A year ago On Ego, the first "theatrical essay" from director Mick Gordon's company On Theatre, was a brilliant enactment of issues of identity in a relatively ordinary human context. Alas, its successor has only a fraction of its dramatic or even intellectual verve, despite being co-authored by philosoper A.C. Grayling. One would think that Grayling would have given the atheistical position a more sympathetic personification than university don Grace, who inveighs against religious belief with all the fervour and slightly less than the compassion of a Richard Dawkins. When her son Tom announces that he is giving up law to train as a priest, Grace's excoriations continue beyond the lecture theatre to the kitchen table. Yes, once you've set up a lecturer and a barrister-turning-priest as your antagonists, pretty much all you can make them do is talk at each other a lot.

Gordon and Grayling try to disguise this as a family drama by including Grace's husband Tony, a secular Jew, and Tom's pregnant girlfriend Ruth, an atheist of Hindu heritage, but these two don't add much sidelight. Having interviewed a range of people from Dawkins to the Archbishop of Canterbury via Don Cupitt, the writers also attempt to open up matters by having Tom argue that he is striving for "better religion", but no examples are forthcoming; they don't, for instance, seem to conceive of the possibility of a real religion based on evidence rather than faith, such as modern, non-table-tapping Spiritualism claims to be (I write as a former adherent who was introduced to that church by a family of scientists). Despite the further additions of an imaginary brain-stimulus machine to simulate "the religious experience", a non-linear scene chronology and the death of one of the main characters, the stage picture keeps washing out into black versus white. Gemma Jones fails to find much compassion behind Grace's stridency until a penultimate scene designed to do just that; Elliot Levey never conveys the "reasonable doubt" which leads Tom to change his life path. My star rating may be on the harsh side, but I will be far from alone in my deep disappointment that such a potentially pioneering approach has (I hope, temporarily) run into a rut.

Written for the Financial Times.