The Enchiridion 9
9 What We are to Believe. In Regard to Nature It is Not Necessary for the Christian to Know More Than that the Goodness of the Creator is the Cause of All Things PL 40, 235
When, then, the question is asked what we are to believe in regard to religion, it is not necessary to probe into the nature of things, as was done by those whom the Greeks call physici; nor need we be in alarm lest the Christian should be ignorant of the force and number of the elements,—the motion, and order, and eclipses of the heavenly bodies; the form of the heavens; the species and the natures of animals, plants, stones, fountains, rivers, mountains; about chronology and distances; the signs of coming storms; and a thousand other things which those philosophers either have found out, or think they have found out. For even these men themselves, endowed though they are with so much genius, burning with zeal, abounding in leisure, tracking some things by the aid of human conjecture, searching into others with the aids of history and experience, have not found out all things; and even their boasted discoveries are oftener mere guesses than certain knowledge. It is enough for the Christian to believe that the only cause of all created things, whether heavenly or earthly, whether visible or invisible, is the goodness of the Creator the one true God; and that nothing exists but Himself that does not derive its existence from Him; and that He is the Trinity—to wit, the Father, and the Son begotten of the Father, and the Holy Spirit proceeding from the same Father, but one and the same Spirit of Father and Son.
Quid credendum, servato Symboli ordine, deinceps explicatur. Non opus esse curiosa inquisitione rerum naturalium. Christiano sufficere si credat a summe bona Trinitate omnia creata esse, eaque bona. Cum ergo quaeritur quid credendum sit quod ad religionem pertineat, non rerum natura ita rimanda est, quemadmodum ab eis quos physicos Graeci vocant: nec metuendum est, ne aliquid de vi et numero elementorum, de motu atque ordine et defectibus siderum, de figura coeli, de generibus et naturis animalium, fruticum, lapidum, fontium, fluminum, montium, de spatiis locorum et temporum, de signis imminentium tempestatum, et alia sexcenta de iis rebus quas illi vel invenerunt vel invenisse se existimant, christianus ignoret; quia nec ipsi omnia repererunt tanto excellentes ingenio, flagrantes studio, abundantes otio, et quaedam humana conjectura investigantes, quaedam vero historica experientia perscrutantes, et in eis quae se invenisse gloriantur, plura opinantes potius quam scientes. Satis est christiano rerum creatarum causam, sive coelestium sive terrestrium, sive visibilium sive invisibilium, non nisi bonitatem credere Creatoris, qui est Deus unus et verus; nullamque esse naturam quae non aut ipse sit, aut ab ipso: eumque esse Trinitatem, Patrem scilicet, et Filium a Patre genitum, et Spiritum sanctum ab eodem Patre procedentem, sed unum eumdemque Spiritum Patris et Filii.