Might I begin with the personal remark that in the course of preparing this lecture for Blackfriars in Oxford, I was quite unable to prevent thoughts of Herbert McCabe’s absence here today from occupying my mind. You must forgive me if, though he is absent physically, you are able to identify his presence intellectually within the few thoughts I offer you today; for the inclination to give some expression to the conjunction of influences which some thirty years of debate with Herbert have visited upon me personally became, in the circumstances, irresistible. Back in the early nineteen-eighties Nicholas Lash and I published in quick succession monographs on the subject of Marxism and its relation to Christian theology. We agreed on much of a theological nature, disagreed sharply on how to read Marx, so Herbert, then in his second stint as editor of New Blackfriars, invited us each to review the work of the other, Nicholas first, me to follow. With characteristically wicked wit, Herbert entitled my reply to Nicholas’ review ‘Turner Responds to Lash’. Well, today I mark my indebtedness to Herbert by means of a lecture which I am happy to concede is, in a manner, a response to Herbert’s ‘lash’, and in some spirit of emulation, could I achieve it, of that fierce clarity and energy of thought which so characterised what Eamon Duffy called ‘his mighty soul’.