C.S. Lewis quote and the expression "You can't cheat an honest man"?

Question

Two questions:

1. Did C.S. Lewis ever say or write something like "We can expect it [theology] to be as complicated as physics"? I read the quote on one website but I cannot find it anywhere else.

2. What does the expression "You can't cheat an honest man" mean? I read this a while ago in one of Terry Pratchett's books. It was actually "You can't fool an honest man" but I've heard it more often as "You can't cheat an honest man." I'm having a hard time making sense out of this phrase. Can someone explain it, please?

Thanks!

Answer 1

1. I have never heard that C.S. Lewis quote before, now that doesn't mean he didn't say it.

2. You can't cheat an honest man is really a phrase that means an honest man would not get himself into a situation in which he can be cheated. He holds himself to a higher regard and when an offer may arose that has questionable circumstances, he walks away. It is the same as in you can't fool an honest man. The origin of these two almost identical quotes traces back to when gypsies used three cups with a stone under one of them and you had to pay money to guess which cup the rock is under. It was said back then that the honest man would walk away, while those in need would stay and play.