Abstract

The question, how is profound intellectual disagreement possible, even when addressed toward the paradigmatically reasonable activity of scientific communication, has generated a number of puzzling responses. On a response attributed to Thomas S. Kuhn, some episodes in the history of science don't allow for meaningful disagreement. In such situations, the adversaries talk at cross purposes until one side is either "converted" or dies off. ;This skeptical prospect has also been considered by those who study the differences between natural languages, and the misunderstandings which punctuate a child's first language acquisition. I investigate theories of concepts in search of one capable of illuminating the apparent gaps in communication between scientists, between speakers of different languages, and between infants and adults. I begin by showing that the antipsychologist efforts of post-Fregean philosophers of language, in particular those built on a causal theory of reference, fail to explain either how communication is possible when it is, or why it isn't otherwise. Nor does recourse to a principle of charity or humanity help them in this regard. I conclude that such attempts can't ground an account of communication. ;I argue that an account of concept learning drawn in part from recent work in developmental psychology can explain both the possibility of serious disagreement, as well as the possibility of overcoming it reasonably. I urge that the revival of psychologism in the philosophy of language follows. Semantic psychologism is semantics informed by empirical psychology, not by the phenomenology Frege attacked. I explore the consequences of this doctrine for the philosophy and history of science. These include a rejection of the common philosophical assumption that all meaningful communication can be reduced to a form of translation, and renewed emphasis on the importance of analogy in communication. ;Finally, I apply this new semantic psychologism toward the historical interpretation of science. If the program is right, it should provide insight into the communicative dimensions of important episodes in the history of science. While a full exploration of this historical method lies beyond the scope of my thesis, two preliminary case studies indicate its fruitfulness