Magic is largely a result of biological functions, every person and even some animals are born with the ability to utilize varying amount of Mana. The ability to utilize mana to cause supernatural phenomenon is known as magic. Everything that possesses the ability to use magic radiates a small fraction of it’s power in an aura called a Sorcery Field. Some individuals can measure this to determine the source’s magical strength. Magitech sensors are able to determine aura strength as well, but are too bulky to be carried around normally.
As a result of being largely a biological functions, most practitioners of magic develop their innate talents rather than making a conscious decision to learn a particular form of magic. Learning a power that is not within an individuals talents is exceedingly difficult.