 Descartes took there to be three “levels” of formal reality: the level of infinite substance, the level of finite substance (as defined by its principal attribute), and the level of mode. The level of formal reality of an infinite substance is greater than that of a finite substance, and the level of formal reality of a finite substance is greater than that of a mode. This is understood in terms of ontological dependence. A mode depends for its formal reality on the formal reality of a finite substance, and a finite substance depends for its formal reality on the formal reality of an infinite substance. An existent idea, in possessing the level of formal reality of a mode, is less “real” than a finite substance, which is in line with what was said in the previous section of this entry. 