The question of this paper can be put roughly as follows. For Shepherd, how many things exist? On the one hand, it looks like the answer is going to be: many! It is a central tent of Shepherd’s philosophical system that causation is a relation whereby two or more objects combine to create a third. Since there are many instances of this causal relation, there must be many objects in the world. Add to this the distinction between internal (mental) objects and external ones, and the distinction between these and the divine essence that is the cause of all the others, and it seems like there sure are a lot of things in the universe. On the other hand, though, there are several moments throughout her writing where Shepherd indicates that the distinction between causes and effects is in some sense unreal. For example, in ERCE she claims that, “Cause and Effect are […] but different words for the same Essence”(ERCE 57), and in EPEU that, “all things in a strictly philosophical sense, form ONE NATURE”(EPEU 359). In these texts, it looks like Shepherd is saying that while the world appears to us to consist of many distinct objects interacting causally, really there is just one thing and its merely nominally distinct parts. So which is it?
My suggestion is that Shepherd is an ontological pluralist, and the texts that appear to express a commitment to ontological monism are best understood as expressing ontological holism instead. That is, Shepherd holds that each of the many objects that exist has its own essence, but that theses essences necessitate certain relational facts about them—how they combine with other objects to bring about new ones. As such, for each object to be the object that it is, implies that it occupies a role in a system of causally-related objects that together form one world. That holism, rather than monism, is the sense in which “cause and effect are but different words for the same essence” and “all things form one nature”. My process here is as follows. First, I present the case for considering Shepherd an ontological pluralist. Then, I present the case for considering her an ontological monist. After considering some related texts, I conclude that Shepherd is, in fact, an ontological holist. I then reread the monism-implying texts from that perspective, and also present other texts which support the holism interpretation.