Mike Cahill certainly is in no rush. 2011’s first feature Another Earth had a tantalising idea - what would it really mean to Earth’s population if we encountered a mirror planet? But he took his sweet time in getting about it. This follow up lays a lot of pipe too and feels like there’s almost an hour gone before the plot finally wakes up. But, looking back, the writer-director was chipping away all the time, laying clues and hints as to where he was headed and while where he ends up will cause debate it was certainly fun getting there.

Michael Pitt is a molecular biologist who ropes in a first year student (Marling, star of Cahill’s Another Earth) on his current research: fascinated by the human eye, ‘proof’ they say of an intelligent designer rather than evolution, Pitt and Marling set out to prove that if they can genetically engineer a worm with an eye, then that disproves God. Or something. Outside the lab, Pitt’s becomes involved with a kooky Argentinean model with beautiful eyes, Astrid Bergés-Frisbey, who believes in reincarnation, and who has far reaching consequences and takes his research into a realm he didn’t think possible.

If a sightless organism can grow an eye, can a scientist develop a sense of spirituality? This is the interesting premise at the heart of I Origins and when it comes to the eternal question - is there a God? - Cahill’s film refuses to scoff at either argument, too busy quietly confusing everyone with its patient story.

With its bleached out colours, actors in close confines, its reserved tone, and its general "What the f**l is going on?" (as fellow scientist Steven Yeun exclaims at one point) plotting, Cahill’s film behaves like a more accessible Shane Carruth (Primer, Upstream Color). While it might be a real conundrum, there’s no Carruth-esque mental gymnastics here.

The inclusion of a romance helps to let some air into the story, but with that comes a very un-Cahill moment; when Pitt happens across Bergés-Frisbey on the subway, he slips up behind her, places his headphones on her head, and plays her a song. Of course she falls in love. It’s more Cameron Crowe than Mike Cahill and is at odds with the rest of the film.

Mike Cahill is setting himself up to be a real talent - let’s hope he doesn’t mimic his stories and take ages doing that.