Thomas Barrett (University of California, Santa Barbara)
My aim in this talk is to demonstrate that the following two questions are closely related. The question of content: What is the content of a physical theory? The question of equivalence: When should we consider two theories to be equivalent? I will argue that we can approach the former question by way of the latter. In slogan form, one might put this suggestion as follows: We go a long way towards pinning down what the theory "says about the world" by pinning down which other theories "say the same thing."
