The recent passing of Oscar winning actress Diane Keaton is reason enough to revisit one of her few directing credits, the lone documentary on her resume.

“Heaven,” which she completed and Island Pictures released back in 1987, when Keaton was at her Hollywood peak, is a playful, dizzy reflection of the woman herself — quirky and curious and fun, with flashes of insight and wry delight.

She made a film on a subject about which no one knows anything and thus everyone is an expert. So there are no Archbishops or Popes or Dalai Lamas weighing in here.

In a room artfully lit with architecture-mimicking shadows (in Palm Springs, apparently) Keaton questions some Protestant preachers, yes, and a rabbi is in the credits. There are Catholics in the ranks, but nobody in a collar appears on camera. Instead, she serves up samples of theologians and pastors from TV appearances, many of them vehement in their certitude.

Why question those who’re sure they have answers — “The New Jerusalem is 5000 times the height of New York,” the Bible says, according to one televangelist — when you can get family members, friends, hippies and hipsters, questioners and the curious, Salvation Army footsoldiers, Boy Scouts and boxing promoter Don King to speak on the great imponderables?

“Do you believe in heaven?” “Are you afraid to die?” “Can heaven be here on Earth?”

Every “expert,” even the questioning ones, picks a hill to die on.

“God is NOT a woman,” a bearded evangelist insists. “Heaven is an orgasm” a beau says in front of his giggling, blushing intended. “People never look in the sky,” one very old little old lady suggests. “There are SIGNS in the sky, Diane!”

Those “certain” they know can be angry or exasperated, and self-revealing in other ways. Belief has never been summed up better than by the lay preacher who says this.

“God likes to reward ignorance for ignorance’s sake.” The dumber you are, the more fervently you believe?

That was kind of the point in the Falwellian Reaganarchy of 1987 — mockery. In finding so many disparate points of view, from the devout breaking into song and quoting Scripture to the questioning demanding “proof” and contending with the circular logic of just whom the burden of proof lies with — believers or those who doubt — Keaton digs into layers of sometimes amusing superstition and belief and prods those who admit not having any answers beyond hopes and fantasies.

Nobody is identified on camera, putting every “expert” on a level playing field.

Working with editor Paul Barnes, Keaton excerpts decades of cinematic visions of the afterlife — “Green Pastures,” Astaire and Rogers “in heaven…dancing cheek to cheek” in “Top Hat,” David Niven and others riding that “Stairway to Heaven” and Spencer Tracy’s “A Guy Named Joe” wading across a fog-floored soundstage into the afterlife.

By the third act, the sense of mocking those with simple beliefs, pro or con, and the bickering recedes into the background and the film turns poignant, an effect enhanced by the fact that Keaton herself just died. That seems like the perfect moment for Sam Cooke to sing his Gospel hit, “That’s Heaven to Me.” And it still is.

Rating: PG-13, profanity, homophobic slurs

Cast: Don King, Victoria Sellers, Kenny Ostin, Abram Christ, Jacob Christ, Pastor L.D. Shaw, Evangelist Robert Hanan, Ruben Ben David, Pinkietessa Braithwaite, many others

Credits: Directed by Diane Keaton. An Island Pictures release re-issued by Lightyear.

Running time: 1:19