Abstract

This chapter examines a question at the intersection of the mind-body problem and the analysis of mental representation: the question of the direction of constraint between psychological fact and theory and neurophysiological or physical fact and theory. Does physiology constrain psychology? Are physiological facts more basic than psychological facts? Or do psychological theories, including representational analyses, guide and constrain physiology? Despite the antireductionist bent of functionalist positions, it has generally been assumed that physics or physiology are more basic than, and hence contraining on, psychological fact and theory. Section 1 sketches the intuitions that would lead one to adopt such a view. The chapter then examines whether one-sided constraint has been and should be found in practice. It argues that philosophical analysis of psychological science shows that rigorous functional analyses can be carried out in advance of physiological knowledge. Indeed, in the investigation of sensory perception, ascription of psychological function leads the way in the individuation and investigation of neurophysiology. We shall look at several cases in visual perception (binocular single vision, stereopsis, and color vision), in which psychological results have provided a basis for physiological research. It is tempting to think that the psychological functions that enable physiological investigation would be Wrightian teleofunctions. It is, thus, natural to suppose that psychologists and neurophysiologists have proceeded with a conception of the purpose of a given neural structure, and have viewed neural anatomy and neural activity as the substrate for or instantiation of various properly psychological functions. For example, neuroscientists surely understand that the eye and visual system are for seeing, rather than for detecting an electric discharge in the vicinity of the retina (which sighted humans can do, via the subjective light produced by such discharges), and they guide their investigations of the eye, visual cortex, and intervening pathways accordingly. As a result, they will view rods and cones in the eye as photoreceptors, even though these structures will produce "output" (will respond with hyperpolarization) to other forms of energy. At the same time, there may be cases in which the functions that have guided research are in fact precisely determined input-output functions, whose teleofunctional status is absent or misdescribed. I will argue that in the case of trichromatic color matches, the psychological function involved is an input-output function, and that this result has implications for the description of color vision as a psychological capacity.