Quantum computers and reality: Deutsch's anti-positivist campaign for explanations-in-general, apart from his Many Worlds Interpretation.
Abstract
David Deutsch (Oxford University) is known for ``Deutsch's algorithmm"---for going beyond the initial ideas about quantum computing (QC) of Benioff, Bennett and Feynman, to describe a quantum Turing machine, and sparking today's widespread experimental research to actually build one. Deutsch does not accept the standard Copenhagen Interpretation (CI) of quantum mechanics (QM); he supports the Many Worlds Interpretation (MWI) and credits it for his insights. In his book, The Fabric of Reality, and numerous articles and talks, he argues that the the adoption of the MWI is phnecessary for making the advances required for quantum computing. His argues that physicists must resolutely take a ``realistic" viewpoint to its logical conclusions, and, that the MWI is phthe realistic theory. In response to ubiquitous assertions by the majority of physicists that ``both systems give the same numbers," and ``all physics does (or can do) is to predict the outcome of experiments," he argues strenuously for the importance of explanations in quantum physics, and to scientific progress in general. Hence, I argue that there are two, reasonably separable, layers here: (i) opposition to positivist and instrumentalist arguments against the validity and/or value of phany explanation(s) phas such, and (ii) an argument about just what is the correct explanation: the MWI over the CI. While establishing the validity of (i) may possibly undermine CI's spirit, nevertheless (i) can be strongly validated independent from complicatons of an overlap with issues of the interpretation of QM. I develop some simple, historical contradictions regarding point (i), (without passing judgement on Deutsch's MWI or involving the CI). For example, the majority viewpoint identifies its seemingly ``non- philosophical" and non-``methaphysical" mindset as archtypically ``scientific", while seemingly quite unaware of the theoretical difficuties with positivist notions of truth, such as the fact that the foundations of universal phclassical computation theory rest squarely upon the work of Gödel. His proof (undecideability) showed logical-positivist notions of truth to be clearly mistaken.(1) It is therefore not surprising that Deutsch, today working to achieve a more powerful and general phquantum version of the Church-Turing thesis and phQuantum Universal Computation, rejects positivist notions of truth, just as Gödel found it necessary to do in the process of clearing the road to the development of the phclassical versions. Up to this point, Deutsch stands on solid, established ground, and this is, it seems, independent of anyone's interpretation of QM. In summary, Deutsch is correctly seeking to discredit the logical positivist and instrumentalist surfeit of the majority of the physics community, and it appears that this can be done without acceptance of the MWI. Assesement of this second part of his program (MWI) is beyond the scope of the present paper. (1) Davis, Martin, "The Universal Computer" Norton, NY, 2000, pp. 118-9.
- Publication:
-
APS April Meeting Abstracts
- Pub Date:
- April 2002
- Bibcode:
- 2002APS..APRO15003O