There are many head-shaking moments in Behind the Curve—a 2018 documentary, now on Netflix, that follows luminaries of the Flat Earth movement, particularly YouTuber Mark Sargent.  The most surprising may be the rigor with which believers in a Flat Earth disprove themselves. Twice in Behind the Curve, experiments show the opposite of what Flat Earth advocates hope to demonstrate, with one such experiment, involving a flashlight, serving as the documentary’s ending. “Science is having a problem combatting what we are doing,” Mark Sargent says early in Behind the Curve, citing the fact that he can see Seattle skyscrapers from his mother’s home on Whidbey Island, when he presumes they should be hidden behind the Earth’s curvature. “Neil Degrasse Tyson—I hate saying his name, we call him He-Who-Shall-Not-Be-Named—says that, ‘It’s a growing anti-intellectual movement that borders on the end of civilization and democracy as we know it.’” Cut to Tyson’s 2016 appearance on Comedy Central’s The Nightly Show with Larry Wilmore : “The Earth isn’t fucking flat.” “The reason why we’re winning against science is that science just throws math at us,” Sargent says in Behind the Curve. Sargent a...