Internalism and the Limits of Twin Earth Scenarios: A Study of Phenomenal Intentionalism explores visual perceptual experiences and whether nor not visual intentional content is internal or external. Coming from the standpoint of phenomenal intentionalism, this book assumes that phenomenal consciousness is internal to the subject of a perceptual experience. Jan Almäng argues that the structure of the phenomenal character of visual experiences sets certain limits with respect to whether Twin Earth thought experiments can be successful, suggesting that while Twin Earth thought experiments are successful for entities such as colours, they fail with respect to more complex geometrical structures. Because visual perceptual experiences represent in an analogue manner, this prevents certain kinds of Twin Earth scenarios from being successful. Almäng then argues that some phenomenal intentional content is internal. If visual experiences have a perspectival structure, that this by necessity means that they are intentional.