Digital physics is a speculative idea that the universe can be conceived of as a vast, digital computation device, or as the output of a deterministic or probabilistic computer program. The hypothesis that the universe is a digital computer was proposed by Konrad Zuse in his book Rechnender Raum (translated into English as Calculating Space). The term digital physics was employed by Edward Fredkin in 1978, who later came to prefer the term digital philosophy. Fredkin encouraged the creation of a digital physics group at what was then MIT's Laboratory for Computer Science, with Tommaso Toffoli and Norman Margolus as primary figures.
Digital physics suggests that there exists, at least in principle, a program for a universal computer that computes the evolution of the universe. The computer could be, for example, a huge cellular automaton.
Extant models of digital physics are incompatible with the existence of several continuous characters of physical symmetries, e.g., rotational symmetry, translational symmetry, Lorentz symmetry, and the Lie group gauge invariance of Yang–Mills theories, all central to current physical theory. Moreover, extant models of digital physics violate various postulates of quantum physics, belonging to the class of theories with local hidden variables that have so far been ruled out experimentally using Bell's theorem.
- Schmidhuber, J., "Computer Universes and an Algorithmic Theory of Everything"; A Computer Scientist's View of Life, the Universe, and Everything.
- 6.895 Digital Physics, MIT Course Catalog Listing, 1978, http://simson.net/ref/1978/6.895%20Digital%20Physics/1978-01-17%20Digital%20Physics%20Lecture%20Outline.pdf
- See Fredkin's Digital Philosophy web site.
- Zuse, Konrad, 1967, Elektronische Datenverarbeitung vol 8., pages 336–344
- Fritz, Tobias (June 2013). "Velocity polytopes of periodic graphs and a no-go theorem for digital physics". Discrete Mathematics. 313 (12): 1289–1301. doi:10.1016/j.disc.2013.02.010.
- Aaronson, Scott (September 2002). "Book Review on A New Kind of Science by Stephen Wolfram". Quantum Information and Computation (QIC). arXiv:quant-ph/0206089.
- Jaeger, Gregg (2018). "Clockwork Rebooted: Is the Universe a Computer?". Quantum Foundations, Probability and Information: 71–91. doi:10.1007/978-3-319-74971-6_8.
- Robert Wright, "Did the Universe Just Happen?", Atlantic Monthly, April 1988 - Article discussing Fredkin and his digital physics ideas