This dissertation examines representationalism about sensory phenomenology—the claim that for a sensory experience to have a particular phenomenal character is a matter of it having a particular representational content. I focus on a particular issue that is central to representationalism: whether reductive versions of the theory should be internalist or externalist. My primary goals are (i) to demonstrate that externalist representationalism fails to provide a reductive explanation for phenomenal qualities, and (ii) to present a reductive internalist version of representationalism that utilizes the empirical framework of psychophysics and neuroscience to develop a philosophical theory of content. The bulk of the project is an attempt to pr...