title: Reply to Philipona and O'Regan.
abstract: This paper responds to Philipona and O'Regan (2006), which attempts to account for certain color phenomena by appeal to singularities in the space of "accessible information" in the light striking the retina. Three points are discussed. First, it is unclear what the empirical significance/import is of the mathematical analysis of the data regarding the accessible information in the light. Second, the singularity index employed in the study is both mathematically and empirically faulty. Third, the connection drawn between their findings and some data from the World Color Survey is lacking in quantitative analysis in places where it is needed. The difficulties raised prevent Philipona & O'Regan's conclusions from being accepted.
authors.affiliation: Department of Logic and Philosophy of Science, University of California, Irvine, California, USA.
authors.forename: Kent
authors.initials: K
authors.lastname: Johnson
authors.forename: Wayne
authors.initials: W
authors.lastname: Wright
mesh_terms: D003118:Color Perception / Q000502:physiology*; D006801:Humans; D008027:Light; D008960:Models, Psychological; D025341:Principal Component Analysis; D012160:Retina / Q000528:radiation effects*; D012542:Scattering, Radiation