Every good work of art is about more than one thing, but Albee's infamous The Goat, or Who is Sylvia? is harder to get a bead on than most. The very premise is disorienting: This is a play, which debuted in 2002, about a man who falls in love with livestock, and it's not a farce. It is, however, darkly, darkly funny. And one way I've been thinking about it since seeing it this past weekend disturbs me particularly: The Goat explores how far a man will go to preserve the sense that he is Innocent.

By "innocent," I don't mean "not guilty." Albee's protagonist, a successful and happily married architect named Martin, technically admits his four-legged infidelity in scene one, and though he's keen to keep it a secret from his wife, Stevie, he never denies it. The virtuosic heart of the play -- it must consume a full third of the 110 intermissionless minutes -- is Martin's confrontation with Stevie after the truth is revealed.

Nobody writes arguments like the creator of Who's Afraid of Virginia Woolf? and this one, between two exceptionally smart characters played by two exceptional actors, rivets. ("I wish you were stupid," says Stevie at one point, and Martin returns the heart-crushing compliment.) Stephanie Mayer Staley's set -- the cinderblock-wall and the family's push-button lighting grid surrounding the artworks, the Lucite architect's models -- is a bunker full of fragility. Robin Walsh's turn as Stevie, alight with irony and betrayal, is at times nearly too painful to watch. 

But it's Martin, beautifully played by Tony Bingham, who haunts me most. He is Albee's Good Liberal, for all the right things: tolerance (though struggling with his son's homosexuality); the future (he's designing a "City of Tomorrow," or some such). Though he's always correcting people's language ("the goat whom you've been fucking"), he is nothing if not empathetic. One sequence of his argument with Stevie involves Martin's story about a bestiality therapy group he attended, the point of which story is to explain away people's intercourse with pigs (the man had done it since he was a farmboy) and geese (the man was very ugly) and German Shepherds (the woman had been repeatedly raped as a child).

When I interviewd director Rodger D. Henderson for a preview piece on the show, he emphasized the theme of whether our lives are about what we do, or what's it's thought that we do. It's a significant question in the play, but I'm more struck by Albee's emphasis on it being Martin's 50^th birthday; his forgetfulness; his childlike wonder in relating how he felt when he was with the goat; and even his repeated insistence that never once before, in more than two decades of marriage, had he even considered being unfaithful to Stevie. Wide-eyed and distracted, as Bingham plays him, he seems to argue that because his heart intended no malice -- was innocent -- he couldn't commit any. And that having an affair with a goat was right (or at least not wrong) because it felt right.

OK, Albee seems to be asking -- of his characters, himself, his audience -- what's not all right with you? What can't you justify to yourselves?

(The Goat continues at the Rep through Sun., Dec. 14.)