Is it rational to be religious? How much evidence do you need before deciding to act on a belief? If your religious beliefs are tightly bound up with your particular experiences and upbringing, doesn’t that undermine their reliability? In his new book, A Guide for the Jewish Undecided: A philosopher makes the case for Orthodox Judaism, Samuel Lebons argues that Jewish faith and practice can be firmly grounded in philosophy, science and decision theory alongside tradition. In conversation with fellow rabbi and author Raphael Zarum.