Parts | Days | Selection | Search | Downloads | Help

AKPhil: Arbeitskreis Philosophie der Physik

AKPhil 7: Interpretations of Quantum Theory 2

AKPhil 7.1: Talk

Thursday, March 8, 2007, 16:45–17:15, KIP SR 3.401

Classical physics and classical logic in Quantum Mechanics — •Manuel Bächtold — Institut für Philosophie, Fakultät 14, Dortmund Universität, D-44221 Dortmund

Are the measurement outcomes in microphysics ``classical"? If yes, in which sense? In this talk, I will come back to Niels Bohr's interpretation of quantum mechanics and his claim that every measurement outcomes have to be described by means of classical physics. Carl Friedrich von Weizsäcker's transcendental version of this claim and its recent justification provided by Brigitte Falkenburg will also be discussed. I will then support the idea that a measurement outcome in microphysics cannot be considered as ``classical" because its occurrence would be governed by the deterministic laws of classical physics (indeed, in the general case, it can only be predicted in a probabilistic manner by quantum mechanics). It can be considered as ``classical", I will argue, only by reference to classical logic. It is true, when no measurement is performed, the structure of propositions expressing all the possible events conforms to a kind of quantum logic (e.g. partial Boolean algebra or orthomodular lattice). However, if considering a performed measurement, the propositions expressing its possible outcomes (i.e. ``possible" according to the predictions of quantum mechanics) are characterized as follows: at the end of the measurement (i) each of these propositions is either true or false (principle of bivalence), and (ii) only one of these propositions is true (principle of mutual exclusiveness).