Cartesianism is the general philosophical approach of the followers of Descartes. The three major figures in this movement were Malebranche, Geulinex, and Arnauld.
The chief problem raised by the dualism of Descartes is how to account for the actions of men, since here the two substances, mind and matter, must somehow dovetail into a joint system. To this end the Cartesians developed the theory of Occasionalism, according to which an event in the one domain is by divine intervention accompanied by the appropriate event in the other.
In a more general sense, the term Cartesianism is used for certain features typical of Descartes's philosophy, namely the emphasis on the question of how we know things, and on the importance of method.