by Natalie Bennett

On Religion is billed as “an exploration of the most controversial subject of the moment”, and it is a collaboration between the philosopher AC Grayling and the writer-director Mick Gordon, who was also involved with the somewhat similar On Ego a year ago.

There’s the same blend of human drama and philosophical exposition, with perhaps a greater percentage of the former than marked Ego, and the slick production values we’ve come to expect of the Soho Theatre. Yet, somehow, it was less satisfying.

With the balance trending more towards drama and less towards thought, we are presented with a family at the point of explosion. Grace (a fine, powerful performance from Gemma Jones) is an ageing but popular academic whose made her career out of what’s generally called atheism, although she’s so hardline that she she refuses to use a word with “theism” in it.

She goes predictably ballistic when her lawyer son Tom (a super-cuddly and engaging Elliot Levey) suddenly announces that he wants to become a minister. In the middle between them are her patient, long-suffering husband Tom (Pip Donaghy) and Tom’s girlfriend Ruth (Priyanga Burford).

The problem is that both sides are shown, despite their outbreaks of apparently rational argument, to be emotionally attached to their positions, indeed it seems they are shaped and maintained simply by that emotion, the arguments being pure rationalisation. Some of the most powerful scenes are those in which Grace delivers her lectures – she’s excellent on the 18th-century originator of the ‘Blind Watchmaker’ theory, William Paley.

The family conflict, and the internal pain in the characters that follows a rather predictable twist — Tom is killed in a terrorist bombing — by contrast comes over as more soap opera than controlled drama. The sobbing all gets a bit much – and might not be what you expect from a “philosophical” play.

On Religion continues at the Soho Theatre until January 6. (With online booking.) Other views: Kate Bassett in the the Independent and Sam Marlowe in The Times.