James Hebert - San Diego Union-Tribune

D.W. Jacobs and Francis Gercke. Photo: Randy Rovang

The wisdom of cloning comes off looking extremely iffy in "A Number." And yet in spite of itself, the work makes one good argument for the practice: Cloning theatergoers might give them a fighting chance to catch all the ideas pinging around in this play.

Caryl Churchill's compact, unsettling ethical meditation, now in its San Diego premiere at Cygnet Theatre, is like a cell that's been stripped down to its dense, pulsating nucleus.

Even the dialogue can seem distilled to DNA; conversations are clipped and cryptic, with meanings often misunderstood until the characters refine and re-combine their words.

The 2002 work by the British writer, whose '82 play, "Top Girls," has just made it to Broadway, is short (just one hour) and calls for only two actors. At Cygnet, D.W. Jacobs plays the father figure, Salter; Francis Gercke portrays three of his "sons," though the question of which is the original becomes less clear (and less relevant) as the play proceeds.

Churchill is clearly not so interested in cloning itself as in using it as a device to dig into such ideas as the meanings and mutability of identity and memory. And, more provocatively, the specter of eugenics.

One of the play's most fascinating aspects is that with the arrival of each new version of the son, we also see a fresh iteration of Salter.

The sons, now ages 35-40, and all sharing identical genes, have turned out starkly different from each other. Part of the play's unfolding mystery is whether Salter is merely reacting to each of their personalities, or whether his shifting attitudes toward them are a hint to how they became who they are in the first place.

As the play opens, Salter seems a concerned and confused dad. He's reeling from the news just delivered by his affectionate but uncomprehending son that there are "a number" of copies of him walking around.

The next son to arrive is agitated and dangerous, a black-clad menace who demands that Salter tell him what happened when he was a boy.

The last lad is almost absurdly well-adjusted, wearing his country-club get-up like a badge of happy rapture. He's so spectacularly non-introspective that when asked to reveal just one unique personal quality, he blathers on about the shape of his wife's ears.

Jacobs' unassuming, measured portrayal of Salter makes later revelations about his involvement in the cloning (and the reasons behind it) all the more chilling. It's a performance that slowly burrows under the skin.

And Gercke's transitions between his characters are astounding, with every element – even subtleties of voice and movement - recalibrated to the nervous system of each new "son." When (as the violent Bernard) he suddenly grabs an orange – pulled, tellingly, from a bowl of identical fruit - and obliterates it against a wall, the whole play rocks on its foundation.

Churchill's clipped dialogue takes some getting used to, and on opening night it felt a bit out of phase at times. Director Esther Emery, though, imbues the staging with a great sense of dynamics; a few well-placed silences create some of the most gripping moments.

George Yé's haunting sound design meshes well with Matthew Novotny's gentle swirl of lights, behind the spare set by Jungah Han. It's all of a piece with the play's sense of shifting moralities – its evocation of a mindset where humans are fair game for do-overs, and as dispensable as a bit of buggy software.

"You called them things," one son says to Salter of his unnumbered brothers. "I think you'll find they're people."

He shouldn't be so sure.