A documentary about building an ark turns into a funny, thoughtful rumination on the nature of human preservation.The phrase “arc of oblivion” sounds apocalyptic, as if it ought to be uttered in the unmistakable voice of Werner Herzog and accompanied by grave proclamations about the end of all things. “The Arc of Oblivion,” a documentary directed by Ian Cheney, in fact delivers both of those things. But they’re delivered in such a lighthearted, weird, thought-provoking manner that it’s less frightening than fun. And if you’re left thinking about disasters, it’s only natural: Cheney’s building a literal ark throughout. (Wordplay!)A mass-extinction flood is the ur-apocalypse in many ancient texts, but Cheney isn’t building an ark to rescue humanity, or to talk about Noah. Instead of what passes away, he’s thinking about what can be rescued from some nameless, shapeless future obliteration. “What from this world is worth saving?” he asks in voice-over near the beginning of the film, the first of many semi-rhetorical inquiries throughout. Having hired a carpenter to build an ark the size of a guesthouse in his parents’ rural Maine backyard, he feels like he owes us, and probably them, some answers. Is he building the ark because he’s examining this question, or vice versa? And does he expect any resolution?I don’t think he does. Instead, he invites us to start pondering questions — queries about why humans always want to save things, what kinds of things can be saved, and what we even really know about time, space and permanence. “The Arc of Oblivion” is a documentary, which means it captures something about life right now, archiving it for the future. But Cheney is also exploring the meaning of archiving itself, a query that takes him from the Sahara to the Alps, consulting a ceramics expert, a paleontologist, a speleologist (cave scientist), a dendrochronologist (scientist who studies tree rings) and many other specialists in fields I didn’t realize had their own names. Each provides a new way into thinking about why and how the human species tries to preserve its memories, alongside the futility of the task.Cheney got interested in the question because he’s a filmmaker in this digital age, which means he possesses piles of hard drives containing his footage that could be easily destroyed by a disaster, or even a brush with a very large magnet. Storing your memories in a relatively unstable form — which is to say, storing your memories at all (except, as one expert points out, on certain ceramics, which are basically permanent) — can in turn prompt a bit of instability in your sense of self. Who are you without your memories?I find this question of the permanence of things is arresting, particularly in an age where everything is easily disposable, and it’s more striking the older I get. That Cheney’s middle-aged quest started with his own digital footage is no mistake. Consider, for instance, the chilling headlines about studios permanently shelving their own movies, which means we’ll just never see them. In the past, a movie might be destroyed when a film canister caught fire. But there’s something disquieting about, essentially, a keystroke having the potential to wipe out labor that was years in the making, with hundreds of participants involved. We live in a world in which our movies, photos, music and more are essentially one wrong button push away from disappearing entirely. It’s hard not to feel like we could just as easily be deleted.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More