The Book of Genesis is comprised of a series of family histories (Hebrew tôledôt) of the great patriarchs, from Adam to Joseph.
Genesis therefore is made up of a series of books, or diaries; the first of which covers verses 1:1-2:4 and is called The Book of the Heavens and the Earth; the title being taken from its opening line: “In the beginning God created the heavens and the earth” (1:1). The Septuagint in fact tells us that this section of Genesis was a written account, or book (Hebrew sêpher): “God made the written account of the origin of the heavens and the earth”. In other words, God was not creating the universe during those Six Days. He had already done that in the beginning, all at once. That is why Exodus 20:11 and 31:17, when referring to God’s activity during the Six Days, do not once use the Hebrew word for create (bara), but use the far more flexible in meaning, asah. (See ‘The Nature of God’s Creative Act’ above).
What God apparently was doing was writing a book for an already existing Adam and Eve. It was like a day-class with God as Teacher. The Almighty was doing what He would later do on Mount Sinai, in the presence of Moses: making a revelation and writing down on tablets what He wanted to be preserved in perpetuity, engraved in stone.
Regarding the meaning of the ‘Six Days’ (Gk. Hexaëmeron), debate has tended to divide commentators into two camps, namely:
There is no doubt that by far the majority of the Fathers favoured the so-called literalist interpretation of the Hexaëmeron. We can name here such luminaries as Sts. Basil, Jerome, Chrysostom, Ephrem. (The Syro-Arabic, Jewish and Persian commentators also definitely favoured the view that God created the world during Six Days).
But not all the Fathers of the Church accepted this interpretation.
The famous Alexandrian School, which included of course St. Clement, and the erudite Origen, preferred a more allegorical approach - which, however, needs to be distinguished from that of the ‘theistic’evolutionists. Origen ridiculed the notion of a creation that lasted during six days. And even the proponents of this approach have to concede that there are significant problems with it, for example:
Not to mention the metaphysical difficulty discussed above of how God’s creative act could have had temporal duration; directly in conflict, it seems, with the quotation from Sirach 18:1. Omnia simul, God created all things at once!
The fact that the so-called literalist approach has not been fully able to deal with all the contingencies of the Genesis text - despite the weight behind it of so many Church Fathers (amongst whom, it should be noted, there was nevertheless great variety of interpretation) - could lead us to conclude that in this case there may be need to, as Pope Leo XIII said, go “beyond” the Fathers [in Providentissimus Deus, 1893, II, C, d. Emphasis added]:
But [the expositor of the Bible] must not on that account [i.e., of duty to “follow the footsteps” of the Fathers “with all reverence”, # c.] consider that it is forbidden, when just cause exists, to push inquiry and exposition beyond what the Fathers have done; provided he carefully observes the rule so wisely laid down by St. Augustine - not to depart from the literal and obvious sense, except only where reason makes it untenable or necessity requires [De. Gen ad Litt., viii, 7, 13]; a rule to which it is more necessary to adhere strictly in these times, when the thirst for novelty and unrestrained freedom of thought make the danger of error most real and proximate.
Turning now from the literalist to the allegorical approach, we can say that well-known from ‘creationist’ literature are the problems encountered by the ‘theistic’ evolutionists and others. As said above, the Hebrew word yom is clearly pointing to a 24-hour day, which fact Genesis 1 reinforces by adding “evenings” and “mornings”. But the evolutionist approach cannot come to grips with - account for - any of this.
Certainly there is merit in some of the things that both sides have put forward. But, insofar as they have generally insisted that Genesis 1 is about the duration of God’s work of creation, they have all been barking up the wrong tree. The Bible and the Church’s omnia simul tells us that there was no duration because God is outside time.
As St. Augustine rightly perceived, Genesis is a revelation, by the Creator to the creature, of His works of creation already completed.
Sts. Thomas and Albert the Great thought that Augustine’s view here was the best of all interpretations of the text. Apparently, therefore, God was the direct author of Genesis 1, and it was He who “finished” (Genesis 2:1) writing the series of tablets - not “finished” the creation of the universe, as is often thought - just as later He “finished” (Exodus 31:18) the “two tablets” that He gave to Moses on Mount Sinai.
One usually finds that the proponents of the literalist interpretation of Genesis 1 are not all that literal. And the problem is their general ignorance of the Hebrew language. They get right the meaning of the Hebrew word, yom, as a 24-hour day. But, because they cannot cope with the precise meaning of the other important Hebrew words used in the text, they come up with the theory that God was creating the universe over six such days.