The term “inherent vice” can be found on property insurance policies eliminating coverage for loss “caused by a quality in property that causes it to damage or destroy itself.” In other words, if the chocolate you’re shipping melts, you’re out of luck.

The new film from director Paul Thomas Anderson not only borrows the term as a title, but also the spirit. A complex stoner detective story, the movie’s characters are a doomed lot, debasing themselves with their own behavior. The result is a story of damaged personalities that requires a roadmap to navigate.

Joaquin Phoenix, is Larry “Doc” Sportello, a shaggy haired hippie detective in 1970 Los Angeles. Perpetually stoned he sees the world through a fog, and writes things like, “Paranoia Alert!” and “Not hallucinating” in his red detective’s notebook. When his ex-girlfriend Shasta (Katherine Waterston) asks him to investigate a plot to have her wealthy, married lover committed to a mental health facility, Doc is sucked into a complicated web of deceit involving a neurotic LA cop named Bigfoot (josh Brolin), a snitch (Owen Wilson), a drug crazed dentist (Martin Short), a drug syndicated called the Golden Fang and a man with a swastika tattooed on his face (Keith Jardine).

“Inherent Vice” plays like a brainier Cheech and Chong movie. The rambling story, that makes the work of Alaskan Native storytelling seem linear, sometimes gets lost in a cloud of pot smoke, and is occasionally almost incomprehensible, but never less than compelling. The actors, doing very high-level work, cut through the confusing murk of the plot, putting a human face on the twists and turns of the tale.

It’s been suggested that the mutton-chopped Phoenix based his performance on Leslie Nielsen’s work with the Zucker Brothers. That means playing it straight, or as straight as a stoner can be played. His hard-boiled lingo and natural PI ability are not played for laughs, but every now and again a measure of slapstick works its way into the performance; an unexpected yelp or an eager lunge at a table full of white powder. It’s an audacious performance that rides the line between serious and ridiculous without ever swaying too far one way or the other.

Your appreciation of Phoenix’s work, or at least the essence of the work, will relate directly to your enjoyment of “Inherent Vice.” The wonky tone, spread throughout the movie’s 148 minute running time, feels like an extended joke the audience isn’t always in on. When it works, it hums along, like a strange but enjoyable dream. When it doesn’t, it’s nightmarishly incoherent.