Abstract

There are two main objectives in this chapter: to give a preliminary formal statement of the inference from my ideas to the existence of things outside my ideas in Descartes's epistemology, and to develop the main outlines of Cartesian ontology and the theory of ideas. Key notions discussed are those of truth, possibility, existence, and related notions; representation of ideas, and formally and eminently contained properties in substances; the ontological status of immutable essences and eternal truths. Among contentions made in this chapter about Cartesian ontology is that essences are contained in the mind not as modes but as quasi‐platonic entities, that there is in Descartes's theory of ideas, a general difference between the objects of ideas and the mode of presentation of the objects that holds even when the objects are essences; and that this difference leads to an epistemic rather than a causal account of the distinction between formal and eminent containment.