What are we to feel? How can we even know what to feel on the 14th anniversary? Abiding grief, certainly. Two thousand, seven hundred and fifty three people were killed at the World Trade Center on Sept. 11, 2001. But there is joy, too. New York City did not merely bounce back. It roared back, seemingly more vital than ever. Yet the joy is tempered by regret. An ever-growing security apparatus — designed, we are told, to prevent another 9/11 —touches almost every aspect of our monitored, restricted lives. And the regret is softened by the pleasure of seeing a new World Trade Center, flaws and all, working its way back as a lively, crowded downtown crossroads. How can so much ambivalence be captured in a single memorial? The Tribute in Light shows how, as it has since March 11, 2002, when the twin beams first pierced the sky over Lower Manhattan, six months after the attack, and only three months after the fires at the trade center were officially declared extinguished. It succeeds because it offers no narrative, no interpretation, no mediation. At a distance, it’s not even clear whether the shafts are soaring upward or beaming down from the heavens. You can read them as a divine symbol or as abstract architecture or simply as an annual public art project. The pinstripes created by the 88-lamps arrays may remind you of the striations in the twin towers’ facades, or the rivulets in the memorial waterfalls, which may in turn suggest the passage of souls through space. Or not. The point is: no one is telling you what to think. You are merely invited to do so. For free. Most people don’t even know who created the Tribute in Light. Independently and almost simultaneously, five artists and architects — John Bennett, Gustavo Bonevardi, Richard Nash Gould, Julian LaVerdiere and Paul Myoda — came up with roughly the same idea in the autumn of 2001. The Municipal Art Society helped harness and meld their visions and make the project a reality, working with the lighting designer Paul Marantz and with Michael Ahern, an events producer. Since 2012, the display has been orchestrated by the National September 11 Memorial and Museum. What hasn’t changed is that the lights are to go on at dusk and remain illuminated until darkness gives way to dawn.