Usually, even a non-Christian knows something about the earth, the heavens, and the other elements of this world, about the motion and orbit of the stars and even their size and relative positions, about the predictable eclipses of the sun and moon, the cycles of the years and the seasons, about the kinds of animals, shrubs, stones, and so forth, and this knowledge he holds as certain from reason and experience.
Now it is a disgraceful and dangerous thing for an infidel to hear a Christian, presumably giving the meaning of Holy Scripture, talking nonsense on these topics; and we should take all means to prevent such an embarrassing situation, in which people show up vast ignorance in a Christian and laugh it to scorn.
The Literal Meaning of Genesis; 1.19.39, Trans., John Hammond Taylor, Ancient Christian Writers: The Works of the Fathers in Translation, ed. Johannes Quaasten et al., vols. 41-42 (Newman Press: 1982), 41:42-43.