This chapter focuses on the problem of the reference in perception, the problem of the role of action in reference-fixing, and the reference of the theoretical terms of scientific theories. Epistemological constructivism undermines realism by arguing that the experience of the world is mediated by the concepts, and that there is no direct way to examine which aspects of objects belong to them independently of the conceptualizations. Semantic constructivism attacks realism on the ground that there is no direct way to set up the relation between the terms of representations and the entities to which they purportedly refer. For realism to fight back, realists must undermine both epistemological and semantic constructivism. The task of the realist would be to examine the assumptions underlying these two theories of reference, and try to figure out a way to overcome their difficulties by revising or undermining the underlying assumptions.

This chapter is organized around an interdisciplinary understanding of demonstrative reference. It makes two different but mutually supporting points. First, if what we are interested in is the basic principles that the perceptual system employs to isolate an entity and track it over time, then location is not the deep principle. Second, theorizing about perception has been influenced by an unbalanced diet of work specifically on vision, at the expense of research in modalities and multimodal perception. The chapter points out that the ground level at which perception isolates and tracks entities is one below spatial location, material bodies. It addresses the issue of whether spatial location was in any way essentially linked either to perceptual processes that isolate and track objects, or reference to such objects via demonstrative expressions in natural language. The chapter gives an account of the semantics of demonstrative expressions as a semantic category.

This chapter distinguishes three sorts of ideas that play a role in visually guiding action. It argues that vision directly gives awareness concerning certain objects. Austen Clark has constructed a theory in which the content of visual experience consists of visual features attributed to places in a three-dimensional visual field. Clark' s visual features include colour, luminance, relative motion, size, texture, flicker and line orientation. Visual states are about individual things, and this creates a puzzle. Snowdon proposes that when one visually perceives something, he/she is thereby capable of making a demonstrative judgement about it. Neither recollection nor imaging is capable of guiding bodily motion. Snowdon endorses a view known as disjunctivism on the basis of his view about demonstratives. The chapter argues that on-line visual states assign seen objects egocentric locations. It is by means of these location assignments that perceivers act on these objects quickly and accurately.

The claim that perceptual illusions can motivate the existence of sense-data is both familiar and controversial. Admitting that various illusions do not give evidence for sense-data considerably limits the power of the argument from illusion and brings out its distinctness from the argument from perceptual relativity. To reach these conclusions, the chapter examines the role of ambiguity in perception, its connection to illusion, and the link reference to every element of this discourse. The inference from illusions to sense-data has been used to additionally argue for indirect realism, the claim that the immediate objects of perception are always (or at least typically) sense-data. The chapter is concerned with the extent to which a successful form of perceptual reference, what it calls acquaintance, is involved in perceptual awareness. Understanding why some illusions do and some do not support the existence of sense-data is a non-trivial task.

This chapter focuses on the knowledge of the references of perceptual demonstratives: terms like 'this' and 'that' used to refer to currently perceived objects, such as a tree or a person. It has often been remarked, as a basic problem in theory of meaning, that the only credible accounts of meaning are truth conditional, but that it is hard to understand how the functional organization of a subject could constitute their grasp of the truth conditions of the statements they make and the thoughts they have. Functionalism stops short, with a mere characterization of the transitions from content to content one does engage in. In perception we are confronted with the references of perceptual-demonstrative terms, and to that extent we can be said to perceive the intended model for demonstrative discourse. There is an epistemic role for consciousness, for sensory awareness in particular, in our grasp of meaning.