On Ego, Soho Theatre, London

Beam me up! Erm, I said...

A smug clinical lecturer, Elliot Levey's Alex teaches us about bundle theory which, as a materialist, he upholds, opposing the more mystical ego theory. He emphasises we're just flesh, bone, brain and linked neurons, with our life experiences - feelings thoughts and memories - scattered through different cerebral zones. There is no ghost in the machine, no ethereal ego or "I". That's an illusion.

Then Alex sets out to prove his point. His colleague and father-in-law, Derek, is to teleport him, Star Trek-style, so he is flawlessly reproduced at a restaurant to celebrate his wedding anniversary with his wife, Alice. However Alex is accidentally duplicated, surviving in his original form. Meanwhile, his spouse, with a growing brain tumour, insists the husband visiting her in hospital is an imposter.

On Ego's central theses are interesting. There are dramatic ambiguities regarding who's who and what they might be imagining. And Kate Miles Alice is poignant, undergoing her own distressing personality changes. But Robin Soams' Derek shouts his lines, and Levey's Alex only contrives to be mildly irritating. The couple's schmaltzy anniversary games and the self-conscious allusions to Hamlet, including a brain held up like Yorick's skull, are toe-curling.

Gordon vanished off the scene for a while, after orchestrating the NT's Loft Season. It's good to see him rematerialise, but his new company, On Theatre, hasn't exactly got off to a flying start.

To 7 January, 020 7478 0100