John Kulvicki

Problems concerning scientists’ uses of representations have received quite a bit of attention recently. The focus has been on how such representations get their contents and on just what those contents are. Less attention has been paid to what makes certain kinds of scientific representations different from one another and thus well suited to this or that epistemic end. This article considers the latter question with particular focus on the distinction between images and graphs on the one hand and descriptions and related representations on the other. *Received January 2008; revised September 2009. †To contact the author, please write to: Department of Philosophy, Dartmouth College, Hanover, NH 03755; e‐mail: [email protected].

Analog representation is often cast in terms of an engineering distinction between smooth and discrete systems. The engineering notion cuts across interesting representational categories, however, so it is poorly suited to thinking about kinds of representation. This paper suggests that analog representations support a pattern of interaction, specifically open-ended searches for content across levels of abstraction. They support the pattern by sharing a structure with what they represent. Continuous systems that satisfy the engineering notion are exemplars of this kind because they are uninterpretable unless they are structure-preserving. Analog representations, so understood, include pictures, images, diagrams, and most graphs. This conception of analogicity also fits well with a line of thought about what makes perceptual states distinctive: they satisfy a “parts principle”

There are undeniably many ways of depicting things, but it is unclear what the diversity of depictive representational systems consists in. What is a way of depicting something, and how many ways of depicting things are there? Pictorial diversity starts to seem interesting and confusing when one tries to fix a picture's content while varying its surface features, or vice versa. This chapter seeks to explain what is at issue in discussing pictorial diversity and to introduce two tools for understanding it: the notions of syntactic competition and semantic competition. The fact that pictures compete neither syntactically nor semantically places important constraints on picture interpretation.

For the information theorist, the lawful generalizations that subsume instantiations of properties in the environment and instantiations of properties of perceptual representations determine the latter's content. Perceptual representations are also commonly thought to be isomorphic to what they represent, which presents the information theorist with a puzzle. What role could isomorphism play in perceptual representation when lawful generalizations determine content? I show that in order for the information that they carry to be available to cognition, perceptual representations must be isomorphic with respect to the constituent structure of the properties that they represent. Isomorphism therefore plays an important role in the information theorist's account of perceptual representation, even though it plays no role in determining content.

There is a growing consensus in the philosophical literature that sounds differ rather profoundly from colors. Colors are qualities, while sounds are particulars of some sort or other, such as events or pressure waves. A key motivation for this is that sounds seem to be transient, to evolve over time, to begin and end, while colors seem like stable qualities of objects' surfaces. I argue that sounds are indeed, like colors, stable qualities of objects. Sounds are not transient, and they do not seem to be, even though they are typically perceived transiently. In particular, sounds are dispositions of objects to vibrate in response to being stimulated. This stable property view of sounds aligns nicely with, and owes an inspirational debt to, reflectance physicalist accounts of color. The upshot is a unified picture of colors, sounds, and the perception thereof.

Our perceptual systems make information about the world available to our cognitive faculties. We come to think about the colors and shapes of objects because we are built somehow to register the instantiation of these properties around us. Just how we register the presence of properties and come to think about them is one of the central problems with understanding perceptual cognition. Another problem in the philosophy of perception concerns the nature of the properties whose presence we register. Among the perceptible properties are colors and shapes, for example, and there is a long philosophical tradition of drawing and refusing to draw metaphysical distinctions between them. This paper makes a claim about the information-theoretic approach to perceptual cognition in order to argue for a fundamentally epistemological distinction between colors and shapes. What makes shapes and colors seem so different to us is how we carry information about their presence around us. In particular, we can come to know more about the shapes on the basis of perceiving them than we can come to know about the colors. One interesting feature of how this distinction is drawn is that it partially vindicates Locke’s claim that our ideas of primary qualities like shapes resemble them in ways our ideas of colors do not