Was the creation of things at the beginning of time?
Summa Theologiae, Pars I, q. 46, a. 3
Article 3. was the creation of things at the beginning of time?
THE THIRD POINT: I. Seemingly not. For what is not in time is not in any part of time. Now the creation of things is outside time, for through it their substance was brought into existence. Time, however, is not the measure of substance, especially not that of bodiless things. Creation, therefore, was not at the beginning of time.
2. Again, Aristotle proves that everything which has become must previously have been in process of becoming, and so to become implies a before and after. When time began, since that was an indivisible moment, there was no before. Because, therefore, to be created is a kind of coming into being, it seems that things were not created when time began.
3. Further, time itself is also created. Yet not in its very start, since time is divisible whereas its starting moment is indivisible, Therefore the creation of things was not at the start of time.
ON THE OTHER HAND Genesis declares, In the beginning God created the heavens and the earth.
REPLY: This text has been interpreted in three ways in order to dispose of three errors.
First, some have proposed an everlasting universe and a time with no beginning; to counter this the phrase, In the beginning, is read to mean that time once started.
Secondly, some have proposed a dual origin to creation, one the principle of good things, the other of evil; to counter this the phrase, In the beginning, is read to refer to the Son of God. For as we think especially of the Father as efficient cause by the note of might so we think especially of the Son as exemplar cause by the note of wisdom. Accordingly the verse, In wisdom hast thou made them all, is understood to mean that God made all things in the beginning, that is the Son; as St Paul writes, He is the first-born of creation, for in him all things were created in heaven and on earth.
Thirdly, others have taught that bodily things were created by God through the intermediary of spiritual creatures; and to counter this the phrase, in the beginning, is read to mean before all things.
The four following are commonly supposed to have been created at once and together, namely the empyrean heavens, bodily matter (in other words, the earth), time, and angelic natures.
Hence: I. The phrase about things being created in the beginning of time means that the heavens and earth were created together with time; it does not suggest that the beginning of time was the measure of creation.
2. Aristotle is talking about the sort of coming to be which arises through change or is the term of a change. Whatever the change you take a before and after, and so before any one point in a designated change—that is while something is changing and becoming—there is another point before and also another one after; what is at the start or at the finish of change is not in the condition of being changed. Now, as we have seen, creation implies neither change nor a term of change. Hence a thing in not created in such a way that beforehand it was being created.
3. A thing is a fact just only as it exists. And time exists only as being now. Hence it can become a fact only because of some present moment.
This does not mean that time is in the original now, but that it begins then.
Summa Theologiae, I, q. 46, a. 3, edited by Blackfriars, translated by Thomas Gilby (London-New York: Eyre & Spottiswoode - McGraw-Hill, 1967), vol. 8, pp. 85-89.