Since it seemed difficult to him to make a definite decision on this question, he began to consider within himself what would be the necessary consequence which did follow from either of those opinions, and that they might both be alike. And he perceived that, if he supposed the world to be created in time, and to have had an existence after non-existence, it would necessarily follow therefrom that the world could not come forth into existence by its own power, but required some agent to produce it; but this agent could not be perceived by any of the senses; for if it were an object of the senses, it would be body, and if body, part of the world, and would have had its existence anew; so that it would have stood in need of some other cause which should have produced it anew. And if this second creator were also a body, he would depend upon a third, and that third upon a fourth, and so on ad infinitum, which, however, would be absurd and irrational.
The world, therefore, must necessarily have a creator that has not a bodily substance; and as the creator is, indeed, without such a bodily substance, it is quite impossible for us to apprehend him by any of our senses; for we perceive nothing by the help of the five senses but bodies or such qualities as adhere to bodies.
And since it cannot be apprehended by sense, neither can it be comprehended by imagination. For imagination is nothing else but a representation of the forms of things, when their bodily objects are absent. And seeing it is not a body, we must not attribute to him any bodily properties, the first of which is extension into length, breadth, thickness; but he is free from that, and also from all other properties of body that flow from it. And seeing he is the Creator of the world, doubtless he knows whatsoever is in it, and has the sovereign command over it. “Shall not he know, that created it? For he is most eminent in knowledge and omniscient.” (Koran.)
On the other side he saw that if he believed in the eternity of the world, and that it was ever as it is now, and that no time of chaos preceded it, that necessarily it would follow that motion was from eternity also, without any period of beginning, because there could be no rest before it whence to take its beginning.
Now, every motion necessarily requires a mover, and that mover is either some power diffused in some body, to wit, either in the body of the thing moved or else through some other body without it, or else some other power that is not diffused or dispersed through anything at all.
Now every power diffused in any body and dispersed through it, is divided or doubled. For example: gravity in a stone which causes it to move downwards. For if the stone be divided into two parts, the gravity is also divided into two parts; and if you add thereto another stone of equal weight, the gravity is doubled. And if it were possible that the stone grew ad infinitum, the gravity would also grow ad infinitum. On the other hand, if the stone should grow to a certain size and remain there, also the gravity would increase to the same extent, and no farther.
Now it has already been demonstrated that every body must necessarily be finite, and consequently every power inherent in a body is also finite. If, therefore, we can find a power which produces an infinite effect, it must needs be such a power that is not inherent in any body.
Now we find that the heaven is moved with a perpetual motion, without any cessation at all.
Therefore, if we affirm that its motion has no beginning, it necessarily follows that the power that moves is not inherent in its own body nor in any other body that is without it; but proceeds from something altogether abstract from bodies, and which can be described by no terms applicable to bodies.
Then it was evident to him, from his former contemplation of the lower world which is liable to generation and corruption, that the true essence of body consisted in its form, which is its disposition to various motions, but that that part of its essence which consisted in matter was very mean and poor, and can scarcely be conceived. Therefore the existence of the whole world consists in its disposition to be moved by this Mover, who is free of all matter and of all adjuncts belonging to the body, abstracted from everything which senses can apprehend or imagination can reach.