Mountain climbers, the real-deal ones, the ones who fearlessly risk life and limb to conquer peaks, arouse a natural human curiosity about how they can be so undaunted. Besides being mortal and being 60 percent water, these people’s programming seems to have absolutely no relation to how us normal folks function. You don’t know if they’re enlightened beings who have found something ethereal above the pettiness of people down below, or if they’re neanderthals who have no civilizational restraints. Meru, a documentary now showing at Cornell Cinema on Thursday and Saturday, chronicles a group of these climbers. Specifically, Meru focuses on Conrad Anker, Jimmy Chin and Renan Ozturk as they try to hike the “Shark’s Fin” route of Meru, a peak in the Indian Himalayas.