Why bother to praise mathematics when you claim as Alain Badiou does that philosophy is first & foremost a metaphysics of happiness or else it s not worth an hour of trouble? What possible relationship can there be between mathematics & happiness? That is precisely the issue at stake in this dialogue which serves as a very accessible introduction to what mathematics is & an exploration of the crucial influence it has always exerted on the greatest philosophers Far from the thankless pointless exercises they are often thought to be mathematics & logic are indispensable guides to ridding ourselves of dominant opinions & making possible an access to truths or to a human experience of the utmost value That is why mathematics may well be the shortest path to the true life which when it exists is characterized by an incomparable happiness