 Peter Strawson's reduplication argument, developed in (1959, 20–22), can be construed as an argument for singular propositions. Strawson used the argument to support the related thesis that demonstrative identification is fundamental to our ability to identify and hence refer to, in speech and thought, individuals. Demonstrative identification of o is enabled by one sensibly discriminating o from other individuals. So one can demonstratively identify only individuals that one has perceived. But one can think about other individuals as well. These further individuals, then, must be descriptively identified. Individuals that one identifies demonstratively are directly identified and not identified in virtue of their satisfies qualities by which the agent conceives the object, as individuals descriptively identified are. (This distinction is reminiscent of Russell's distinction between thought by acquaintance and thought by description. We compare Russell and Strawson in more detail below.) Strawson's notion of demonstrative identification is thus closely related to the notions of direct reference and singular propositions.