If asked what Humeanism could mean today, there is no other philosopher to turn to whose work covers such a wide range of topics from a unified Humean perspective as that of David Lewis. The core of Lewis's many contributions to philosophy, including his work in philosophical ontology, intensional logic and semantics, probability and decision theory, topics within philosophy of science as well as a distinguished philosophy of mind, can be understood as the development of philosophical position that is centered around his conception of Humean supervenience. If we accept the thesis that it is physical science and not philosophical reasoning that will eventually arrive at the basic constituents of all matter pertaining to our world, then Humean supervenience is the assumption that all truths about our world will supervene on the class of physical truths in the following sense: There are no truths in any compartment of our world that cannot be accounted for in terms of differences and similarities among those properties and external space-time relations that are fundamental to our world according to physical science.

Drawing together his work from four decades, Phillip Bricker provides a comprehensive account of modal reality - the realm of possible worlds - from a Humean perspective, with excursions into neighboring topics in metaphysics. Many of the chapters in this volume focus on aspects of David Lewis's metaphysics and his defence of modal realism, sometimes further developing and defending Lewis's views, sometimes deviating from them in substantial ways. The volume is presented in four parts: part one sketches an account of reality as a whole, both the mathematical and the modal, defending a form of plenitudinous realism; part two presents and defends a realist theory of concrete possible worlds with an absolute ontological distinction between the actual and the merely possible; part three presents and defends a Humean account of modal plenitude, formulating and endorsing principles that guarantee a plenitude of recombination, of possible structures, and of alien contents; and part four applies the Humean account to truthmaking, mereology, spacetime, and quantities. An uncompromising Humean, Bricker shows that holding fast to Humean strictures leads to views that differ in radical ways from those prevalent among contemporary metaphysicians.