  Agents cannot directly ascribe properties to individuals other than themselves, for all ascription of properties is self-ascription. But under the right conditions, agents can indirectly ascribe properties to objects other than themselves by self-ascribing properties that (roughly speaking) uniquely describe those other objects. For example, suppose that Mary sees Bill and only Bill. She may then self-ascribe the property of seeing exactly one man such that he is hungry. (More precisely, she may self-ascribe the property of being an \(x\) such that there is exactly one \(y\) such that \(y\) is a man and \(x\) sees \(y\) and \(y\) is hungry.) If she does so, then she indirectly ascribes the property of being hungry to Bill, under the relation of being a man uniquely seen. Lewis counts the relation of being a man uniquely seen as an acquaintance relation. According to Lewis, believing a property that uniquely determines an object under an acquaintance relation is sufficient for having a de re belief about that object. So, Lewis would say that Mary de re believes of Bill that he is hungry. But Lewis (1979a) also says “Beliefs de re are not really beliefs,” for he thinks that de re belief is too extrinsic a matter to count as genuine belief.