Thomas Aquinas

“ Further, nothing which has power to be always, sometimes is and sometimes is not; because so far as the power of a thing extends so long is exists. But every incorruptible thing has power to be always; for its power does not extend to any determinate time. Therefore no incorruptible thing sometimes is, and sometimes is not: but everything which has a beginning at some time is, and at some time is not; therefore no incorruptible thing begins to exist. But there are many incorruptible things in the world, as the celestial bodies and all intellectual substances. ”

“ It would seem that it is not an article of faith but a demonstrable conclusion that the world began. For everything that is made has a beginning of its duration. But it can be proved demonstratively that God is the effective cause of the world ”

“ If therefore the world began to exist, it was a possible being before it began to exist. But possible being is matter, which is in potentiality to existence, which results from a form, and to non-existence, which results from privation of form. If therefore the world began to exist, matter must have existed before the world. But matter cannot exist without form: while the matter of the world with its form is the world. Therefore the world existed before it began to exist: which is impossible. ”

“ Before the world existed it was possible for the world to be, not, indeed, according to a passive power which is matter, but according to the active power of God; and also, according as a thing is called absolutely possible, not in relation to any power, but from the sole habitude of the terms which are not repugnant to each other ”

“ But it is not impossible to proceed to infinity "accidentally" as regards efficient causes; for instance, if all the causes thus infinitely multiplied should have the order of only one cause, their multiplication being accidental, as an artificer acts by means of many hammers accidentally, because one after the other may be broken. It is accidental, therefore, that one particular hammer acts after the action of another; and likewise it is accidental to this particular man as generator to be generated by another man; for he generates as a man, and not as the son of another man. ”

“ Further, it appears manifestly that certain arts have developed, and certain countries have begun to be inhabited at some fixed time. But this would not be the case if the world had been always. Therefore it is manifest that the world did not always exist.
Objection 5: Further, it is certain that nothing can be equal to God. But if the world had always been, it would be equal to God in duration. Therefore it is certain that the world did not always exist. ”

“ But neither begins to move except by some pre-existing movement. For nature always moves in the same manner: hence unless some change precede either in the nature of the mover, or in the movable thing, there cannot arise from the natural mover a movement which was not there before. And the will, without itself being changed, puts off doing what it proposes to do; but this can be only by some imagined change, at least on the part of time. Thus he who wills to make a house tomorrow, and not today, awaits something which will be tomorrow, but is not today ”

“ Those who hold the eternity of the world evade this reason in many ways. For some do not think it impossible for there to be an actual infinity of souls, as appears from the Metaphysics of Algazel, who says that such a thing is an accidental infinity. ”

“ Hence it is not impossible for a man to be generated by man to infinity; but such a thing would be impossible if the generation of this man depended upon this man, and on an elementary body, and on the sun, and so on to infinity. ”

“ For we must take into consideration the difference between a particular agent, that presupposes something and produces something else, and the universal agent, who produces the whole. The particular agent produces the form, and presupposes the matter ”

“ Hence it is evident that this reason, which Aristotle gives (Phys. viii) , is valid against those who admitted the existence of eternal movable things, but not eternal movement, as appears from the opinions of Anaxagoras and Empedocles. But we hold that from the moment that movable things began to exist movement also existed.
Reply to Objection 6: The first agent is a voluntary agent. And although He had the eternal will to produce some effect, yet He did not produce an eternal effect. Nor is it necessary for some change to be presupposed, not even on account of imaginary time. ”

“ Passage is always understood as being from term to term. Whatever bygone day we choose, from it to the present day there is a finite number of days which can be passed through. The objection is founded on the idea that, given two extremes, there is an infinite number of mean terms. ”