A Study of Qualities, on the other hand, begins with the argument that even the simplest judgments of this sort—as the one about a blue and a red spot in the center of my visual field—might be revised in the light of new evidence. My judgment that I had a blue spot in the middle of my visual field a few seconds ago when I looked at a ripe apple under normal conditions might be revised when I now judge that I have a red spot in my visual field, looking at the same object under the same conditions and know that it could not have changed its color. However, if such revisions can be made in retrospect, nothing of the “given” is indubitable or incorrigible. Judgments about qualia, in this sense, are decrees; which judgments are accepted is a matter of the overall coherence of my system of beliefs and my other qualia judgments. 