Dr. Halpin is attempting to show how physical theory, and quantum mechanics in particular, can act as a guide to counterfactual logic. Counterfactuals are statements about what would happen if, counter to fact, certain circumstances held. Included amongst counterfactuals are important interpretative statements in quantum mechanics about what would result and with what probability if a measurement were to be performed. Over the past several years, Dr. Halpin has developed various negative consequences of physical theory for counterfactual logic. A number of influential counterfactual theories are inadequate, he has shown, given basic facts of physics. In contrast and more positively, reasoning from the physics also supports a new approach to the similarity analysis of counterfactuals. It is this approach and its motivation which Dr. Halpin is examining. Much of this research is specific to counterfactuals within the quantum mechanical context. This research includes the development of the logic of a probabilistic counterfactual meant to explicate quantum mechanical probability attribution.
