Hotshot grad student Ian Gray (Pitt) is researching the evolution of human eyes when he meets Sofi (Berges-Frisbey), a mysterious girl with centralised heterochromia and a hatful of kooky beliefs concerning the spirit world and reincarnation. Working with Karen (Marling), his brilliant young assistant, Ian ultimately hopes to prove that eyes have evolved, thereby ruling out any supernatural notions about creationism or intelligent design. A strange sequence of event gives the scientist pause for thought. Might there be more to heaven and Earth than dreamt of in his philosophy?

Right-minded humans don't use patronising phrases such as "thinking man's crumpet" any more. And yet when the New York Times profiled marvellous movie multi-tasker Brit Marling last January, the headline read: "How to succeed in hollywood despite being really beautiful."

In Sound of My Voice and Another Earth – films she co-authored, produced and starred in – Marling has created her own genre, a cerebral lo-fi subset of science fiction that dares to ask big questions about life, the universe, and everything in an age defined by shrugging and sarcasm. I Origin was written by Another Earth director Mark Cahill. The film clearly belongs with these early Marling pictures, but it lacks the nuance of its predecessors and, far too soon, gives in to the irrational side of the argument.

The midsection meanders and there are too many slow-motion sequences. But these minor quibbles are offset by interesting ideas about irreducible complexity and iris recognition. A not-quite Marling picture is still a million times smarter than anything else out there