Book 12
11
Further, if there is to be nothing else besides sensible things, there will be no first principle, no order, no generation, and no celestial motions, but every principle will be based upon another,If there is nothing but what is sensible or potential, there can be no prime mover (which is actuality) to excite motion in the universe, and no teleology in causation. For the cosmologists on causation see Aristot. Met. 3.3.11-13. as in the accounts of all the cosmologists and physicists.
12
And if the Forms or numbers are to exist, they will be causes of nothing; or if not of nothing, at least not of motion.
12
Further, how can extension, i.e. a continuum, be produced from that which is unextended? Number cannot, either as a moving or as a formal cause, produce a continuum. Moreover, no contrary can be essentially productive and kinetic, for then it would be possible for it not to exist;
13
and further, the act of production would in any case be posterior to the potentiality. Therefore the world of reality is not eternal. But there are real objects which are eternal. Therefore one of these premisses must be rejected. We have described how this may be done.By assuming an eternal actual mover (Aristot. Met. 12.6.4).
13
Further, in virtue of what the numbers, or soul and body, or in general the form and the object, are one, no one attempts to explain; nor is it possible to do so except on our theory, that it is the moving cause that makes them one.Cf.Aristot. Met. 8.6.
14
As for thoseSpeusippus and his followers; cf. Aristot. Met. 7.2.4, Aristot. Met. 14.3.8. who maintain that mathematical number is the primary reality, and so go on generating one substance after another and finding different principles for each one, they make the substance of the universe incoherent (for one substance in no way affects another by its existence or non-existence) and give us a great many governing principles. But the world must not be governed badly:
