When I was a teenager, I wasn't a Christian, and I grew up before the sexual revolution. I grew up when it was still considered a matter of ethics to keep your virginity until you were married. When I was a young man, I heard an older boy talk about this thrilling experience he had sexually with a girl that lived up the street. My eyes were like saucers; I had never heard anything like this before. He said, "Try it. You'll like it."

So I did, and here's what happened: I came home, went upstairs to the bathroom, and threw up. I was so sick with guilt. But I learned very quickly how to sear my conscience, and I changed--not my behavior but my ethical standards. I adjusted my ethical standards downward to accommodate my behavior. And I'm not the only man who's ever done that. Most of our ethical theories we develop to excuse ourselves.