Space and the Sense Datum Inference

In this paper I consider the relationship between the spatial properties of visual perceptual experience and the sense-datum inference. I argue that the sense datum inference should be accepted if spatial properties are not merely intentionally present in such experiences. This result serves to underline the seriousness of the difficulties that are presented to direct realism by a particular class of illusory spatial experiences based on the geometry of visual perceptual experience. In light of these considerations I argue that it is a constraint on direct realism that the underlying spatial character of visual perceptual experiences must be the same as that of the physical world.