Mike Cahill, the writer-director of “Another Earth,” offers an even sillier follow-up with the pretentiously titled “I Origins,” which aims to say something profound about the emergence of human life but despite a stylish surface ends up a hopeless sci-fi muddle.

Michael Pitt, who usually plays zonked-out types, isn’t terribly convincing as Ian Gray, a biologist who’s been fascinated with eyes since he was a youngster; in fact, he’s been taking photos of them for years, struck not only by their beauty but by their absolute uniqueness (like snowflakes and fingerprints). That obsession has led him, as a scientist, to work to disprove the argument of intelligent design proponents against Darwinianism on the basis of the intricacy of the eye, which, they allege, could not have resulted from random natural selection but must indicate the presence of some creative force. Gray’s experiments prove inconclusive, however, until Karen (Brit Marling) arrives as his new lab assistant. She suggests a different approach to the problem: taking a sightless worm that possesses a gene in common with man and, through a series of experiments, ‘evolving’ it into a sighted creature.

By this time, however, Ian has found another interest. At a costume party he encounters a masked beauty with uncommonly attractive eyes. He not only photographs them but has steamy sex with their owner before she suddenly disappears. Naturally he’s desperate to find her again, and does—through a series of numerical coincidences that are apparently fated. She turns out to be Sofi (Astrid Berges-Frisbey), a model whose peepers are featured on a gigantic billboard that Ian, led by destiny’s clues, encounters along his subway route; and the advanced art of Googling allows him to identify and track her down.

Love quickly blossoms between the two, but so do Karen’s experiments, and suddenly Gray’s obsessions clash as the test worms see. After a whirlwind romance, Ian and Sofi are headed for marriage, but she’s uncomfortable with his rationalistic scientism. That might not be a deal-breaker, but in the event they’re separated by a terrible accident in a rickety elevator, and some years later we find Ian and Karen married with a child. Gray is now a celebrity whose work “The Complete Eye” is feted as having debunked the theory of intelligent design altogether, and apparently also given rise to an “eye registration” database. Things appear totally fine until another researcher asks the couple to bring their baby in for an examination that concentrates on—you guessed it—his eyes. The result sends Ian into an intellectual tailspin and on an investigation that takes him first to a dairy farm and then all the way to India.

In these latter stages “I Origins” raises big issues, most obviously the question of reincarnation. In the process it poses a challenge to the rationalistic absolutism represented by Ian and Karen—and the evolutionary beliefs they’ve always embraced. The problem is that it does so in a fashion that apparently wants to appear even-handed but in the end comes down on one side pretty definitively, but hardly convincingly. That’s fine, of course—a filmmaker has the right to take any position he wishes. What isn’t so tolerable is that Cahill makes his “case” through a cheap narrative trick that proves absolutely nothing except that some folks can share the same phobias. Equally unfortunate from the narrative point of view is a sudden cameo by William Mapother (from “Another Earth”) as a preacher, which is mildly unnerving but ultimately goes nowhere and comes across as extraneous. It’s perfectly okay if Cahill wants to have fun with some serious matters, so long as you’re not misled into taking what he has to say about them as anything other than hooey.

On the other hand, his film is executed adeptly, with Markus Forderer contributing cinematography that, when combined with Cahill’s deliberately elliptical editing and a moody score by Will Bates and Phil Mossman, creates a vaguely hallucinatory vibe suited to the weirdness of the plot. Pitt was perhaps not the best choice for Gray—putting glasses on him doesn’t make him any more persuasive as a brilliantly idiosyncratic scientist—but Marling’s brittle persona fits Karen perfectly, just as Berges-Frisbey’s sultry vivacity does the free-spirited Sofi. Steven Yeun adds some amusing moments as Ian’s lab colleague, and a young Indian girl named Kashish brings big, pleading eyes to an important role in the picture’s final stages.

Some viewers are probably going to proclaim “I Origins” as a smart sci-fi thriller. That sort of description confuses aspiration with accomplishment. There’s no doubt that it wants to be clever and deep. Unhappily, it’s actually rather goofy.