  On the existential reading, knowledge is set over what exists; belief is set over what exists and does not exist. On the predicative reading, knowledge is set over Forms, what is F, for any property F (or some privileged kinds of properties, e.g. incomplete properties); belief is set over what is F and not-F, the material particulars. The existential and predicative readings typically are committed to objects as what knowledge and belief are set over. Since it is hard to make sense of what it could be for an object to exist and not exist, the existential reading has found little support. (There are other objections to an existential reading, principally that many think that Plato never works with an ‘is’ of existence (see Owen 1986c).