The quote makes it obvious that Goodman himself did not consider his constructionalist approach in A Study of Qualities as an epistemological alternative to Carnap’s. Insofar as criticism of a foundationalist epistemology does play a role in The Structure of Appearance or A Study of Qualities, this criticism was rather directed at the philosophy of C.I. Lewis, who was Goodman’s teacher at Harvard. Lewis indeed held the view that empiricism must presuppose the incorrigibility and indubitability of what is given in experience. According to Lewis, I might need to revise, for example, that I saw a plane crossing the sky when I learn that what I mistook for a plane was Superman. However, nothing can make me revise that there was a blue and a red spot in the center of my visual field that then led to the (false) belief that there was a plane.