‘The third theory is that of Aristotle, who holds that the Agent produces at once both form and substance, by impressing motion on matter, and begetting a change therein which rouses its latent powers to action. In this way of thinking the function of the Agent is only to make active that which already existed potentially, and to realise a union between matter and form. Thus all creation is reduced to motion of which heat is the principle. This heat, shed abroad in the waters and in the earth, begets both the animals and the plants which are not produced by seed. Nature puts forth all these both orderly and with perfection, just as if guided by a controlling mind; though nature itself has no intelligence. The proportions and productive power which the elements owe to the motion of the sun and stars are what Plato called by the name of _Ideas_. According to Aristotle the Agent cannot create forms, for in that case something would be produced from nothing. ‘It is, in fact, the notion that forms could be created which has led some philosophers to suppose that forms have a substantive existence of their own, and that there is a separate source of these. The same error has infected all the three religions of our day,[184] leading their divines to assert that nothing can produce something. Starting from this principle our theologians have supposed the existence of one Agent producing without intermediary all kinds of creatures; an Agent whose action proceeds by an infinity of opposite and contradictory acts done simultaneously. In this way of thinking it is not fire that burns, nor water that moistens; all proceeds by a direct act of the Creator. Nay more, when a man throws a stone, these teachers attribute the consequent motion not to the man but to the universal Agent, and thus deny any true human activity. ‘There is even a more astounding corollary of this doctrine; for if God can cause that which is not to enter into being, He can also reduce being to nothing; destruction, like generation, is God’s work, and Death itself has been created by Him. But in our way of thinking destruction is like generation. Each created thing contains in itself its own corruption, which is present with it potentially. In order to destroy, just as to create, it is only necessary for the Agent to call this potentiality into activity. We must in short maintain as co-ordinate principles both the Agent and these potential powers. Were one of the two wanting, nothing could exist at all, or else all being would reduce itself to action; either of which consequences is as absurd as the other.’