The mode of existence (διαγωγή) of this Prime Movent is for ever that which we enjoy in our best moments, but which we cannot obtain permanently; for its actuality itself is also pleasure (p. 1072, b. 16). As actuality is pleasure, so the various actualities of waking, perceiving, cogitating, are to us the pleasantest part of our life; while hopes and remembrances are pleasing by derivation from them (but these states we men cannot enjoy permanently and without intermittence). Cogitation per se (i.e., cogitation in its most perfect condition) embraces that which is best per se; and most of all when it is most perfect. The Noûs thus cogitates itself through participation of the Cogitabile: for it becomes itself cogitable by touching the Cogitabile and cogitating: so that Cogitans and Cogitabile become identical. For Noûs in general (the human Noûs also) is in potentiality the recipient of the Cogitabile, and of Essentia or Forms; and it comes into actuality by possessing these Forms. So that what the Prime Movent possesses is more divine than the divine element which Noûs in general involves; and the actuality of theorizing is the pleasantest and best of all conditions (νοητὸς γὰρ γίγνεται θιγγάνων καὶ νοῶν, ὥστε ταὐτὸν νοῦς καὶ νοητόν. τὸ γὰρ δεκτικὸν τοῦ νοητοῦ καὶ τῆς οὐσίας νοῦς. ἐνεργεῖ δὲ ἔχων· ὥστ’ ἐκεῖνο μᾶλλον τούτου ὃ δοκεῖ ὁ νοῦς θεῖον ἔχειν, καὶ ἡ θεωρία τὸ ἥδιστον καὶ ἄριστον — b. 24. This is a very difficult passage, in which one cannot be sure of interpreting rightly. None of the commentators are perfectly satisfactory. The pronoun ἐκεῖνο seems to refer to ἡ νόησις ἡ καθ’ αὑτήν — three lines back. The contrast seems to be between the Prime Movent, and Noûs in general, including the human Noûs. Τὸ δεκτικόν cannot refer to the Prime Movent, which has no potentiality, but must refer to the human Noûs, which is not at first, nor always, in a state of actuality. Μᾶλλον seems equivalent to θειότερον. The human Noûs has θεῖόν τι, by reason of its potentiality to theorize.).
Thus it is wonderful, if God has perpetually an existence like that of our best moments; and still more wonderful, if he has a better. Yet such is the fact. Life belongs to him: for the actuality of Noûs is life, and God is actuality. His life, eternal and best, is actuality per se (or par excellence). We declare God to be an Animal Optimum Æternum, so that duration eternal and continuous (αἰὼν συνεχής) belongs to him: for that is God (τοῦτο γὰρ ὁ θεός — p. 1072, b. 30).
The Pythagoreans and Speusippus are mistaken in affirming that Optimum and Pulcherrimum is not to be found in the originating principle (ἐν ἀρχῇ); on the ground that the principles of plants and animals are indeed causes, but that the beautiful and perfect appears first in the results of those principles. For the seed first proceeds out of antecedent perfect animals: the first is not seed, but the perfect animal. Thus we must say that the man is prior to the seed: I do not mean the man who sprang from the seed, but the other man from whom the seed proceeded (p. 1073, a. 2).
From the preceding reasonings, it is evident that there exists an Essence eternal, immoveable, and separated from all the perceivable Essences. We have shown (in Physica; see Schwegler’s note) that this Essence can have no magnitude; that it is without parts and indivisible (p, 1073, a. 6). For it causes in other subjects motion for an infinite time; and nothing finite can have infinite power. For this reason the Prime Movent cannot have finite magnitude; but every magnitude is either finite or infinite, and there is no such thing as infinite magnitude; therefore the Prime Movent can have no magnitude at all. We have also shown that it is unchangeable in quality, and without any affections (ἀπαθὲς καὶ ἀναλλοίωτον). For all other varieties of change are posterior as compared with locomotive change or motion in space, which is the first of all. As the Prime Movent is exempt from this first, much more is it exempt from the others (a. 13).
We must now consider whether we ought to recognize one such Movent or Essence only, or several of the same Essences? and, if several, how many? Respecting the number thereof we must remember that our predecessors have laid down no clear or decisive doctrines (ἀποφάσεις, p. 1073, a. 16). The Platonic theory of Ideas includes no peculiar research on this subject (a. 18). The Platonists call these Ideas Numbers: about which they talk sometimes as if there were an infinite multitude of them, sometimes as if they were fixed as reaching to the dekad and not higher — but they furnish no demonstrative reason why they should stop at the dekad. We shall proceed to discuss the point consistently with our preceding definitions and with the nature of the subjects (a. 23). The Principium, the First of all Entia, is immoveable both per se and per accidens: it causes motion in another subject, to which it imparts the first or locomotive change, one and eternal (a. 25). The Motum must necessarily be moved by something; the Prime Movent must be immoveable per se; eternal motion must be caused by an eternal Movent; and one motion by one Movent (a. 30). But we see that, over and above the simple rotation of the All (or First Heaven), which rotation we affirm to be caused by the Primum Movens Immobile, there are also other eternal rotations of the Planets; for the circular Celestial Body, as we have shown in the Physica, is eternal and never at rest (a. 32). We must therefore necessarily assume that each of these rotations of the Planets is caused by a Movent Immoveable per se — by an eternal Essence (a. 35). For the Stars and Planets are in their nature eternal Essences: that which moves them must be itself eternal, and prior to that which it causes to be moved; likewise that which, is prior to Essence must itself be Essence, and cannot be any thing else (a. 37). It is plain, therefore, that there must necessarily exist a number of Essences, each eternal by nature, immoveable per se, and without magnitude, as Movents to the Heavenly Bodies and equal in number thereto (a. 38). These Essences are arranged in an order of first, second, &c., corresponding to the order of the planetary rotations (b. 2), But what the number of these rotations is, we must learn from Astronomy — that one among the mathematical sciences which is most akin (οἰκειοτάτης) to the First Philosophy; for Astronomy theorizes about Essence perceivable but eternal, while Arithmetic and Geometry do not treat of any Essence at all (περὶ οὐδεμιᾶς οὐσίας — b. 7). That the rotations are more in number than the rotating bodies, is known to all who have any tincture of Astronomy; for each of the Planets is carried round in more than one rotation (b. 10). But what the exact number of these rotations is, we shall proceed to state upon the authority of some mathematicians, for the sake of instruction, that the reader may have some definite number present to his mind: for the rest, he must both investigate for himself and put questions to other investigators; and, if he learns from the scientific men any thing dissenting from what we here lay down, he must love both dissentients but follow that one who reasons most accurately (φιλεῖν μὲν ἀμφοτέρους, πείθεσθαι δὲ τοῖς ἀκριβεστέροις — b. 16).
Aristotle then proceeds to unfold the number and arrangement of the planetary spheres and the corrective or counter-rolling (ἀνελιττούσας) spheres implicated with them (p. 1073, b. 17 — p. 1074, a. 14). He afterwards proceeds: Let the number of spheres thus be forty-seven; so that it will be reasonable to assume the Immoveable Movent Essences and Principles to be forty-seven also, as well as the perceivable spheres (αἰσθητάς — p. 1074, a. 16): we say reasonable (εὔλογον), for we shall leave to stronger heads to declare it necessary. But, since there cannot be any rotation except such as contributes to the rotation of one of the Planets, and since we must assume that each Nature and each Essence is exempt from extraneous affection and possessed per se of the Best as an end, so there will be no other Nature besides the forty-seven above enumerated, and this number will be the necessary total of the Essences (a. 21). For, if there were any others, they would cause motion by serving as an end for some rotation to aspire to (κινοῖεν ἂν ὡς τέλος οὖσαι φορᾶς — a. 23); but it is impossible that there can be any other rotation besides those that have been enumerated.
We may fairly infer this from the bodies which are carried in rotation (ἐκ τῶν φερομένων — p. 1074, a. 24). For, if every carrier exists naturally for the sake of the thing carried, and if every current or rotation is a current of something carried, there can exist no current either for the sake of itself or for the sake of some other current. Every current must exist for the sake of the Planets, and with a view to their rotation. For, if one current existed for the sake of another, this last must exist for the sake of a third, and so on; but you cannot go on in this way ad infinitum; and therefore the end of every current must be, one or other of the Divine Bodies which are carried round in the heavens (a. 31).
That there is only one Heaven, we may plainly see. For, if there were many heavens, as there are many men, the principium of each would be one in specie, though the principia would be many in numero (p. 1074, a. 33). But all things that are many in number, have Matter, and are many, by reason of their Matter; for to all these many, there is one and the same Form (λόγος) — definition or rational explanation: e.g., one for all men, among whom Sokrates is one (a. 35). But the First Essence has no Matter; for it is an Actual (τὸ δὲ τί ἦν εἶναι οὐκ ἔχει ὕλην τὸ πρῶτον· ἐντελέχεια γάρ — a. 36). The Primum Movens Immobile is therefore One, both in definition and in number; accordingly, the Motum — that which is moved both eternally and continuously — is One also. There exists therefore only one Heaven (p. 1074, a. 38).
Now it has been handed down in a mythical way, from the old and most ancient teachers (p. 1074, b. 1) to their successors, that these (Eternal Essences) are gods, and that the divine element comprehends all nature (ὅτι θεοί τέ εἰσιν οὗτοι καὶ περιέχει τὸ θεῖον τὴν ὅλην φύσιν — b. 3). The other accompaniments of the received creed have been superadded with a view to persuading the multitude and to useful purposes for the laws and the common interest (b. 4); wherefore the gods have been depicted as like to men and to some other animals, combined with other similar accompaniments. If a man, abstracting from these stories, accepts only the first and fundamental truth — That they conceived the First Essences as gods, he will consider it as a divine doctrine (θείως ἂν εἰρῆσθαι νομίσειεν — b. 9), preserved and handed down as fragments of truth from the most ancient times. For probably all art and philosophy and truth have been many times discovered, lost, and rediscovered. To this point alone, and thus far, the opinion of our fathers and of the first men is evident to us (b. 14).
There are however various difficulties connected with the Noûs; for it would seem to be more divine than the visible celestial objects, and yet we do not understand what its condition can be to be such (p. 1074, b. 17). For, if it cogitates nothing but is in the condition of slumber and inaction, what ground can there be for respecting it (τί ἂν εἴη τὸ σεμνόν — b. 18)? And, if it cogitates something actually, yet if this process depends upon something foreign and independent (i.e., upon the Cogitatum), the Noûs cannot be the best Essence; since it is then essentially not Cogitation in act, but only the potentiality of Cogitation; while its title to respect arises from actual Cogitation. Again, whether we assume its Essence to be Cogitation actual or Cogitation potential, what does it cogitate? It must cogitate either itself, or something different from itself; and, if the latter, either always the same Cogitatum, or sometimes one, sometimes another. But is there no difference whether its Cogitatum is honourable or vulgar? Are there not some things which it is absurd to cogitate? Evidently the Noûs must cogitate what is most divine and most honourable, without any change; for, if it did change, it must change for the worse, and that very change would at once (ἤδη) be a certain motion; whereas the Noûs is essentially immoveable (b. 27). First of all, if the Essence of the Noûs be, not Cogitation actual but Cogitation potential, we may reasonably conceive that the perpetuity of Cogitation would be fatiguing to it (b. 29); next, we see plainly that there must exist something else more honourable than the Noûs; namely, the Cogitatum; for to cogitate, and the act of cogitation, will belong even to one who cogitates the vilest object. If cogitation of vile objects be detestable (φευκτόν, b. 32) — for not to see some things is better than to see them — Cogitation cannot be the best of all things (i.e., Cogitation absolutely, whatever be the Cogitatum).