Cordemoy’s argument for occasionalism with regard to body-body interaction appears in the Fourth Discourse of the Discernement (he will later expand his occasionalism to cover all ‘interaction’ in the created world). There we are given a series of definitions and axioms, and conclusions derived from these. Cordemoy begins by asserting as axioms (1) a thing does not have of itself (de soy) that which can be lost without ceasing to be what it is, and (2) bodies are able to lose their motion withou