Foundations of Physics

, Volume 16, Issue 6, pp 533–550 | Cite as

Computability and physical theories

  • Robert Geroch
  • James B. Hartle
Part VI. Invited Papers Dedicated To John Archibald Wheeler


The familiar theories of physics have the feature that the application of the theory to make predictions in specific circumstances can be done by means of an algorithm. We propose a more precise formulation of this feature—one based on the issue of whether or not the physically measurable numbers predicted by the theory are computable in the mathematical sense. Applying this formulation to one approach to a quantum theory of gravity, there are found indications that there may exist no such algorithms in this case. Finally, we discuss the issue of whether the existence of an algorithm to implement a theory should be adopted as a criterion for acceptable physical theories.

“Can it then be that there is... something of use for unraveling the universe to be learned from the philosophy of computer design?”

—J. A. Wheeler(1)


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Copyright information

© Plenum Publishing Corporation 1986

Authors and Affiliations

  • Robert Geroch
    • 1
  • James B. Hartle
    • 2
  1. 1.Enrico Fermi InstituteChicago
  2. 2.Department of PhysicsUniversity of CaliforniaSanta Barbara

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