Title:
Natural kinds, laws, and necessities: lessons from post-Twin-Earth science and philosophy
Abstract:
In a paper co-authored by Genoveva Martí, we defended the Kripke-Putnam thesis that water is necessarily composed of H2O molecules, i.e., that there is no world in which the substance we call ‘water’ exists but is not composed mostly of H2O molecules. But we agree with Putnam that it can be hard to know what to say about imagined possible worlds in which the physical (and hence chemical) laws are different in certain ways. In this talk I will explore some of the speculative ways in which physicists investigate what would be the case in such counternomic worlds, and how these speculations interact with the nature of water and other natural kinds, as well as with powers, dispositions, and other denizens of philosophy-folk physics and chemistry. I will use these explorations to motivate some lessons for debates about the modal status of laws and physical natural