We live in an era in which the overwhelming majority of filmgoers will have no experience of military life whatsoever, either as veterans or relatives thereof. “Dunkirk,” a visually stunning film—overwhelming in IMAX— will not give those audience members the illusion that by having watched the film they understand what war is. They will be moved, I’m sure; this particular story cannot be anything but. But its very distance from the communal character of military experience marks it as a film of our time trying to reach back to another era, when military culture was more generally understood, and show us: see, this is what you no longer understand.