This volume is a companion to my book on Malebranche insofar as it draws attention to the variety of Cartesianisms that emerged after the death of Descartes. Indeed, the two main protagonists here – Desgabets and Regis – were mentioned in the earlier text, which cited their discussion of the cogito and the nature of mind to illustrate what is by contrast the more orthodox Cartesian perspective on these issues in Malebranche. Upon reflection, however, I was not completely satisfied with what I said there about Desgabets and Regis, particularly with respect to their development of Descartes's doctrine of the creation of the eternal truths. I also was puzzled by their serene confidence in their seemingly implausible thesis, which I all but ignored in the Malebranche book, that the mere fact that we have ideas of extra-mental objects suffices to show that such objects exist.

For these reasons, I decided to return to Desgabets and Regis and, starting from the beginning, to attempt to better understand their unusual and intriguing form of Cartesianism. The result is this study, which retains the emphasis in the Malebranche book on the “radical” nature of their philosophical psychology. Yet there is the additional claim that their views in this area have a significant Cartesian basis. Moreover, this study includes the thesis that the account of the eternal truths in Desgabets and Regis indicates an important sense in which their system is closer to Descartes's than is that of Malebranche.