Are Black Holes Really Paradoxical? An Interview with David Wallace

If black holes destroy information, they create a serious conflict within otherwise well-established theories.

Today in Quanta magazine, I have an article on recent efforts to de-paradoxize black holes. Before you dive into the details, you might wonder about the framing. How paradoxical are black holes, really? Physicists and science writers throw around the word “paradox,” but do these cosmic sinkholes pose any out-and-out contradiction? I put the question to David Wallace at the Foundations of Physics conference in Utrecht in July 2018.

Wallace, a theoretical physicist turned philosopher, now at the University of Pittsburgh, is best known for championing the many-worlds interpretation of quantum mechanics. But he also ponders black holes and much else. In 2017 he argued that black holes really are paradoxical. He was responding to fellow philosopher Tim Maudlin of New York University, who had wrote a scornful takedown of the paradox, and Craig Callender of U.C. San Diego, who has been similarly dubious.

In his riposte, Wallace cited a version of the information-loss paradox put forward in 1993 by physicist Don Page of the University of Alberta. Whereas Stephen Hawking’s original version of that paradox focused on what happens when black holes die, Page noted that they also go through a midlife crisis. The early onset of their strange behavior, Wallace argues, creates an internal conflict within the analysis and justifies the designation of “paradox.”

More’s at stake than philosophical taxonomy. As I discuss in the Quanta article and in my book, the paradox suggests physics is fundamentally nonlocal and the concept of spacetime breaks down.