UC San Diego

This project has as its focus a pair of related phenomena central to human perception. The first is the underdetermination of perceptual content by sensor input, and the second is a class of mechanisms designed to transform impoverished sensor input into useful perceptual content, mechanisms commonly called `perceptual constancies'. The goal of this project is to discuss a particularly difficult form of sensory underdetermination I call \textit{stacking}, a \textit{co-local} sensory conflation of distal properties like surface color and illumination, or size and distance. And although stacking problems are not computationally intractable, there appear to be significant constraints on potential solutions to these problems, constraints rooted in the phenomenal structure of perceptual experience. Accordingly, I spend much of the project examining in detail a type of intentional content I argue explains the phenomenology of perceptual experience---\textit{phenomenal content}. With explanatory adequacy as a guiding principle, I argue that phenomenal contents cannot be indeterminate, in the sense that they cannot fail to be attributional. I also argue that phenomenal contents must be \textit{phenomenally bounded}, a conclusion that rules out of consideration various high-level properties like natural kinds. Additionally, I argue that there are in fact two distinct domains of phenomenal content. The first I call the \textit{energy map}, as its contents are tied closely to the distribution of energy across the sensors. The second I call the \textit{worldmaker}, as its contents are what make the world accessible and intelligible to perceivers. Worldmaker contents are underdetermined by energy map contents and are a phenomenal manifestation of perceptual mechanisms of \textit{overreach}, the general term for solutions to problems of sensory underdetermination. After setting up these constraints, I apply them to the problem of color constancy, and I argue that the standard view of color constancy, found both in philosophy and in perceptual psychology---the view that we perceptually represent spectral surface reflectance---must be wrong. My methodology and conclusions have implications both for philosophical accounts of perception and for computational models of perception.