Samuel Clarke’s A Demonstration of the Being and Attributes of God is one of the great works of natural theology. But Clarke’s position is nevertheless in several respects problematic from a Thomistic point of view. For example, Clarke, like his buddy Newton, takes an absolutist view of time and space. Aristotelian-Thomistic philosophy of nature does not take an absolutist position (though it does not exactly take a relationalist position either). There are independent metaphysical reasons for this, but for the moment I want to focus on a theological problem.
As Thomists sometimes point out, the absolutist position makes space and time infinite and uncreated, and thus effectively deifies them. Clarke and Newton don’t exactly deny this. They avoid making time and space out to be deities alongside God, though, by more or less making of them divine attributes. Recall that for Newton, famously, space is God’s sensorium. It essentially becomes identified with God’s omnipresence. Time becomes identical with his eternity, or rather with everlasting duration. God is brought into time.
The problems with this, from a Thomist (and more generally, classical theist) perspective, should be obvious. Space is extended. God is not. Time entails change. God is changeless. And if space and time are divine attributes, then we have to take a pantheist or at least panentheist view of the natural world. For the most general features of nature would then be aspects of God.
William Lane Craig thinks this isn’t quite right. He writes:
Newton… declares explicitly that space is not in itself absolute and therefore not a substance. Rather it is an emanent – or emanative – effect of God. By this notion Newton meant to say that time and space were the immediate consequence of God's very being. God's infinite being has as its consequence infinite time and space, which represent the quantity of His duration and presence. Newton does not conceive of space or time as in any way attributes of God Himself, but rather, as he says, concomitant effects of God. (Time and Eternity, p. 46)
Putting aside questions of Newton exegesis, would this get Clarke and Newton out of the frying pan? Only by landing them in the fire. For if time and space are “concomitant effects” or “the immediate consequence” of “God's very being,” then their existence follows of necessity from his. And there are several problems with this thesis.
First, it would entail that the act of creation was not free (or at least that the creation of space and time was not free). For according to this thesis, God cannot not create time and space. But freedom is one of the divine attributes, knowable even by way of purely philosophical argumentation. (See e.g. Summa TheologiaeI.19.10; Summa Contra GentilesI.81, I.88 and II.23; Five Proofs of the Existence of God, pp. 224-228.)
Second, for God to create of necessity would detract from his perfection. As Aquinas argues in Summa TheologiaeI.19.3:
God wills things apart from Himself in so far as they are ordered to His own goodness as their end. Now in willing an end we do not necessarily will things that conduce to it, unless they are such that the end cannot be attained without them; as, we will to take food to preserve life, or to take ship in order to cross the sea. But we do not necessarily will things without which the end is attainable, such as a horse for a journey which we can take on foot, for we can make the journey without one. The same applies to other means. Hence, since the goodness of God is perfect, and can exist without other things inasmuch as no perfection can accrue to Him from them, it follows that His willing things apart from Himself is not absolutely necessary.
End quote. So, if this is correct, then if God is perfect, his willing of things other than himself is not necessary. But then, if his willing of things other than himself (in particular, time and space) isnecessary, then by modus tollens he is not perfect.
Similarly, in Summa Contra GentilesII.23.8, Aquinas argues that since “agents which act by will are obviously more perfect than those whose actions are determined by natural necessity,” God must be free.
A third problem is that if the existence of time and space follows necessarily from God’s existence, then not only did they have no beginning but they in principle could not have had a beginning. This would not conflict with classical theism per se, but it would conflict with any version of classical theism which incorporates biblical revelation.
Fourth, we have a conflict with Catholic orthodoxy. The First Vatican Council teaches:
If anyone says that finite things, both corporal and spiritual, or at any rate, spiritual, emanated from the divine substance… let him be anathema.
If anyone… holds that God did not create by his will free from all necessity, but as necessarily as he necessarily loves himself… let him be anathema.
Fifth, the position Craig attributes to Newton is not really a coherent one, at least not on a Thomistic metaphysical analysis. For the position in question essentially holds that time and space cannot not exist and yet are not divine attributes. But if they cannot not exist, then time and space must be purely actual and there must be in them no distinction between essence and existence. But in that case they are divine attributes, since only of God can these things be said. On the other hand, if they are not divine attributes, then they must not be purely actual and there must be in them a distinction between essence and existence. In that case, though, it is false to say that they cannot not exist, since anything that is less than pure actuality, and anything in which there is a distinction between essence and existence, can in principle fail to exist.
So, there just is no sense to be made of the idea that there is something distinct from God that he cannot not create. If he cannot not create it then that is only because it cannot not exist, in which case it is purely actual and subsistent being itself and thus really identical with God. If it is really distinct from God, then it is not purely actual or subsistent being itself, and thus it can fail to exist and God can refrain from creating it. The supposed middle ground position between pantheism on the one hand, and affirming the contingency of time and space on the other, is an illusion.