The universe is generally thought to be pervaded by a magiferous aether, a substance now believed to be composed of particles called magions, which have highly complex internal state. Magions, in their neutral state, do not interact with normal matter, and weakly repel each other such that they assume a uniform distribution in free space. However, in their various higher-energy states they can temporarily assume numerous different apparent properties. Magions can even convert energy into matter by first being excited to an appropriate state, and then returning to a lower-energy state with the release a baryon. All known magical effects can be described on a fundamental level in terms of the behavior of magions and thaumatons, although this is arguably tautological since magical physics could equally well be defined as the study of magions, thaumatons, and their interactions with each other and ordinary matter and energy.
Magions, in non-neutral states, can come to have attractions to each other and the world of normal matter, such that they effectively adhere to each other and to some specific collection of matter. Bound magions are the basis for persistent enchantments, and the subtle waves of displaced magions make most enchanted objects and magical creatures easy to notice for the sensate.