We may not always be able to find or recognize the truth, he would admit, but it exists, and can be discovered much oftener than it is. Morris is an Enlightenment thinker, an empiricist, and an anti-postmodernist. He means that most of us, most of the time, are delighted to believe stories about ourselves or other people or the world that are powerful or convenient but do not happen to be true. The great subject of Morris’ filmmaking career is people’s “unrestrained enthusiasm for bullshit,” as he said near the end of our conversation. But we haven’t actually learned anything from his example. If there’s a lesson in Morris’ new interview film “The Unknown Known,” which is both a twist on Rumsfeld’s most famous phrase and a description of its subject, it might be this: We’ve convinced ourselves we won’t make the same mistake and believe a self-convinced con artist like Rumsfeld again. “It’s all just smugness, self-justification and self-satisfaction.” We were sitting in a crowded, noisy New York restaurant trying to make sense of the philosophical universe of Donald Rumsfeld, which could put anyone in a dark mood. “I think Mark Twain was wrong: History does not rhyme,” Errol Morris said, after I had switched off my recorder and we were having coffee.

The unknown known