Cartesian Truth

Abstract Written in the tradition of analytic reconstruction, Cartesian Truth provides a systematic reinterpretation of central themes in Descartes's epistemology, metaphysics and ontology, theory of perception, both philosophical and empirical, logic, and doctrine of method. For example, it shows how the intuitive and syllogistic aspects of the cogito relate to one another and that Descartes's case for substance dualism depends on the intuitive cogito. It further argues that Descartes employs a single pattern of reasoning based on the ”rule of truth” in all of his major existential proofs, including the proofs of his own existence, God, and the external world; that the rule of truth can be regarded as a conservative extension of the intuitive cogito. Grounded in a reinterpretation of the theory of ideas and Descartes's notion of cause, a case is made that the causal principle of the objective reality of our ideas can be regarded as a reformulation of the rule of truth. The book also provides a detailed reconstruction of Descartes's doctrine of sense perception, including the difficult doctrine of the material falsity of ideas of the senses (”secondary qualities”) but also arguing that Descartes countenances a phenomenological dimension to the sense experience of primary qualities that he attributes to the faculty of imagination, and that the phenomenology is influenced by reasoning and undergoes development from the experience of the child to that of the adult. A case is made that the phenomenology of experience provides material for the systematic errors of commonsense; but a case is also made that the senses and the imagination provide not only material for error but a sensory foundationalism expressed in the notion (explicitly formulated for the first time in the Principles of Philosophy) of clear but not distinct ideas of the senses. An error theory is an important tool in the inventory of revisionary philosophers, more dialectically potent than Descartes's method of doubt as traditionally understood. In the context of contemporary epistemology, the author shows how Cartesian error theory can function as part of a notion of epistemic responsibility in an effective method for dealing with claims of dogmatic opponents, in a way well illustrated by Descartes's own use of the method against his scholastic and commonsense realist opponents.