Ideas and Self-Reflection in Leibniz

The term “idea” in the seventeenth century is notoriously difficult. Not only does each major thinker have their own understanding of “idea”—many of those thinkers themselves move ambiguously between different meanings. This confusion is generally attributed to Descartes. While ideas had only existed in the mind of God, Descartes consciously made new use of the term by applying it to things in human minds. At the same time, Descartes left many questions about what an idea is. Given Descartes’ own ambiguity, the various doctrines of ideas developed by Arnauld, Malebranche, Locke, Spinoza and Leibniz, all have some legitimate claim as interpretations of Descartes.