In Memoriam: Bernard d’Espagnat

Photo credit: Templeton Prize/Laurence Godart
Photo credit: Templeton Prize/Laurence Godart

Bernard d’Espagnat, physicist, philosopher of science, and 2009 Templeton Prize Laureate, passed away on Saturday, August 1, at the age of 93.

D’Espagnat, who was professor emeritus of theoretical physics at the University of Paris-Sud, played a key role during a revolutionary period of exploration and development in quantum mechanics in the 1960s and 1970s, specifically on experiments testing the “Bell’s inequalities” theorem. Results published in 1981 and 1982 verified that Bell’s inequalities were violated in the way quantum mechanics predicts, leading to a confirmation of the phenomenon of “non-local entanglement.” In 2009, New Scientist explained this meant that “if there is some reality beneath quantum mechanics, it must be nonlocal—that is, things can influence one another instantaneously regardless of how much space stretches between them, violating Einstein’s insistence that nothing can travel faster than the speed of light.”

D’Espagnat’s writings explored the philosophical importance of these physics-based insights into the nature of reality. He argued that quantum physics indicates that ultimate reality cannot be described, pointing to a reality beyond the reach of empirical science. He called this “veiled reality,” a hidden yet unifying domain beneath what we perceive as time, space, matter, and energy—concepts challenged by quantum physics as possible mere appearances.

At the 2009 Prize news conference, held at UNESCO in Paris, the late Dr. Jack Templeton noted that “instead of simply measuring the limits of quantum physics, d’Espagnat has explored the unlimited, the openings that new scientific discoveries offer in pure knowledge and in questions that go to the very heart of our existence and humanity.”

D’Espagnat emphasized that since science cannot tell us anything certain about the nature of being, clearly it cannot tell us with certainty what it is not. “Mystery is not something negative that has to be eliminated,” he said at the news conference. “On the contrary, it is one of the constitutive elements of being.”

Brian Greene, professor of mathematics and physics at Columbia University, wrote at the time: “Bernard d’Espagnat is among a small coterie of courageous thinkers who over the course of many decades has worked tirelessly to meld scientific and philosophical insights to reveal the full wonder of quantum reality.”