This claim – that a disagreement over the proper interpretation of Genesis 1 predates modern geology – is true. Many of the early Christians were uncertain about the proper view of the Genesis account of creation. Some of the Church Fathers held to the view that the days of creation in Genesis 1 were literal, 24-hour days. Others, however, claimed that the duration of these days was uncertain. In nearly every case, those arguing for uncertainty in this matter held to the view that all the events of the creation week occurred on a single day and not over lengthy periods of time, but it is technically correct to claim that Christians have always disagreed in their interpretations of the days listed in Genesis 1.
The old earth creationists are very much in error, however, when they use this disagreement to imply that some of the Church Fathers would have accepted the old earth view. Nothing could be further from the truth. The very same writers that old earth proponents quote in support of the non-literal interpretation of the days of creation were some of the most vociferous defenders of the young age of the earth. For example, it is quite correct to point out that Augustine doubted the literal, 24-hour interpretation of the days in Genesis 1 when he wrote: “What kind of days these are is difficult or even impossible for us to imagine, to say nothing of describing them.” However, several pages later in the same book from which this statement is drawn, Augustine spoke of “The falsity of such history as ascribes to the world a past of many thousand years.” In regards to this error, Augustine said:
Those who hold such opinions are also led astray by some utterly spurious documents which, they say, give a historical record of many thousand years, whereas we reckon, from the evidence of the holy Scriptures, that fewer than 6,000 years have passed since man's first origin.
Here, Augustine clearly rejects the notion that the earth is older than 6,000 years, and he then proceeded to demonstrate the folly of those who argue otherwise by comparing the genealogies of Scripture with the records of the Greeks and the Egyptians in order to defend “the truth of the biblical narrative of the past.”
In addition to Augustine, Origen also expressed difficulties with the literal, 24-hour view of the days of creation when he wrote:
we found fault with those who, taking the words in their apparent signification, said that the time of six days was occupied in the creation of the world, and quoted the words: "These are the generations of the heavens and of the earth when they were created, in the day that the Lord God made the earth and the heavens.
However, just as we saw with Augustine, we find that Origen also included in the same book as the above statement another statement in which he decisively expresses his rejection of the old earth view. Origen wrote:
After these statements, Celsus, from a secret desire to cast discredit upon the Mosaic account of the creation, which teaches that the world is not yet ten thousand years old, but very much under that, while concealing his wish, intimates his agreement with those who hold that the world is uncreated ... And yet, against his will, Celsus is entangled into testifying that the world is comparatively modern, and not yet ten thousand years old.
And when speaking of the histories of Moses, Origen said that they were composed of language “which admits of no allegorical meaning!” Clearly, Origen has a strong disagreement with those who use his writings to defend the old earth view.
Some old earth creationists also invoke the writings of Clement of Alexandria in defense of their views, and it is again true that Clement sometimes expressed a non-literal understanding of the days of creation, but it is also true that he was an ardent defender of the young age of the earth. In his Stromata, he wrote:
From Adam to the deluge are comprised two thousand one hundred and forty-eight years, four days. From Shem to Abraham, a thousand two hundred and fifty years. From Isaac to the division of the land, six hundred and sixteen years. Then from the judges to Samuel, four hundred and sixty-three years, seven months. And after the judges there were five hundred and seventy-two years, six months, ten days of kings.
After which periods, there were two hundred and thirty-five years of the Persian monarchy. Then of the Macedonian, till the death of Antony, three hundred and twelve years and eighteen days. After which time, the empire of the Romans, till the death of Commodus, lasted for two hundred and twenty-two years ... and from Adam to the death of Commodus, five thousand seven hundred and eighty-four years, two months, twelve days.
Once again, we find that the very same Church Fathers that old earth creationists quote in defense of the non-literal view of the days of creation were actually some of the most fervent defenders of the young earth position. Thus, whether the Church Fathers are referenced as an appeal to authority or as merely a historical example, the truth of the matter is that the early Christian writers were unanimous in their defense of the young age of the earth.