Perception, cognition and reasoning about shadows

The way we categorize shadows interfaces with the way we perceive them (Casati,2017). Some thought experiments such as the Yale Problem (Todes & Daniels, 1975), the Intersecting Eclipses Problem (Sorensen,2008), and the Shadow-Light Problem (Casati,2007b) suggest that the conceptual boundaries of shadow phenomena are still not completely explored. To take just the last example, it is conceptually indeterminate whether the green spot that is cast by a green bottle intercepting light is a green light spot or a green shadow (arguments can be put forward to defend either view). Conversely, perceptual double dissociations (some physically impossible shadows are tolerated and some physically correct shadows are seen as awkward) challenge the conceptual system, as in some cases not only there is tolerance, but even preference for impossible shadows