 This brings us to yet another objection, concerning the ontology of ideas in God. Following Descartes, Malebranche proclaims throughout his work that everything that exists is either a substance or a modification of a substance. Thus, it would seem that if ideas are in God then they too must be either substances in their own right or divine modifications. Malebranche explicitly denies the latter, for God is immutable and thus ‘incapable of modifications’ (Elucidation 10, OC 3:149; LO 625). But they cannot be substances either for that would violate the theological doctrine that God is perfectly simple (more on this below). Malebranche, it would appear, is forced to abandon his substance-mode ontology: ‘I believe that intelligible extension is neither a substance nor a modification of substance, notwithstanding the axiom of the Philosophers [that everything is a either a substance or a mode]’ (OC 6:245). One must be careful, however, not to read this remark as conceding defeat, for in the continuation of this reply to Arnauld and in the passage above, he identifies ideas with God’s substance: ‘God’s ideas of creatures are … only His essence, insofar as it is participable or imperfectly imitable’ (Elucidation 10, OC 3:149; LO 625). Perhaps Malebranche is not inconsistent after all for, as it turns out, ideas are substances, just not distinct substances. They are God’s substance conceived of in a certain way. The problem, unfortunately, goes beyond the issue of whether Malebranche is inconsistent. We are never given a clear account of the ontology of ideas; even in identifying them with God he must rely on the Platonic metaphor of participation.