THE PROJECT OF THE PRINCIPIA

Part I of the Principia covers much the same material that Descartes had already set out in the Meditationes, and Descartes tells one correspondent that ‘it is only an abridgement of what I wrote in the Meditationes’. The Meditationes, however, gives every impression of being self-contained, whereas Part I of the Principia is only one of six Parts of the project as initially envisaged, and effectively forms an introduction to what follows by providing a metaphysical basis for the natural philosophy that is developed there. In understanding the role of Part I in the larger project, it will be helpful to begin by mapping out the dangers, as we will have to steer a path through the Charybdis of treating the remainder of the Principia as an appendage to Part I, and the Scylla of treating Part I as a redundant introduction to the remainder.

If the Meditationes is as self-contained as it appears, we must ask what the purpose of the Principia is. Certainly, on one widespread reading of the Meditationes, the real novelty and originality of Descartes' project consist in his showing, by means of a project of radical doubt, the need for foundations for knowledge, and then providing these foundations, so that we might reconstruct anew the world that Meditation I called into doubt.