Abstract
The difficulty is serious, and unless we find a satisfactory solution we must admit that Descartes' thought moves in a vicious circle, or that the ideas, the building blocks of his philosophy, contain incompatible elements inasmuch as they appear both as self-sufficient and as dependent on extrinsic support. The problem of the cartesian circle, as it is customarily called, is therefore more than a special difficulty and would seem to warrant a careful re-examination in the light of recent contributions to the study of Descartes' philosophy.