From the Almagest

From the Almagest:
It seems to me that these true philosophers, Syrus, very wisely separated the theoretical part of philosophy from the practical. For even if this happens, practicality will prove to be theoretical before it becomes practical, but one can find a great difference in them; not only because some moral virtues may belong to the everyday unconscious man and one cannot come to the theory of entire sciences without learning, but also because in practical matters the biggest advantage is the continuous and repeated operation of things in themselves, while in knowledge theoretical should be followed. Therefore, we thought about practicing our activities even in the application of imagination, not to forget about everything that would happen, taking into account their beautiful and well-ordered disposition, and devote ourselves to meditation mainly to make many beautiful statements, and especially those called mathematics.
 In fact, Aristotle quite correctly divides theory into three direct types: physical, mathematical and theological. Considering that all beings have their existence from matter, form and movement, and that none of them is visible, but only thoughts in their subject separately from others, if one should look in their simplicity for the first cause of the first cause by moving in the universe , he would consider God invisible and unchanging. And the science that seeks Him is theology; for such an act can only be considered high above somewhere near the highest things in the universe and is absolutely independent of reasonable things. But a kind of science that tracks this material and constantly moving quality and is related to white, warmth, sweetness, softness and such things would be called physics; and such an essence, because it is only what it is, is found in corrupt things and below the lunar sphere. And a kind of science that shows quality in terms of forms and local movements, character search, number and size, as well as place, time and similar things would be defined as mathematics. For such an essence falls somewhere between the other two, not only because it can be felt with both senses and without senses, but also because it is the case of absolutely all mortal and immortal beings, things that change with them always change , according to their irreversible form, and maintaining the unchangeable form immutability in eternal and ethereal things.