Word is that in the Borderlines Festival Inherent Vice has been the most walked-out-of film. Naturally I was intrigued, even heartened by this promise of excess or obscurity and two people bailed out of our viewing early on. Their reasons, however could hardly have been moral in nature: although there was seediness galore and no shortage of ‘sex references’ they left before the latter became actual rather than implied. Likewise any artistic objections, the plot lines still manageable at that point although they did continue to ramify. No, I suspect what drove the quitters to the exit was an inability to hear what the characters were saying. ‘They mumble so,’ my mother used to complain about American films, a comment I condescended to with my love of authenticity and whistle-clean tubes. The former remains but the latter are as furred as a kettle, the hard water of loud music probably to blame. The audiences at the festival have been roughly my age, a cloth-eared demographic ill-served by muttering. But most last the course, nostalgia trumping incomprehension. Slurred speech, muddled thinking: those were the days.

It follows that anything I say about the film comes with a disclaimer, things likely to have been missed or misheard. Blessed are the cheese-makers, after all. With that in mind, Inclement Dice tells the story of ‘Doc’ Sportello, a hippy private investigator on the trail of his former girlfriend, her big shot sugar daddy, a maybe-dead musician, a murdered biker, a Far Eastern drugs cartel, a semi-official hitman and what powers of reasoning survive in a dope-addled mind. His opposite number in the police, ‘Bigfoot’ Bjornsen helps, hinders, berates, confides, arrests and discharges as the ever-more unhinged mood takes him. He is Doc’s alter ego, a good man ruined not by drugs (although he is not averse) but by corruption in the force and the death of his partner, condoned if not connived at by the chain of command.

It is a world of sex parlours and spliffs, property deals and police brutality, louche dentists and lovely DAs, miniskirts and marijuana. Music, too although the film resists the temptation to fill the soundtrack (and spin-off CD) with a compilation of hits. Instead Jonny Greenwood’s score remains unobtrusive, which ought not to work but somehow does. The exceptions are two bursts from Neil Young whose spacey lyrics and adenoidal pitch have come to speak for the age of Woodstock and Altamont, his voice, like the moment itself, uncompromising yet flawed. The countertenor of the counter-culture.

In the lead role Joaquin Phoenix gives a master class in befuddled integrity, while as Bigfoot Josh Brolin seethes with malice and discontent. Above all, however Inhalant Mice confirms the status of Paul Thomas Anderson as a mould-breaking film maker not afraid to push boundaries or test his audience’s stamina. Adapting a Thomas Pynchon novel takes nerve and balls. Thanks to the book – but not entirely – there are numerous influences or echoes at work. Sportello is a hippy Sam Spade or Philip Marlowe, although Raymond Chandler would have got the job done in half the time. He is also Marlon Brando, sub-vocalising in The Godfather and Jeff Bridges in The Big Lebowski, except that given the date of Pynchon’s original it is hard to know who came first, the Doc or the Dude. Still Anderson’s vision is quirky and capacious enough to embrace all this source material while remaining resolutely his own. Who knows, he may even have invented a new genre: the pot-head procedural or CSI (Confused Stoner Investigates).