Review of the Topos Approach to Quantum Theory

Topos theory has been suggested by Doring and Isham as an alternative mathematical structure with which to formulate, in general, physical theories. However, the motivation for using it to express quantum theory, lies in the desire to solve certain interpretational problems inherent in the standard formulation of the theory. In fact, the topos approach to quantum theory overcomes the instrumentalist–Copenhagen interpretation, rendering the theory more realist. The caveat is that one ends up with a multivalued–intuitionistic logic, rather than a Boolean logic.