My thoughts are the basic magics are powered by ley lines, deeper is powered by the casters own personal energies, and higher energies are the caster channeling into and manipulating one of the infinite powers of the universe. Each rank seems to be more powerful, more difficult to control, and slower to level (unless your soul is perfectly attuned to a type of energy) Lots we don't know here. The poll is one example, what are the penalties of higher education magic, are there deeper magics and higher energies we don't know about, where do things like celestial and abyssal magic fall into this, are there interactions/mandalas for deeper/higher magics or only the basic elements. So many questions..
Im thinking space and matter could be some other higher magics. Ability to teleport at will, and ability to make something out of nothing.