But there's a complication: According to Werner Heisenberg's uncertainty principle, increasing the accuracy of measurement of one observable quantity increases the uncertainty with which other quantities may be known. Indeed, the mere act of observation can affect what we're looking at.
This may not seem like fodder for gripping theater, but what if we're observing not subatomic particles, but human beings? In the 1920s, physicists like Heisenberg and his mentor Niels Bohr posited that the universe exists only as a series of approximations as interpreted by the observer. So can we look back on a conversation between two people and truly understand what passed between them? Well, we can surmise what happened by observing what took place after the conversation. And since we're dealing with people, we can, of course, ask them what they talked about--but their accounts may change, depending on who's asking, and depending on what they do and do not want to remember.
Michael Frayn's Copenhagen is a play about quantum physics blown up to a human scale. Frayn's script occasionally seems like a textbook with stage directions, but Arizona Theatre Company's production, directed by Stephen Wrentmore, does a remarkable job of mining words from the page and rendering them into that most fissionable material, emotion.
The play begins in the afterlife; in an icy wasteland designed by Scott Weldin, three figures try to understand what took place one autumn day in 1941 when Heisenberg came to occupied Copenhagen to chat with Bohr about--what? Heisenberg himself doesn't quite understand his motivation, although he has some dim, intuitive sense of it. Like good scientists, he, Bohr, and Bohr's wife, Margrethe, proceed to study the personalities in collision that day and the effects of the meeting, running the experiment again and again in their minds to support or disprove one hypothesis after another.
Fifteen years before, Heisenberg had lived in Copenhagen, studying and working with Bohr, a Nobel-winning physicist. Bohr, according to this play, regarded Heisenberg as a surrogate son, having lost one of his own in a boating accident, but the two men broke over professional differences. By 1941, Heisenberg was back in Germany, watched constantly by the Gestapo as he ran the nation's nuclear research program. Now he returns to Copenhagen to visit Bohr, who is himself under surveillance.
The Bohrs, particularly Margrethe, are reluctant to see Heisenberg again, not understanding why he, unlike most of Germany's other leading scientists, has stayed behind. They also fear that they'll appear to be collaborating with the occupying Nazis if they welcome Heisenberg. But after some initial tension, the two men are on splendid terms again--until a conversation on an abortive walk through the woods permanently ruptures their relationship.
Even Heisenberg isn't quite sure why he's come--the most difficult object for him to observe is himself--and, from the afterlife, his memory of the event is not reliable; Bohr's recollection is also suspect. To complicate matters further, Heisenberg can't speak frankly during his Copenhagen visit, with the Gestapo listening in.
Has Heisenberg arrived to advise the half-Jewish Bohr on which Germans in Denmark he can trust if things turn nasty? Has he come to pump Bohr for information on a possible American nuclear program? Has he come for technical advice on his own work? Or has he come to press Bohr to tell anyone who asks that, as he has long believed, you can't use fission to make a weapon? And if so, who, exactly, does Heisenberg want Bohr to discourage, and why?
Each of Frayn's characters is an overgrown subatomic particle. Niels Bohr (Ken Ruta) is a proton, a settled, positive force with unwittingly dangerous potential if he's split from his neutron, the stern, cautious Margrethe (Jeanne Paulsen). Heisenberg (Brian Dykstra) is an electron, wildly orbiting the others, conducting science with intuitive leaps rather than Bohr's plodding care.
Frayn burdens his script with too much inelegant expository dialog, and the bulk of Act 2 is a heated debate over theoretical physics. But Frayn mines the debate for excellent metaphors to apply to human nature and, specifically, to his three characters.
Ruta, Paulsen and Dykstra eschew theory and throw themselves into the applied science of acting with all the skill and passion their characters display. The men are given more opportunities for this. Ruta's Bohr is a fumbling, aging, plodding but brilliant man haunted by his son's death; Dykstra's Heisenberg is equally brilliant, but more impulsive and given to unintentionally insensitive remarks. Ruta has always been a master of the half-mournful, half-quizzical gaze, and uses it to great effect here. Dykstra's specialty in this play is an expectant, coaxing expression, as he waits in vain for Bohr to complete thoughts Heisenberg cannot utter.
Completing the production are Scott Weldin's stark set and Rick Paulsen's lighting, as restless and shadowy as the scientists' minds.