The problem of the unity of the proposition is almost as old as philosophy itself, and was one of the central themes of early analytical philosophy, greatly exercising the minds of Frege, Russell, Wittgenstein, and Ramsey. The problem is how propositions or meanings can be simultaneously unities (single things) and complexes, made up of parts that are autonomous of the positions they happen to fill in any given proposition. The problem has been associated with numerous paradoxes and has motivated general theories of thought and meaning, but has eluded any consensual resolution; indeed, the...