Magic As Metaphors:
In this world magic is manipulated via metaphor, and most wizards have their own preferred ones. Theda tends to default to textile metaphors; for her, magic is thread, and it can be spun, woven, sewn, etc. While Cabalines believe magic can only be worked by channeling it through physical objects, Eusebians learn both that method and a method of casting spells by manipulating raw magic. Particularly skilled Eusebian wizards, a category that includes Theda, can also use this technique to create spells on the fly if they must, though these spells are often rather sloppy.
It's possible to use undirected magic -- say you're attacked without warning, so you instinctively lash out with your magic to defend yourself -- but doing so is just as dangerous to you as it is to the attacker and any bystanders, and you may not survive.