Advances in Quantum Theory

I discuss the meaning of probability in the Everett-Wheeler inter-pretation of quantum mechanics, together with the problem of defining histories. To resolve these, I propose an understanding of probability arising from a form of temporal logic: the probability of a future-tense proposition is identified with its truth value in a many-valued and context-dependent logic. In short, probability is degree of truth. These ideas appear to be new (though I expect correction on this), but they are natural and intuitive, and relate to traditional naive ideas of time and chance. Indeed, I argue that Everettian quantum mechan-ics is the only form of scientific theory that truly incorporates the perception that the future is open. 1 FOREWORD This talk was delivered under the title “The Everett interpretation and the open future”. After the talk, a member of the audience expressed sur-prise that I had never mentioned many worlds or splitting observers. I ex-plained that I regarded the “many worlds interpretation ” as a betrayal of Everett’s original idea: it introduces problems of defining worlds and mo-ments of splitting which are equivalent to the measurement problem which Everett intended to solve (see [12] p. 221). Since then I have read Peter Byrne’s biography of Everett, which makes it appear that I may have been wrong about this: according to Byrne, the subtlety which I see as the essence of Everett’s original paper [6] was imposed on him by his thesis adviser, John Wheeler, and what I regarded as extraneous features subsequently added by Bryce de Witt were in fact an essential part of Everett’s vision. I have therefore reverted to an older nomenclature, now generally disapproved, and restored Wheeler’s name to the interpretation I intend