Appendix C. Many-Worlds Theories.Sarfatti Note. Stapp here shows that the many-worlds view has what Wheeler called "excess metaphysical baggage". Occam's razor requires that we reject it for either a Heisenbergian view or a Bohmian view. What does this do to David Albert's argument of photographiing other worlds?I have accepted here Heisenberg's idea that there are real events, that each one represents a transition from "the possible" to "the actual", and that the quantum state can be regarded as a representation of the "objective tendencies" for such events to occur. In fact, it is difficult to ascribe any coherent meaning to the quantum state in the absence of such events. For there is then nothing in the theory for the probabilities represented by the wave function to be probabilities of: What does it mean to say that something happens with probability P if everything happens?
In our model, if we say that there is no collapse then all the branches continue to exist: there is no singling out and actualization of one single branch. Each of the several branches will evolve independently of the others, and hence it is certainly plausible to say that the different realms of experience that we would like to associate with the different branches should be independent and non communicating: the records formed in one branch will control only that one branch, and have no effect upon the others. But if there is no collapse then it would seem that each of the corresponding separate branches should occur with probability unity. Yet that would not yield a match with experience. In order to get a match with experience we must be able to effectively discard in the limit of an infinite number of repetitions of an experiment those branches that have a quantum weight that tends to zero in this limit. That is, quantum states with tiny quantum weights should occur almost never: they should not occur with probability unity! So without some added ontological or theoretical structure the many-worlds (i.e., no-collapse) theories fail to give a sensible account of the statistical predictions of quantum theory.
Of course, the key question is not whether a certain experience X occurs, but rather whether my experience will be experience X. However, the idea that many experiences occur, but that my experience will be only one of them involves some new sort of structure involving "choice" and "my". It involves a structure that goes beyond the idea of a quantum state of the world evolving in accordance with the Schroedinger equation. At that basic quantum level the various classically describable branches are components that are combined conjunctively: the universe consists of branch 1 and branch 2 and branch 3 and not branch 1 or branch 2 or branch 3 or ... Yet the world must be decomposed in terms of alternative possibilities in order to assign different statistical weights to the different components: the 'and' composition given by the basic quantum structure must be converted into an 'or' composition. This restructuring seems to require the introduction of some new sort of beingness: the idea of a psychological being that splits into alternative branches while the associated physical body, evolving in accord with the Schrodinger equation, is splitting into a conjunction of corrresponding branches. By an appropriate assignment of statistical weights to the various alternative psychological branches one could then explain the statistical predictions of quantum theory, but this would seem to be an ontological tour de force compared to the simpler Wigner idea, adopted here, that thoughts correspond to real Heisenberg-type events.
(1) Stapp, Amer J Phys 40, 1098-1116 (1977)
(2) J von Neumann, The Mathematical Foundations of Quantum Mechanics, Princeton, 1955 Ch VI Sec 1
(3) N. Weiner, Tech. Rev. 34 (9132) 201-202, 222, 224; Philos. Sci. 1 (1934), 78-98
(4) J.B.S. Haldane, Philos. Sci. 3 (1936), 307-319
(5) Stapp, Mind, Matter, and Quantum Mechanics, Springer Verlag (1993)
(6) S.M. Kosslyn, Image and the Brain, MIT (1994)
(7) E. Wigner, The Scientist Speculates, ed. I. J. Good, Basic Books (1962)
(8)A. Aspect, P. Grangier, G. Roger, Phys Rev Lett. 49 (1982), 1804-1807
(9) P.S. Churchland, Neurophilosophy ... MIT Press (1992)
(10) Churchland, ibid, p.295
(11) Stapp, Symposium on the Foundations of Modern Physics 1990 World Scientific, 1991