I think it's accurate to say that while Thomas begins with the material senses and ascends to the immaterial Principle, Schuon begins at the other end, with the Principle -- or Absolute -- and skis down the mountain to the manifestation below.
However, once Thomas rises to the Principle, he too schusses down the mountainside, taking everything below into consideration, as illuminated by the Principle(s).
Here's how Fr. Reg describes Thomas's vertical circularity: he
marches steadily onward to that superior simplicity..., a simplicity pregnant with virtual multiplicity.... the saint's progress is a slow, hard climb to the summit of the mountain, whence alone you can survey all these problems in a unified solution....
He exemplifies his own teaching on "circular" contemplation, which returns always to one central, pre-eminent thought, better to seize all the force of its irradiation. His principles, few in number but immense in reach, illumine from on high a great number of questions.
Again, the Great Cosmic Circle of coontomplation begins from below, ascends upward, and then returns down, only equipped with the principles that illuminate this downward path.
Herebelow, things can either exist or not exist, irrespective of their essence. Only at the summit of metaphysics do essence and existence converge, such that in God alone are they one: God's essence is to exist, and existence is his essence. This is the final truth arrived at by reason:
this supreme truth is the terminus, the goal, of the ascending road which rises from the sense world to God, and the point of departure on the descending road, which deduces the attributes of God and determines the relation between God and world.
Snowboarding back down,
Many positions which we have already met on the ascending road now reappear, seen as we follow the road descending from on high.
So, be nice to those discarnate nonlocal intelligences on the way up, because you'll meet the same ones on the way down.
For Schuon, all of this is true enough, except he would say it is possible to start at the summit -- or, to be more precise, the "meta-summit."
He would essentially say that there is Reality and that there are appearances, the latter being a consequence and prolongation of the former. Thus, appearances are at once distinct from the Principle, and yet "not not" the sophsame principle in the mode of appearances.
This realization is possible not just because of the ascent described by Thomas, but because we too are "not not" the Principle. Obviously we are not God, but the fact that we are in his image and likeness means we're not exactly not God either. Frankly, anything purely not-God would be nonexistent.
This brings to mind our two subjective centers -- the local material ego and the nonlocal self. Importantly, these are not a duality but a complementarity that -- in my opinion -- can be traced all the way up and in to God. For example, "Father" and "Son" are two subjectivities or "personal centers" within a radical unity.
. . . But we're out of time, so we'll pick up this towline of thought in the next. . .