Jacques Maritain Center : Natural Theology / by Bernard Boedder, S.J.

SECTION 8. -- Aristotle's reasons for the necessity of eternal motion. Similar modern arguments from the writings of Kant and Cousin.

128. Aristotle was a monotheist, but he did not understand the dependence of the universe upon the free-will of its Creator, and therefore fell into the error of advocating the necessity of eternal motion. By motion he means not only local change, but every change in bodies, and it is his opinion that God, the self-existent immoveable mover of all things, if He caused the existence of a universe in motion, must have caused it from eternity. In support of this position, Aristotle brings forward three arguments, of which the second and third are repeated in another form by Kant and Cousin.

129. His first argument is this:{70} Before a body can be changed, it must exist. But it cannot come into existence except in virtue of a change, and this change supposes another change, and so on to infinity in the past. Consequently matter has been changing from eternity.

Answer. Granting the major of the argument, we deny the minor. A changeable body can originate by creation out of nothing, a mode of origin which does not contain a process of change, as proved above. (Cf. Th. XIV. § 84.)

130. Second Argument of Aristotle. -- Where time is, motion is. But time had no beginning; for every moment of time is the end of past and the beginning of future time. Consequently there was no first moment.

Answer. Again we have no objection to the major, but we must deny the minor. The truth underlying the statement made in the minor is this, that there must always have been duration. But there is a great difference between duration in general, and that special form of duration called time. Duration is a general term simply denoting persistency of existence. Time is a particular kind of duration of which the characteristic is succession; a new phase of being ever succeeding in the place of another which ceases to be. Time, therefore, supposes things liable to change. So far as it signifies the common measure of the durations of transitory existences and actions in our globe, it is in reality nothing else but the continual rotation of the earth round its axis, which by the observing mind of mankind has been divided into its natural parts, each consisting of one day and one night, of which all our artificial divisions of time are either parts or multiples. From this it is evident that time must have had a beginning no less than succession, as we have shown above. (p. 146.) The only duration which must have been without heginning is the unceasing existence of the one infinite Godhead.

Bearing this in mind, we can meet the turn by which Aristotle tries to strengthen his second argument. He says: If there was a beginning of time, then there was no time before the first moment of time. But this cannot be allowed; for he who says "before" indicates time past. It is therefore impossible that time had a beginning.

The answer is this: You can only say "before the first moment of time," if you mean to use the phrase in reference to an imaginary backward prolongation of it, devised by the mind as an aid to language: or else it denotes only the eternal duration, the unchangeable persistency in existence of the Divine Being. Ordinarily speaking, the first of these alternatives is that which is actually present to the mind of the speaker who uses the expression "before the first moment of time," or "before the first moment of the existence of created things liable to changes."

Similar to that of Aristotle is the following reasoning of Kant: "Let us assume that it (the world) had a beginning. Then as beginning is an existence which is preceded by a time in which the thing is not, it would follow that antecedently there was a time in which the world was not, that is, an empty time. In an empty time, however, it is impossible that anything should have its beginning, because of such a time no part possesses any condition of existence or non-existence to distinguish it from another."{71} We answer, that empty time is no time. There was no real time before the beginning of the world. God alone existed, and made the beginning of time by creating the world. But God's duration is unchangeable eternity. Therefore the beginning of the world was preceded by eternity, not by time.

131. Third Argument of Aristotle. -- The origin of all motion is ultimately due to God, the first absolutely unchangeable cause. But the first absolutely unchangeable cause cannot produce motion except from eternity to eternity: for otherwise He would undergo change Himself. It is therefore impossible that motion if existent should ever have had a commencement.

Answer. The proposition that a cause which continues unchanged cannot have an effect now, unless it has had the same effect before and will have it afterwards, holds good only on the supposition that the cause produces its effect by natural necessity. It is in no way applicable to God, who calls His creatures into existence by an eternal free decree of His will, and by the same decree determines the limits of their existence and motion, both in time and manner. We have already suggested as a help to realize this compatibility of the creative exercise of Divine free-will with the non-eternity of the effects, the analogy of the relation of the exercise of the human free-will to its effects in the moral order. The decrees of the sovereign, though all made together, come into effect at various times, some sooner, others later. There is no need of any contemporaneousness between the commencement of the effects and the determinations of sovereign will by which they are caused. We do not propose this illustration as an argument, but rather as an analogy which enables the mind to conceive to itself under some concrete form the mode of action which we are led by due course of reasoning to attribute to the Divine exercise of free-will. From this illustration we are entitled to gather at least this much, that, if the Divine will is able to produce physical realities of itself, by its sheer exercise, and if the decree of that will persists unchangeable, as it was conceived from eternity, then no further difficulty arises from the non-contemporaneousness of the commencement of the effect with a corresponding commencement of the Divine decree which is its cause.{72} That the Divine will is thus effective, we prove from the infinity of the Divine Nature.

With the argument of Aristotle may be compared the assertion of Victor Cousin, that God is the one absolute and infinite substance, and as such is essentially a cause. Consequently, argues this author, He cannot abstain from producing effects.{73}

To this our reply is, that God is essentially a cause only inasmuch as by virtue of His essence He can cause, but not as though His essence determined Him irresistibly to create finite things. As we have proved in the fourth chapter, God chose freely from eternity the act of creation, being able not to choose it. And as He has chosen the act itself, so He has freely fixed the moment of the beginning of His creatures.

{7O} We give here Aristotle's reasons in a compendious form. See the text in Aristotle's Physics, Lib. VIII. cc. i. vi. and St. Thomas in his commentary in Lib. VIII. Physicorum, Lect. 2, especially from n. 16 to the end, and Lect. 13, n. 8 towards the end.

{71} Cf. Kant's Critique of Pure Reason, by M. Müller, Vol. II. p. 369.

{72} Cf. pp. 138, seq.

{73} Cf. Cousin, Cours de 1828, Leçon v. p. 26.

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