As we saw in Chapter 1, Lewis is prepared to try to locate everything we come across in a single, physical, realm. Lewis goes even further. Not only is everything in our world to be accounted for in physical terms, but he is also spartan when it comes to accounting for the physical world. For Lewis, many physical objects are not themselves fundamental, but are composed of smaller and less long-lived objects. At the fundamental level, Lewis is prepared to describe the world as an arrangement of instantaneous, point-sized instantiations of perfectly natural qualities: a “mosaic” of “local, particular matters of fact” (Lewis 1986b: ix). The only fundamental relations between different pieces of this mosaic are spatiotemporal ones (“being-one-metre-away-from” is an example of a spatiotemporal relation, although not necessarily one of the most basic ones), and from this arrangement of point–instant-sized qualities, Lewis proposes to provide us with a metaphysics that will be adequate to include everything we find in the world: bicycles, galaxies, orchestras, debates, fashion shows, colours, wars, values, and so on. A rich outcome from a limited basis!

This world and the Humean mosaic

Lewis gives the name “Humean supervenience” to the view that “all there is to the world is a vast mosaic of local matters of particular fact, just one little thing and another” (1986b: ix). The “Humean” comes from David Hume, who is associated with the view that all there is in the world are regularities of occurrence, without any necessary connections between them.