It is, of course, quite true that God will not love you any the less, or have less use for you, if you happen to have been born with a very second-rate brain. He has room for people with very little sense, but He wants every one to use what sense they have. … God is no fonder of intellectual slackers than of any other slackers. If you are thinking of becoming a Christian, I warn you, you are embarking on something which is going to take the whole of you, brains and all.
The most common view of morality in our culture is probably the one that says we can do whatever we like as long as we don’t hurt anyone else. This is, of course, accurate as far as it goes. If you are going to engage in some kind of destructive behavior, the rest of us would be happiest if you only harm yourself. But is that the whole story?