(2012) Supervenience: From Synchronic to Diachronic

Abstract

Lecture in Bergen 2012, Mar. 9. Supervenience has been summarized as "No difference without a physical difference." Synchronic supervenience has been widely discussed and debated-the view that at a given time, the distribution of, say, moral or mental properties in a given world cannot differ from the distribution of moral or mental properties in another world unless there is a difference in the distribution of natural or physical properties between the worlds. But diachronic supervenience has been much less discussed and hardly debated at all-the view that the distribution of, say, moral or mental properties in a world cannot change through time unless there is a change in the distribution of natural or physical properties in that world over time. What is there to discuss or debate? It has seemed obvious that this, or something very like it, must be true, and indeed, may well follow from synchronic supervenience. I will several examples to argue that diachronic supervenience is not as obvious as it seems. These examples raise questions about the appropriateness of "possible worlds semantics" for understanding supervenience, the relevance of conceptual change, and the prospects for realism about the moral and the mental.