The most suitable investigation concerning the first mover combines discussion of physical inquiry with metaphysical inquiry. I do not mean by ‘the first mover’ some particular mover, nor by ‘what moves by it’ some particular mobile, as the one did who surmised that when Aristotle demonstrated in the eighth treatise of the Physica that there is some first mover and some thing that moves by it primarily, and that the mover is in the circumference; he meant by ‘the first mover’ the being that is the First Cause, and by ‘the first mobile’ the sphere of the universe, and that this mover is in its circumference.
My view is that [Aristotle] discussed in that book the universal principles and the general canons of physical entities as such, and that he did not concern himself with their essences. This was so that the investigator of entities, in following a physical procedure, would comply with these canons, inasmuch as the truth concerning it is attained through them. The philosopher’s discourse, however, in which he made statements relating to entities, leads the imagination to what was surmised. And this is how most of what he stated in the Metaphysica ought to be regarded; for the objective of inquiry is to pave the way and to provide understanding of the correct procedure toward the subjects of investigation proper to the two philosophies, I mean natural philosophy and divine philosophy, so that the investigator of the real essences of existents may employ them.
In my view, Aristotle was distinguished by this kind of philosophic inquiry from the ancients who preceded him; for they tended to confuse inquiry concerning essences with inquiry concerning statements aimed at knowing their conditions and the syllogisms and rules indicating their validity. [Aristotle], however, reserved inquiry concerning syllogisms, rules and general canons of the intelligible, the object of opinion, what is naturally constituted, and what has a material substrate, for logic, which comprises demonstrative, dialectic and other arguments, for which verification and assent are required. He then produced natural philosophy, reserving inquiry concerning the rules and general canons regarding entities insofar as they are natural for the Physica. He then produced the divine science, reserving inquiry concerning the paths leading to it for what he asserted in the books of the Metaphysica. Inquiry in the Metaphysica does not concern the essences of the divine entities; it concerns rather the manner of investigating the essences insofar as they are divine.
And now I shall return to what we intended to discuss, having mentioned something that is not the specific matter of investigation in this place. We say: Every first mover, insofar as it is such, has a first mobile. And the first mobile, insofar as it is such, has the motion most deserving of priority, namely locomotion, and of it the noblest motion of its kind, namely, circular motion.
Everything that moves does so either essentially or accidentally. What moves essentially is prior to what moves accidentally. And the first mobile, which moves by a first mover, is prior to and nobler than everything that moves essentially. What moves essentially is first; hence, the first mobile of a first mover is the first that moves essentially.
What moves essentially contains its principle of motion. Every body that contains its principle of motion is a natural body, and that notion from which the principle of its motion derives is natural. The motion of every mobile and mover exists in the mobile rather than in the mover. The rotary mobile, which contains its principle of motion, and owing to which motion exists, is the circumference rather than the centre. The first mover, then, is in the circumference of every rotary mobile rather than the centre. And the first mover is a natural form for the first rotary mobile and is moved accidentally. However, the mover that does not move accidentally is nobler than the mover that does. Since this is so, there exists some mover that does not move in any respect. For whatever is accidental comes after what is essential, and a part of it is present in whatever it is posited.
Early Islamic Philosophical Figures in Persia: Abu Sulayman Muhammad Ibn Tahir Sijistani
