Mick Gordon was once the hottest boy on the block, a galvanising artistic director of the Gate, Notting Hill, singled out by Peter Brook for special attention, hauled in by Trevor Nunn to brighten up his middle-aged National Theatre and even called into service by Peter Hall for a stint on Tantalus. Then he disappeared.

Now here he is back with his self-founded new company, On Theatre, and the third in a series of theatrical experiments that started at the Gate with On Death and On Love. On Ego, though, goes further than either.

Part lecture, part love story and poignant drama of a woman dying of a brain tumour, it attempts to encompass every other intellectual strand in between as a teasing sci-fi meditation on, amongst other things, the new art of teleporting, or Time Travel, by any other name. Only trouble is, what do you do when something goes wrong and you end up being duplicated, one of you in one place, one in another – in other words, cloned?

But it isn’t quite that, either. On Ego is about duplication only to the extent that it relates to identity. What makes us unique? Do we have a soul? You might think all those feelings, thoughts and daily commands from our ‘inner voice’ create what we like to call `us'. But Gordon and his co-writer, neuropsychologist Paul Broks, insist we are nothing more than a story, produced by a hundred billion neutrons. In other words, we are simply mechanical rather than a bundle of influences normally ascribed to the creation of the personality.

For those of us who've grown up with the latter idea (and, by extension the imperative of free-will and self-determination), Gordon and Broks’ thesis comes as a shock. Nor was I completely persuaded by Gordon's attempt to theatricalise Broks' thesis (On Ego is inspired by Broks' much admired first novel, Into the Silent Land), with its interplay of lecturing alongside Love Story meets Dr Who.

But Gordon, taking his cue from his mentor's earlier experiments with brain-matter (Brook's The Man Who Mistook His Wife for a Hat) directs with singular simplicity whilst Elliot Levey as Alex, the young lecturer transported beyond himself, and Kate Miles as his bright, interior designer wife disintegrating before us, have an unaffected glow. Anything, too, that boasts Robin Soans (as Alex's only faintly crazed professor father-in-law) rates in my book.

A broken-backed beast but a worthwhile, sensitive one.

- Carole Woddis