified with a special gland that grants them magical ability. Still others may have been born with their gifts, but have had them enhanced through additional biomodification. Regardless of the source of a person or animal’s magical aptitude, the function is the same.
The degree of magical aptitude has an effect on both the skill and power of spell casting. The higher the mage’s aptitude, the more likely the success of spell casting, and the more powerful the effect. While magical energy is usually invisible to non-mages until cast as a spell, mages with very strong abilities will begin to develop a glowing aura which is visible to mage and non-mage alike. This indication of unmistakable power can inspire great awe and respect, or great fear and mistrust depending on the disposition of the observer. To conceal such symptoms of great magical power is difficult at best, even with concerted effort and practice.
While scientific study of magical phenomena has been frustratingly slow and limited, it has been established through the accounts and personal experience of mages that “spell casting” is effectively the manipulation and focusing of ambient magical energy through a series of complex and delicate movements (and exactly why these movements elicit particular effects is unknown). At any rate, mages universally report that they can somehow “feel” the magical energy around them (most describe it as being similar to the sensation of moving through a thin fluid), and they are able to manipulate this energy to produce magical effects (to “cast spells”). The movements are immensely complex and delicate, and are complicated further by the fact the they will be slightly different for each spell caster; as all casters are physically different in shape and size, the movements must be tuned to the individual caster through careful practice, so a theoretical knowledge of a spell is not enough to cast it. Imperfect spell casting movements can at best have lesser or no effect, and at worst lead to entirely unexpected and usually undesirable results.
While extremely patient and intelligent mages have been known to modify or, more rarely, invent new spells, it is far more common for spells to be taught in some fashion. A well-connected, socially-savvy, or financially persuasive mage may be able to convince a more experienced mage to pass on his or her knowledge, though such knowledge is often well-guarded. Additionally, more empirical mages have, over the years, developed a vast array of arcane symbols into a sort of language which broadly and generally describes the required movements to cast their spells. While recorded instruction of this sort is unambiguous and usable by anyone familiar with the language, the personalized nature of spell casting requires a great deal of practice beyond a simple reading of instructions before the student will be able to successfully cast the spell. Neither personal magical instruction nor written spell tomes are commonly available; a prospective student will need to spend many diligent years in pursuit of instruction before amassing any quantity of spells.
The majority of spell casting is performed by way of the complex movements described above. Unfortunately this requires at least a small amount of time to perform the movements (proportional to complexity and inversely proportional to skill), as well as the ability to physically move (so a bound or otherwise physically incapacitated caster will find his or herself out of luck). However, it is in fact possible to cast a spell nearly instantaneously and with very little movement if one is willing to pay the price for such ability: In order for a mage to cast such instant effects, the mage must undertake the daunting and agonizing process of inscribing a series of arcane glyphs into his or her own flesh. The deep, distinctive, and permanent scars seem to somehow substitute for the otherwise-required movements. The scarred symbols are similar in appearance to written spell symbols, but just as with casting movements, must be customized by the caster. The process of inscribing a spell into the flesh is a delicate and painful ritual. The mage must be extremely familiar with the spell to be inscribed, and must inscribe the spell into his own flesh; only the caster can know exactly the shape the symbols must take for his own use. Additionally, no pain medication or other action to mitigate the pain can be used as it interferes with the accurate inscription of the spell. Such spell inscriptions are permanent as they cannot be removed without risking dangerous magical backfires. More complex spells take up more area on the caster’s flesh, and the maximum number of spells a caster can inscribe is limited by available free space. Multiple related spells take cumulatively less space as portions of the symbology can be re-used. In almost all cases, the inscription of a spell will be an event that involves a great deal of planning, physical/mental preparation, solitude, and physical/mental recovery.
While spell casting requires biological aptitude, some headway has been made into electro-mechanical dissipation of magical effects. Such devices typically involve certain rare metals, spun into strands, twisted into a great number of plant-root-like branches, and arranged into a sort of web that covers most or all of the person (or object) requiring protection. This web is powered with an electrical current which is modulated by an oscillating piezoelectric crystal. As long as the web is in contact with the ground (or a body of water), incoming spells will to varying degrees be captured and dissipated. The effectiveness of this system is dependent upon a number of factors, including the power and complexity of the spell, the power provided to the system, and the quality and quantity of materials used.
See the Magic section of the Character Creation Checklist for GURPS rules details relevant to the setting.