For who could better describe the eye than God, Who made it? But as it is clearer than the day that God has left a good deal to our own efforts ... we should really follow in these things the thread of nature, by which first principles, reason and daily experience lead us. Therefore, He prompts the minds of great men to inquire into the nature which He created, and He furthers and conducts their studies. These things must be enough to us, and from Holy Scripture we should seek in the first place only those things which are necessary to salvation.