Spinoza on Definition and Essence

The first two chapters of this dissertation address questions concerning Spinoza’s views on the nature of definitions and how they relate to essences. I explain the nature of Spinoza’s distinction between real and stipulative definitions in historical context. I show that the metaphysical assumptions of this distinction explain his criticisms of Giovanni Alfonso Borelli, his unique justification of the notion that stipulative definitions require no defense, and the distinction between definitions and axioms. I also offer a proposal for how this distinction could be further developed in accord with Spinoza’s mature views on ideas and representation in the Ethics. I also construct detailed interpretations and explanations of Spinoza’s criteria for satisfactory definitions, with special attention paid to his adoption of the classical distinction between a thing’s essence and its properties, and to the requirement that definitions include the cause of the thing. In chapters three and four, I demonstrate that Spinoza is committed to the Principle of Unique Causes (PUC), the thesis that each thing has one and only one possible adequate cause. I show that the PUC is independent of Spinoza’s Parallelism and the Principle of Sufficient Reason, and that it follows from his causal axiom (E1a4) when Spinoza’s conception of “involvement” is properly understood. Through an original interpretation of Spinoza’s modal semantics, I show that the PUC is true in virtue of the nature of essences. I argue that it belongs to the essence of each thing to have the specific procreative cause that it does. I refute the most prominent alternative to my interpretation as it emerges from the combined works of Edwin Curley, Michael Della Rocca, and Don Garrett. In the process of doing so, I also develop and defend my own interpretation of the relationship between a thing’s eternal essence and its actual existence, the relationship between essences and the laws of nature, and how essences play a key role in Spinoza’s elusive views on empirical methods