 Russellian monism is a theory in the metaphysics of mind, on which a single set of properties underlies both consciousness and the most basic entities posited by physics. The theory is named for Bertrand Russell, whose views about consciousness and its place in nature were informed by a structuralist conception of theoretical physics. On such a structuralist conception, physics describes the world in terms of its spatiotemporal structure and dynamics (changes within that structure) and says nothing about what, if anything, underlies that structure and dynamics. For example, as it is sometimes put, physics describes what mass and charge do, e.g., how they dispose objects to move toward or away from each other, but not what mass and charge are. Thus, Russell writes the following about the events physics describes: