Jack's assertion is that there are benefits to having belief that make belief rational. That's a good point. My only problem with it is that it isn't the point we've been talking about for days. The fact that it is rational for Jack to have belief because non-belief is worse in his life does not mean that the tenets of the belief itself are rational on their own merits. In other words, the fact that belief in God improved Jack's life doesn't prove that God exists.