Saint Paul is a figure of great interest not only to biblical scholars and theologians but also to continental philosophers. Heidegger wrote a commentary on Paul. Badiou, Zizek, Agamben and others are fascinated by him. Simon Critchley was in London yesterday to explore one facet of Paul in particular, his faith.

Critchley explored how Paul is a dangerous figure, for the spirit of Paul is the spirit of reformation. Even Nietzsche perversely admired him, for Paul achieved a transvaluation of all values. Paul is no stabilizing figure, as if he were the founder of that edifice called Christianity. That's just to misread him, Critchley said, for Paul never talks about being Christian, but rather about being in Christ, part of a community that is awaiting the end times, part of a community that is the forerunner of that which is to come.

Paul's power is found in his powerlessness. He has become, literally, the shit of the world. But that slavery is the source of his strength, for it opens up radically new possibilities: only those who have lost everything have everything to gain, only those who have died to the old can be alive to the new. For Critchley - who is currently working on a book about 'faith for the faithless' - Paul's faith is declarative, an act that itself brings something into being. Faith is, therefore, not about belief but is rather a struggle to live according to the infinite demand of the future. Faith is like a pledge. The truth to which it bears witness is better thought of as troth. And it is love that drives that commitment not reason for, as Paul says, faith works through love.

Now, there is a heresy that lurks close to this delight in Pauline newness, the dualist heresy of Marcion who believed the old must be discarded in favour of the new - the Old Testament, in particular, with its old God, law and biopolitics. Only then can the vital spirit of the new be lived. The law kills but the spirit gives life. This Marcionism is implicit in many of the contemporary continental philosophers who are drawn to Paul, though Critchley resisted it because, he said, Marcion is ultimately wrong. We must live in the dialectic between law and life, old and new. That's not just the way the world is, but is also the source of the strife that defines us as human beings. It's our conscience - that open wound, Freud said, which will not heal but which makes us human.

John Millbank was present to respond to Critchley, and as he spoke, I understood one reason why theologians welcome the philosophers' interest: the theologians know Paul better than the philosophers do! Millbank welcomed much of what Critchley had to say, not least his rejection of Marcionism - though Millbank pointed out that if for Critchley the tragic mess of the world is the first and last word in what makes us human, for Christians the tragic mess is not the last word, for they have the hope of grace to lift them out of sin. Critchley seemed genuinely moved by the weight of sin that bore down upon him.

Millbank also drew back from the concept of faith as pure performance, observing that this made Paul out to be some extraordinarily hip artist, when in truth, he was a believer. What Millbank suspects the philosophers have failed to appreciate is that doctrine is not the Christian equivalent of deadening law, but rather that doctrine operates in an essentially negative mode: it refuses positions not advocates positions of its own, and so keeps the mystery open - the dialectic of the human and divine.

Finally, Millbank claimed back the dangerous Paul for the established church for he is not just a reforming spirit but also a spirit who builds community: his letters contain instructions for building communities as well as resisting empires. In fact, Millbank suggested, Paul was introducing a kind of democratized mystical community - a way of life that collapses the cosmic, the political and the philosophical; an amalgam of Greek and Jewish religious life, radicalised in Christ.

The other day, a friend of mine sent me a quote from Cicero, in which Cicero spoke of the Eleusian mysteries. After the initiation, Cicero wrote, 'We have been given a reason not only to live in joy but also to die with better hope.' My friend liked the spare scansion of the translation, as it sounds like one of Cranmer's collects. Perhaps Paul liked the Cicero too.

(Image: Rembrandt's Apostle Paul)