Computing and Philosophy pp 27-44 | Cite as
Are Gandy Machines Really Local?
Abstract
This paper discusses the empirical question concerning the physical realization (or implementation) of a computation. We give a precise definition of the realization of a Turing-computable algorithm into a physical situation. This definition is not based, as usual, on an interpretation function of physical states, but on an implementation function from machine states to physical states (as suggested by Piccinini G, Computation in physical systems. The Stanford encyclopedia of philosophy. http://plato.stanford.edu/archives/fall2012/entries/computation-physicalsystems. Accessed 5 Dec 2013, 2012). We show that our definition avoids difficulties posed by Putnam’s theorem (Putnam H, Representation and reality. MIT Press, Cambridge, 1988) and Kripke’s objections (Stabler EP Jr, Kripke on functionalism and automata. Synthese 70(1):1–22, 1987; Scheutz M, What is not to implement a computation: a critical analysis of Chalmers’ notion of implementation. http://hrilab.tufts.edu/publications/scheutzcogsci12chalmers.pdf. Accessed 5 Dec 2013, 2001). Using our notion of representation, we analyse Gandy machines, intended in a physical sense, as a case study and show an inaccuracy in Gandy’s analysis with respect to the locality notion. This shows the epistemological relevance of our realization concept. We also discuss Gandy machines in quantum context. In fact, it is well known that in quantum mechanics, locality is seriously questioned, therefore it is worthwhile to analyse briefly, whether quantum machines are Gandy machines.
Keywords
Machine State Physical Theory Turing Machine Transitive Closure Rigid DesignatorNotes
Acknowledgments
We thank Claudio Calosi, Maurizio Colucci, Paola Gentili, Marco Giunti, Rossella Lupacchini, Wilfried Sieg and Guglielmo Tamburrini for their comments and suggestions. We thank the reviewers who have commented our paper and the scholars attending the IACAP 2014 Conference for their questions.
References
- Beggs, E. J., & Tucker, J. V. (2007). Can Newtonian systems, bounded in space, time, mass and energy, compute all functions? Theoretical Computer Science, 371(1), 4–19.CrossRefGoogle Scholar
- Calosi, C., & Graziani, P. (2014). Mereology and the sciences. Parts and wholes in the contemporary scientific context (Synthese library, Vol. 371). Heidelberg/New York/Dordrecht/London: Springer.Google Scholar
- Carnap, R. (1945). The two concepts of probability. Philosophy and Phenomenological Research, 5(4), 513–532.CrossRefGoogle Scholar
- Carnap, R. (1950). Logical foundations of probability. Chicago: Chicago University of Chicago Press.Google Scholar
- Chalmers, D. J. (1996). Does a rock implement every finite-state automaton? Synthese, 108, 309–333.CrossRefGoogle Scholar
- Chalmers, D. J. (2011). A computational foundation for the study of cognition. Journal of Cognitive Science, 12, 325–359.CrossRefGoogle Scholar
- Copeland, B. J. (2015). The Church-Turing thesis. In E. N. Zalta (Ed.), The Stanford encyclopedia of philosophy. Stanford: Metaphysics Research Lab. http://plato.stanford.edu/archives/sum2015/entries/church-turing. Accessed 24 Sep 2015.
- Copeland, B. J., & Shagrir, O. (2007). Physical computation: How general are Gandy’s principles for mechanism. Mind and Machines, 17(2), 217–231.CrossRefGoogle Scholar
- Cotogno, P. (2003). Hypercomputation and the physical Church-Turing Thesis. British Journal for the Philosophy of Science, 54(2), 181–223.CrossRefGoogle Scholar
- Cushing, J. T., & McMullin, E. (1989). Philosophical consequences of quantum theory. Notre Dame: University of Notre Dame Press.Google Scholar
- Deutsch, D. (1985). Quantum theory, the Church-Turing principle and the universal quantum computer. Proceedings of the Royal Society A, 400, 97–117.CrossRefGoogle Scholar
- Gandy, R. (1980). Church’s thesis and principles for mechanisms. In J. Barwise, H. J. Keisler, & K. Kunen (Eds.), The Kleene symposium (pp. 123–148). Dordrecht: North Holland.CrossRefGoogle Scholar
- Gandy, R. (1993). On the impossibility of using analogue machines to calculate non-computable functions. Unpublished.Google Scholar
- Giunti, M. (1997). Computation, dynamics and cognition. Oxford: Oxford University Press.Google Scholar
- Herken, R. (1995). The Universal Turing machine: A half-century survey. Wien/New York: Springer.CrossRefGoogle Scholar
- Horsman, C., Stepney, S., Wagner, R., & Kendon, V. (2014). When does a physical system compute? Proceeding of the Royal Society A, 470(2169), 20140182.Google Scholar
- Jarrett, J. P. (1984). On the physical significance of the locality conditions in Bell argument. Noûs, 18, 569–589.CrossRefGoogle Scholar
- Kieu, T. D. (2002). Quantum hypercomputation. Minds and Machines, 12(4), 461–502.CrossRefGoogle Scholar
- Kleene, S. C. (1952). Introduction to metamathematics. Princeton: Van Nostrand.Google Scholar
- Kripke, S. A. (2013). The Church-Turing ‘Thesis’ as a special corollary of Gödel’s completeness theorem. In B. J. Copeland, C. J. Posy, & O. Shagrir (Eds.), Computability: Turing, Gödel, Church, and Beyond (pp. 77–104). Cambridge: MIT Press.Google Scholar
- Maudlin, T. (1994). Quantum non-locality and relativity. Oxford: Blackwell.Google Scholar
- Mendelson, E. (1990). Second thoughts about Church’s thesis and mathematical proof’s. The Journal of Philosophy, 87(5), 225–233.CrossRefGoogle Scholar
- Olszewski, A., Wolenski, J., & Janusz, R. (2007). Church’s thesis after 70 years. Frankfurt: Ontos Verlag.Google Scholar
- Piccinini, G. (2012). Computation in physical systems. The Stanford encyclopedia of philosophy. http://plato.stanford.edu/archives/fall2012/entries/computation-physicalsystems. Accessed 5 Dec 2013.
- Putnam, H. (1988). Representation and reality. Cambridge: MIT Press.Google Scholar
- Rovelli, C. (2004). Quantum gravity. Cambridge: Cambridge University Press.CrossRefGoogle Scholar
- Scheutz, M. (1999). When physical systems realize functions…. Minds and Machines, 9(2), 161–196.CrossRefGoogle Scholar
- Scheutz, M. (2001). What is not to implement a computation: A critical analysis of Chalmers’ notion of implementation. http://hrilab.tufts.edu/publications/scheutzcogsci12chalmers.pdf. Accessed 5 Dec 2013.
- Shagrir, O. (1997). Two dogmas of computationalism. Minds and Machines, 7(3), 321–344.CrossRefGoogle Scholar
- Shagrir, O. (2002). Effective computation by humans and machines. Minds and Machines, 12(2), 221–240.CrossRefGoogle Scholar
- Shagrir, O., & Pitowsky, I. (2003). Physical hypercomputation and the Church-Turing Thesis. Minds and Machines, 13(1), 87–101.CrossRefGoogle Scholar
- Sieg, W. (2002). Calculations by man & machine: Mathematical presentation. In Synthese series, proceedings of the Cracow international congress of logic, methodology and philosophy of science (pp. 245–260). Dordrecht: Kluwer Academic Publishers.Google Scholar
- Sieg, W. (2008). Church without dogma: Axioms for computability. In S. B. Cooper, B. Löwe, & A. Sorbi (Eds.), New computational paradigms: Changing conceptions of what is computable (pp. 139–152). Berlin: Springer.CrossRefGoogle Scholar
- Sieg, W., & Byrnes, J. (1999). An abstract model for parallel computations. Gandy’s thesis. The Monist, 82(1), 150–164.CrossRefGoogle Scholar
- Simons, P. (1987). Parts. Oxford: Clarendon.Google Scholar
- Soare, R. I. (1996). Computability and recursion. The Bulletin of Symbolic Logic, 2(3), 284–321.CrossRefGoogle Scholar
- Stabler, E. P., Jr. (1987). Kripke on functionalism and automata. Synthese, 70(1), 1–22.CrossRefGoogle Scholar
- Syropoulus, A. (2008). Hypercomputation: Computing beyond Church-Turing barrier. New York: Springer.CrossRefGoogle Scholar
- Tamburrini, G. (2002). I matematici e le macchine intelligenti. Milano: Bruno Mondadori.Google Scholar
- Turing, A. M. (1936). On computable numbers with an application to the Entscheidungsproblem. Proceedings of the London Mathematical Society, 42(2), 230–265. A correction in 43(2) (1937), (pp. 544–546). Oxford: Oxford University Press.Google Scholar