 The correspondence with Des Bosses has thus been taken to provide support for the interpretive thesis that Leibniz’s mature ontology of finite substance countenances the existence of simple substances exclusively (but see Garber 2009 for an opposing view). The correspondence also shows, importantly, that the mere occurrence of the word “corporeal substance” in a text does not immediately imply that Leibniz takes corporeal substances to be substances, strictly speaking. These conclusions might help resolve the apparent tension between Leibniz’s remarks on substance in the Monadologie and the Principes de la Nature et de la Grace. The text of the Monadologie more accurately reflects Leibniz’s considered position because it only characterizes simple substances as “substances”. The Principes de la Nature et de la Grace, in contrast, is less rigorous on this issue (more exoteric) because it uses the term “composite substance” when composites are not substances, strictly speaking (Rutherford 1995: 281–2).