What language can attain to the marvels of the Creator?  What ear could understand them?  And what time would be sufficient to relate them?  Let us say, then, with the prophet, “O Lord, how manifold are thy works! in wisdom hast thou made them all.” Ps. civ. 24.  We shall not be able to say in self-justification, that we have learnt useful knowledge in books, since the untaught law of nature makes us choose that which is advantageous to us.  Do you know what good you ought to do your neighbour?  The good that you expect from him yourself.  Do you know what is evil?  That which you would not wish another to do to you.  Neither botanical researches nor the experience of simples have made animals discover those which are useful to them; but each knows naturally what is salutary and marvellously appropriates what suits its nature.