By some? Do you mean some small clued up scientifically literate section of the Christian community? And you want to quote him as a means to indicate that people did NOT think that the world was 6,000 years old? Well, over to you, Augustine
ccel.org/ccel/schaff/npnf102.iv.XII.10.html: (my emphasis):
‘They are deceived, too, by those highly mendacious documents which profess to give the history of many thousand years, though, reckoning by the sacred writings, we find that
not 6000 years have yet passed.’[20]
However, what we have seen, and what we have just had confirmed by no less than Augustine himself, ‘best available knowledge’ at the time was a creation lasting 6 days and the age of the world to be 6,000 years. I mean, the guy actually gives that figure himself.
Are you now going to say that Augustine can be trusted…
It isn’t clear where the Patristic Fathers stood in the matter because they were all over the map on the issue and were still trying to make sense of it.
ST. JUSTIN MARTYR: For as Adam was told that on the day he ate of the tree he would die, we know that he did not complete a thousand years. We have perceived, moreover, that the expression “The day of the Lord is as a thousand years” is connected with this subject [Dialogue with Trypho 81 (c. A.D. 155)].
ST. CLEMENT OF ALEXANDRIA And how could creation take place in time, seeing time was born along with things that exist? .
.. So that we may be taught that the world was originated [in this way], and not suppose that God made it in time, prophecy adds: “This is the book of the generation: also of the things in them, when they were created in the day that God made heaven and earth.” **For the expression “when they were created” intimates an indefinite and dateless production. **[Miscellanies 6:16 (c. A.D. 207)].
ORIGEN OF ALEXANDRIA
For who that has understanding will suppose that the first, and second, and third day, and the evening and the morning, existed without a sun, and moon, and stars? And that the first day was also without a sky? And who is so foolish as to suppose that God, after the manner of a husbandman, planted a paradise in Eden, towards the east, and placed in it a tree of life, visible and palpable, so that one tasting of the fruit by the bodily teeth obtained life? And again, that one was a partaker of good and evil by eating the fruit? And if God is said to walk in the paradise in the evening, and Adam to hide himself under a tree, **I do not suppose that anyone doubts that these things figuratively indicate certain mysteries, the history having taken place in appearance, and not literally **[Fundamental Doctrines 4:16 (c. A.D. 225)].
And since [the pagan Celsus] makes the statements about the “days of creation” ground of accusation, as if he understood them clearly and correctly, some of which elapsed before the creation of light and heaven, the sun and moon and stars, and some after, we shall only make this observation, that Moses must have forgotten that he had said a little before “that in six days the creation of the world had been finished” and that in consequence of his forgetfulness he adds to these words the following: “
This is the book of the creation of man in the day when God made the heaven and the earth” [Gn 2:4] [Against Celsus 6:51 (c. A.D. 248)].
Translation: Moses must have forgotten that he claimed God made the world in six days when in Genesis 2:4 he says it was one day.
ST. AUGUSTINE OF HIPPO There is knowledge to be had, after all, about the earth, about the sky, about the other elements of this world, about the movements and revolutions or the magnitude and distances of constellations, about the predictable eclipses of moon and sun, about the cycles of years and seasons, about the nature of animals, fruits, stones, and everything else of this kind. And it frequently happens that even non-Christians have knowledge of this sort that they can substantiate with scientific arguments or experiments. Now it is quite disgraceful and disastrous, something to be on one’s guard against at all costs, that they should ever hear Christians spouting what they claim our Christian literature has to say on these topics, and talking such nonsense that they can scarcely contain their laughter when they see them to be toto caelo, as the saying goes, wide of the mark. And what is so vexing is not that misguided people should be laughed at, as that our authors should be assumed by outsiders to have held such views and, to the great detriment of those about whose salvation we are concerned, should be written off and consigned to the wastepaper basket as so many ignoramuses.
..*.
It is in order to take account of this state of things that I have, to the best of my ability, drawn out and presented a great variety of possible meanings to the words of the book of Genesis that have been darkly expressed in order to put us through our paces. I have avoided affirming anything hastily in a way that would rule out any better alternative explanation, leaving everyone free to choose whichever they can grasp most readily in their turn [Literal Interpretation of Genesis 1:19–20 (c. A.D. 408)].
So for the sake of argument, let us suppose that these seven days [which we experience in a modern week], which in their stead [in the stead of the days of creation] constitute the week that whirls times and seasons along by its constant recurrence, in which one day is the whole circuit of the sun from sunrise to sunrise—that these seven [modern days] represent those first seven [days of creation] in some fashion, though we must be in no doubt that they are not at all like them, but very, very dissimilar [ibid., 4:27].
Augustine, you say?