The intense—even fierce—seriousness of the gifted clown is one of show biz’s more time-honored rumors. It’s enshrined in the comedian’s language of annihilation, where comedy “slaughters ’em,” “lays ’em in the aisles,” or makes them “bust a gut.” Audiences are expected to laugh ’til it hurts, as if laughter were an inadequate response to what is truly funny.

So it’s appropriate that writer/director Peter Chelsom begins Funny Bones, his darkly uproarious comedy about the nature of comedy, with an encounter between a man and a ship’s propeller that leaves a pair of disconnected feet bobbing off the coast of Blackpool, England. The feet will later figure in a plot that involves six wooden eggs, police corruption, an alleged eternal-youth powder, a gaggle of aging vaudevillians, a family inheritance that has little to do with money, and a man who refuses to come down from his perch atop Blackpool’s beachside tower.

But first, Chelsom cuts to Las Vegas, where a deeply unfunny comedian named Tommy Fawkes (Oliver Platt) is about to make his debut. For years, Tommy has lived miserably in the shadow of his father, George “Mr. Originality” Fawkes, a beloved funnyman (played in neat self-caricature by Jerry Lewis) whose comedic approach is pretty much inimitable. Alas, that hasn’t kept Tommy from aping it slavishly. On this particular evening, Dad has booked a ringside table, and as he makes his way to it, doing shtick and acknowledging his fans with broad smiles, it’s clear he won’t be able to help upstaging his son. The film will later make a distinction between comics who are funny and those who merely tell funny, but there’s never any question that Tommy doesn’t fall into either camp. Mopping flop-sweat from his brow, he knows the crowd is going to hate him, and figures he has nothing to lose by taking his act over the edge. With Dad looking morosely on, he bombs spectacularly, then skips town to search for a new path to funniness.

That search takes him to Blackpool, his childhood home and a onetime mecca for comedians, where his offer to buy the rights to original physical-comedy material brings out an avalanche of ancient comics with offbeat skits and sketches. Auditioning all manner of bizarre acts, from burly dancers in tutus to mimetic vaudeville comics, Tommy comes into contact with the Parker family—septuagenarian brothers Thomas and Bruno (revered Brit clowns George Carl and Freddie Davies); Katie (Leslie Caron), the still-glamorous singer who was once married to Thomas; and Katie’s uneducated, possibly insane circus entertainer son Jack (Lee Evans), to whom the phrase “knock ’em dead” isn’t the least bit euphemistic. When Tommy discovers that the elder Parkers once worked with his father, he’s a hair’s breadth away from a secret that explains both his father’s success and his own misery and failure.

Chelsom, whose direction of Hear My Song turned that offbeat show-biz comedy about an expatriate Irish tenor into a crowd-pleasing hit, approaches this new story in much the same spirit. But the material is strong enough that it comes across not merely as a compelling narrative with Oedipal undertones, but also as a treatise on how comedy works. Chelsom’s script nicely articulates the distinction between people who are funny to their cores—who have, in the film’s parlance, “funny bones”—and those who have simply learned the skill of telling jokes effectively. But the director/writer is actually exploring a more interesting dichotomy: that between comedy that prompts laughter and comedy that prompts something closer to fear. The latter—as has been suggested in works as disparate as Trevor Griffith’s comedy-classroom play Comedians, Bob Fosse’s Lenny Bruce biopic Lenny, and Martin Scorsese’s stalker epic The King of Comedy (which coincidentally also starred Lewis)—is where true brilliance lies. Squirm-inducing jokes dig deeper into the psyche; the laughter they seek is as bruising as it is cathartic.

Groucho Marx used to distinguish between amateur and professional comedians by saying that an amateur thinks it’s funny to dress a stuntman as an old lady, place him in a wheelchair, and send the wheelchair rolling down a slope toward a brick wall. “For a pro,” Groucho said, “it’s got to be a real old lady.” In the finale to Funny Bones, Chelsom works a nifty variation on that premise using a circus sway-pole, thereby giving an affecting but sentimental tale a gratifyingly chilling climax.

His performers are all well chosen. As the talentless Tommy Fawkes, Platt sweats failure so furiously he seems to be trying to shed his skin. And stand-up comic Evans makes a fine film debut by turning the untutored Jack into Tommy’s diametric opposite: an intuitively brilliant, erratic, terrifying comedian who is simultaneously threatening and endearing. You figure Lewis could do the onstage George Fawkes in his sleep, twitches and comic timing being his well-nigh exclusive province these days, but his offstage shtick turns out to be just as effective, blending telethon unctuousness with a healthy dose of indignation. Though heftier than she was half a century ago opposite Gene Kelly in An American in Paris, Caron is still radiant and classy. And nearly all the old-timers who back them up—Carl and Davies doing time-honored vaudeville routines, Harold Nicholas (of the Nicholas Brothers) as a Vegas hoofer, and virtually every Brit music-hall performer who can still walk—are blessed with bones that are undeniably (if a bit brittlely) funny.