Dimpled chads, crashing stocks, anthrax, smallpox, and Saddam. All that and we’re still wondering what’s wrong with Tony Soprano. As the fans of the hit HBO series will tell you, The Sopranos began in 1999 when Tony, a mob boss, blacked out beside his swimming pool in suburban New Jersey. He promptly hired a therapist to help him deal with a set of psychological issues, including the panic attacks that now and then dropped him like a stone. Four years and 52 episodes later, Dr. Jennifer Melfi has dredged up all there is to know about her thuggish but complicated client, his wife and kids, and his dealings in what he likes to call “waste management.” The only mystery left is what’s ailing him.

Melfi’s real-life peers have called her sessions with Tony the best portrayal of psychotherapy ever seen in the popular media, and the show has apparently led a lot of men to try it. Among therapists, there’s been no end to the discussion about the series, in print and online. When they bring up Melfi’s failure to get at the root of Tony’s problems, they blame everything from her short skirts to her various missteps (which nicely complicate the story) to the chance that her client is a psychopath who can’t be cured. Very few have suggested that the problem may be a blind spot shared by her entire profession.

Tony fired his psychiatrist at the end of last season, but she’s almost certain to return for the fifth and perhaps last chapter in the Soprano saga. Their exchange goes back to the first episode, when Tony tells Melfi that his attacks began when the ducks that were living in his yard decided to fly away. He explains how happy he was when “wild creatures” came to his pool and had their babies. “I was sad to see them go,” he adds, and “I’m afraid I’m going to lose my family.” Week after week, Melfi explores every possible thing those birds could symbolize, from issues with Mom and Dad to his own teenage children leaving home. She consults the Diagnostic and Statistical Manual of Mental Disorders—the DSM—and even recites from the profession’s handbook in the dogmatic drone of a true believer. She never considers that sometimes a duck is just a duck.

In the volumes that have been written about The Sopranos, there’s hardly a word about how its natural backdrop, the duck’s world, or what remains of it today, is such a mess. Nevertheless, a case can be made that our troubled relationship with nature is one of the show’s ongoing themes. Creator David Chase and his colleagues usually touch on the subject in a fleeting and witty way, with a character’s offhand remark or the camera’s deadpan stare at some ugly urban artifact; but it’s often there, and has been from the start. That all of us seem to look right past it says a lot about how conditioned we are to take the degraded state of the natural world for granted.