The idea that the universe is a digital computation device

Digital physics

This scientific article needs additional citations to secondary or tertiary sources such as review articles, monographs, or textbooks.  Please add such references to provide context and establish the relevance of any primary research articles cited. Unsourced or poorly sourced material may be challenged and removed.  (May 2022) (Learn how and when to remove this template message)

This article possibly contains original research. The state of this niche topic is unclear. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed.  (May 2022) (Learn how and when to remove this template message)

Digital physics

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 <a href="/en/Deterministic" title="Deterministic" class="mw-redirect wl">deterministic</a> or <a href="/en/Probabilistic" title="Probabilistic" class="mw-redirect wl">probabilistic</a> <a href="/en/Computer_program" title="Computer program" class="wl">computer program</a>.<a href="#cite_note-:0-1" style="counter-reset: mw-Ref 1;">[1]</a> The hypothesis that the <a href="/en/Universe" title="Universe" class="wl">universe</a> is a <a href="/en/Digital_computer" title="Digital computer" class="mw-redirect wl">digital computer</a> was proposed by <a href="/en/Konrad_Zuse" title="Konrad Zuse" class="wl">Konrad Zuse</a> in his 1969 book <a href="/en/Rechnender_Raum" title="Rechnender Raum" class="mw-redirect wl">Rechnender Raum</a><a href="#cite_note-2" style="counter-reset: mw-Ref 2;">[2]</a> ("Calculating Space").<a href="#cite_note-3" style="counter-reset: mw-Ref 3;">[3]</a> The term digital physics was coined by <a href="/en/Edward_Fredkin" title="Edward Fredkin" class="wl">Edward Fredkin</a> in 1978,<a href="#cite_note-4" style="counter-reset: mw-Ref 4;">[4]</a> who later came to prefer the term digital philosophy.<a href="#cite_note-5" style="counter-reset: mw-Ref 5;">[5]</a> Fredkin encouraged the creation of a digital physics group at what was then <a href="/en/Massachusetts_Institute_of_Technology" title="Massachusetts Institute of Technology" class="wl">MIT</a>'s <a href="/en/Laboratory_for_Computer_Science" title="Laboratory for Computer Science" class="mw-redirect wl">Laboratory for Computer Science</a>, with <a href="/en/Tommaso_Toffoli" title="Tommaso Toffoli" class="wl">Tommaso Toffoli</a> and <a href="/en/Norman_Margolus" title="Norman Margolus" class="wl">Norman Margolus</a> as primary figures.

<div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none" about="#mwt1">The idea that the universe is a digital computation device</div>
<style data-mw-deduplicate="TemplateStyles:r1033289096" typeof="mw:Extension/templatestyles mw:Transclusion">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}</style>
<style data-mw-deduplicate="TemplateStyles:r1097763485" typeof="mw:Extension/templatestyles mw:Transclusion">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}html.client-js body.skin-minerva .mw-parser-output .mbox-text-span{margin-left:23px!important}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}</style><style data-mw-deduplicate="TemplateStyles:r1086701767" typeof="mw:Extension/templatestyles">.mw-parser-output .multiple-issues-text{width:95%;margin:0.2em 0}.mw-parser-output .multiple-issues-text>.mw-collapsible-content{margin-top:0.3em}.mw-parser-output .compact-ambox .ambox{border:none;border-collapse:collapse;background-color:transparent;margin:0 0 0 1.6em!important;padding:0!important;width:auto;display:block}body.mediawiki .mw-parser-output .compact-ambox .ambox.mbox-small-left{font-size:100%;width:auto;margin:0}.mw-parser-output .compact-ambox .ambox .mbox-text{padding:0!important;margin:0!important}.mw-parser-output .compact-ambox .ambox .mbox-text-span{display:list-item;line-height:1.5em;list-style-type:disc}.mw-parser-output .compact-ambox .ambox .mbox-image,.mw-parser-output .compact-ambox .ambox .mbox-imageright,.mw-parser-output .compact-ambox .ambox .mbox-empty-cell,.mw-parser-output .compact-ambox .hide-when-compact{display:none}</style>
Digital physics suggests that there exists, at least in principle, a <a href="/en/Computer_program" title="Computer program" class="wl">program</a> for a <a href="/en/Universal_computer" title="Universal computer" class="mw-redirect wl">universal computer</a> that computes the evolution of the <a href="/en/Universe" title="Universe" class="wl">universe</a>. The computer could be, for example, a huge <a href="/en/Cellular_automaton" title="Cellular automaton" class="wl">cellular automaton</a>.<a href="#cite_note-:0-1" style="counter-reset: mw-Ref 1;">[1]</a><a href="#cite_note-6" style="counter-reset: mw-Ref 6;">[6]</a> 

Extant models of digital physics are incompatible with the existence of several continuous characters of physical <a href="/en/Symmetry_in_physics" title="Symmetry in physics" class="mw-redirect wl">symmetries</a>,<a href="#cite_note-7" style="counter-reset: mw-Ref 7;">[7]</a> e.g., <a href="/en/Rotational_symmetry" title="Rotational symmetry" class="wl">rotational symmetry</a>, <a href="/en/Translational_symmetry" title="Translational symmetry" class="wl">translational symmetry</a>, <a href="/en/Lorentz_symmetry" title="Lorentz symmetry" class="mw-redirect wl">Lorentz symmetry</a>, and the <a href="/en/Lie_group" title="Lie group" class="wl">Lie group</a> gauge invariance of <a href="/en/Yang–Mills_theory" title="Yang–Mills theory" class="wl">Yang–Mills theories</a>, all central to current physical theory. Moreover, extant models of digital physics violate various well-established features of <a href="/en/Quantum_physics" title="Quantum physics" class="mw-redirect wl">quantum physics</a>, belonging to the class of theories with local <a href="/en/Hidden_variable_theory" title="Hidden variable theory" class="mw-redirect wl">hidden variables</a> that have so far been ruled out experimentally using <a href="/en/Bell's_theorem" title="Bell's theorem" class="wl">Bell's theorem</a>.<a href="#cite_note-8" style="counter-reset: mw-Ref 8;">[8]</a><a href="#cite_note-9" style="counter-reset: mw-Ref 9;">[9]</a>

However, covariant discrete theories can be formulated that preserve the aforementioned symmetries.<a href="#cite_note-10" style="counter-reset: mw-Ref 10;">[10]</a>

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. 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, 