Rather than framing moral philosophy as just another form of epistemology (how can we know what to do?), Iris Murdoch was asking a more classical question: “How can we make ourselves morally better?” she asks. “These are the questions the philosopher should try to answer.”
The question of trust, of giving ourselves to something outside ourselves, is quite fundamental. It goes to the nature of who we are as human beings. One might pose the question this way: Are we clams or clovers?