Abstract

The textbook collapse postulate says that, after a measurement, the quantum state of the system on which the measurement was performed , and becomes an eigenstate of the observable measured. Naively, this is what one would expect of dynamical collapse theories.  What one gets, instead, is an approximation to such eigenstates.  This leaves us with the question of how to interpret such theories as representing a macroscopically definite world.  In this talk, I will review some approaches to the ontology of collapse theories, and raise the question: do these yield rival accounts of the nature of the physical world, or are they mere choices of how to hang talk about ordinary objects onto a theory whose physical import is already clear?