Retired professor of physics and philosophy at Boston University, on June 19, 2017, at home. Beloved husband of Karin D. (Hansen) von Trotha-Cohen and the late Robin (Hirshhorn) Cohen. Devoted father of Deborah Strod (Eran), Daniel Cohen (Nancy), and Michael Cohen (Dianna Goodwin). Loving grandfather of Sarah, Mike, Joseph, Laurel, Rudi, Jacob, Max, Maya, and Jesse; great-grandfather of Hugo , Amelia, Kaylee, and Kayleigh; and great-great-grandfather of Naia and Nova. Dear Brother of Myrna Fisher and the late Judi Driscoll. Dear Brother-in-law of Gene LePere, Naomi Caryl, and the late Gordon Hirshhorn. Services at Temple Isaiah, 55 Lincoln St., Lexington, MA, Thursday, June 22, 2017 at 10:00 am. Following burial at Mt. Auburn Cemetery, shiva and gathering will be held at his residence from 3:30-8:30 pm. A memorial celebration will be planned. Donations in his memory may be made to the American Civil Liberties Union (aclu.org), the Union of Concerned Scientists (ucsusa.org), or the International Rescue Committee (rescue.org).