Sebastian De Haro (University of Amsterdam), Jeremy Butterfield (University of Cambridge)
We have elsewhere advocated a schema for understanding dualities, both in string theory and other fields of physics. In this talk, we use it to address how duality relates to logical equivalence, intertranslatability, of theories. We argue that not all dualities lead to what we call physical equivalence. Indeed, physical equivalence can only obtain, under appropriate conditions, for 'internal interpretations'. These are interpretations that starts from what our schema calls the 'bare theory' i.e. what is common to the two dual theories, ignoring their specific structures.
