“Orthodoxy is the wide open field within which successful breeding can take place. If one maintains that Jesus was an eater of magic mushrooms or a Martian, then this will not make for fertility. There is not enough in common for there to be intercourse in any sense. How different can two believers be for the encounter to be fertile? This is a complex question which we do not need to explore here. Of course ultimately we must share orthodoxy, but this is not to narrow the scope of the conversation; it is to enter the broad terrain of the mystery, in which we are liberated from the tightness of ideology. It is a serious misuse of language to use the word 'orthodox' to mean conservative or, even worse, rigid. Orthodoxy does not lie in the unvarying and thoughtless repetition of received formulas. As Karl Rahner pointed out, that can be a form of heresy. Orthodoxy is speaking about our faith in ways that keep open the pilgrimage towards the mystery. Often it is hard to know immediately whether a new statement of belief is a new way of stating our faith or its betrayal. It takes time for us to tell.”