Three Comments on Writing the Book of the World
Theodore Sider�s Writing the Book of the World is systematic, wide-ranging, intelligent, and interesting. It is sure to be influential, and deservedly so. Reading it and thinking about it have been a real pleasure. I am certain that I shall return to it again and again.

1. Multifaceted metaphysics

Sider�s book opens with this:
Metaphysics, at bottom, is about the fundamental structure of reality. Not about what�s necessarily true. Not about what properties are essential. Not about conceptual analysis. Not about what there is. Structure. (1)1
But I reply that metaphysics is not � not even �at bottom� � about only one thing, and so not � not even �at bottom� � about only the fundamental structure of reality.

Consider the following claims: free actions cannot be causally determined; true propositions concerning future actions do not preclude freedom; the fundamental bearers of truth and falsity are abstract objects; some properties are universals; all properties are qualitative; persisting objects have temporal parts; a physical object can be wholly located in more than one place at the same time; no two physical objects can be entirely in the same place at the same time; composition is unrestricted; every truth has a truthmaker; propositions are sets of possible worlds; possibly, nothing exists; absences are causally efficacious; each human being is essentially not a chimpanzee.

It is false that every one of these claims, at bottom, is about structure. It is likewise false that there is some other single unified topic that every one of these claims is about. Yet they all are metaphysical claims. Maybe they are all metaphysical because their content is interrelated by �family resemblances�. Or maybe they count as metaphysical not only because of their content, but also in part because of historical accident. Or maybe there is some other explanation. Here �