Metaphysical Preliminaries

The book argues that objective chance facts are grounded on the existence of patterns in the events found in our world’s Humean Mosaic (HM); and the chance facts so grounded will later be seen to be apt for guiding rational credences (subjective probabilities) in the way captured by the Principal Principle (PP). But what is this HM? What does it contain, and what does it leave out? What understanding of time is presupposed? The rest of the chapter discusses the idea of considering objective chance facts to be primitives of some sort, as most propensity views hold, or to be based on primitively (irreducibly) chancy laws of nature. After an extended attempt to explore what it could mean to postulate primitive chances or chancy laws, it is argued that no acceptable answer can be given. A tacit invocation of PP helps explain why philosophers often think they understand the meaning of primitive chance claims. The invocation of the PP is illegitimate, though, because there is no way to show that a bare primitive posit deserves to guide credence in the way captured by PP.