It is generally assumed that Descartes invokes “objective being in the intellect” in order to explain or describe an idea’s status as being “of something.” I argue that this assumption is mistaken. As emerges in his discussion of “materially false ideas” in the Fourth Replies, Descartes recognizes two senses of ‘idea of’. One, a theoretical sense, is itself introduced in terms of objective being. Hence Descartes can’t be introducing objective being to explain or describe “ofness” understood in this sense. Descartes also appeals to a pretheoretical sense of ‘idea of’. I will argue that the notion of objective being can’t serve to explain or describe this “ofness” either. I conclude by proposing an alternative explanation of the role of objective being, according to which Descartes introduces this notion to explain the mind’s ability to attain clear and distinct ideas.