That’s not really how he himself describes it. His wife became a Christian and after going to church with her he wanted to investigate the backgrounds - he didn’t want to disprove Christianity and was quite open-minded instead:

She invited me to a church, where I heard the Gospel explained in a way I could understand it. While I didn’t believe it, I realized that if it were true, it would have big implications for my life. So I decided to use my journalism experience and legal expertise (at the time, I was legal editor of The Chicago Tribune) to investigate whether there was any credibility to Christianity or any other faith system.