The power of doubt ...

... Plato's Dialogues, part 2: Who was Plato's Socrates?

... the genius of Plato's Socrates was to embrace ordinary human uncertainty and doubt, and fashion it into a flourishing way of life. He recognised that to be human is typically to be ignorant, though unlike other animals, the human creature can become conscious of his or her lack. And contrary to what the doctrinaire believe, therein lies something immensely valuable. A developed sense of what lies beyond us powers human innovation and creativity. A disciplined desire to reach out for more is the refinement of love. A subtle understanding of the limits of knowledge is the beginning of wisdom.

Mark calls himself an agnostic. But his agnosticism has nothing to do with not being able to make up your mind. As elaborated in After Atheism, it is a method of living apophatically, which seems to me is also the way of faith, the sort of faith that enables one to walk in the valley of the shadow of death and fear no evil.