“I not only confess, but I swear, that as many times as I have read it, which day and night are more than a thousand, my wonder and astonishment have always increased, seeming every time to find therein new beauties and new instruction, and consequently new difficulties.”

This subject is also discussed in part by Thomas Aquinas, Summa Theologica , I Quaest. CXIX , De propagations hominis quantum ad corpus .