Observation and quantum objectivity

Abstract

The paradox of Wigner's friend challenges the objectivity of quantumtheory.Apragmatist interpretation can meet this challenge by judicious appeal to decoherence. Quantumtheory provides situated agents with resources for predicting and explaining what happens in the physical world-not conscious observations of it. Even in bizarreWigner's friend scenarios, differently situated agents agree on the objective content of physical magnitude statements while, normally, quantum Darwinism permits agents equal observational access to their truth. Quantum theory has nothing to say about conscious experiences. But it does prompt us to reexamine the significance of everyday claims about the physical world. © 2013 by the Philosophy of Science Association All rights reserved.