John Wheeler

John Archibald Wheeler was an American theoretical physicist who taught at Princeton and later at the University of Texas at Austin. He worked with Niels Bohr on nuclear fission, helped revive general relativity research and popularised the term 'black hole'. Late in his career he proposed 'it from bit': the idea that every physical thing derives its existence from the answers to yes-or-no questions posed in observation, making information basic to physics. He also supervised Hugh Everett's doctoral work.

Key ideas

• It from bit: physical reality arises, at bottom, from information, the answers to binary questions registered in observation.
• The universe is participatory, in that observation plays a role in bringing about what is real.
• Delayed-choice experiments suggest that how we measure now settles how a quantum system is to be described in the past.
• Geometry and gravity are central to physics, and spacetime itself should be treated as a dynamic participant.

Major works

• "The Mechanism of Nuclear Fission" (1939, with Niels Bohr)
• Gravitation (1973, with Charles W. Misner and Kip S. Thorne)
• "Information, Physics, Quantum: The Search for Links" (1990, in W. H. Zurek, ed., Complexity, Entropy and the Physics of Information)
• Geons, Black Holes, and Quantum Foam (1998, with Kenneth Ford)

In the conversation

• Question Is Wheeler’s “it from bit” a physics proposal or a piece of metaphysics? Lars Eriksen · 5 replies