This play was inspired by the international bestseller Sapiens by the gay Israeli intellectual Haran. To produce the history of humanity on stage on any one night would have been very daunting, and might have led to the kind of indigestible evening I have known on occasions in Edinburgh. This performance is richly and rewardingly digestible.

It focuses down on the figure of Jacob Bronowski, who produced a series called The Ascent of Man several decades ago, which purported to show a continuous line of progress and development in human affairs. However, in 1949 he installed a locked room in his house. What secrets does it contain? Do they undermine the thesis of his series and of his philosophical approach?

Through the medium of a woman who is researching just this area happening to arrange an online date with Bronowski’s grandson and thus gaining access to the house with the locked room we find ourselves on an investigative chase after the truth. Cue flashbacks to Bronowski being persuaded to become involved in wartime research which flatters his mathematical abilities and will help defeat the Nazis – but at what cost? Meanwhile Bronowski’s colleague learns the cost of aerial warfare when he loses his long term male partner. But – does he learn? Do humans learn?

This is a thought-provoking play, with the different elements well integrated. The acting is not always crisp enough to be engrossing, and there is a lack of tension in parts of the play. There comes a point where you can very much see where things are going. Yet it is very well worth experiencing, and discussing afterwards.

Tony Challis