The issue of the cognitive impenetrability or penetrability of perception lay dormant for a long period of time. Though philosophers reacted to the relativism implied by the work of Hanson, Kuhn, and Feyerabend, they concentrated their efforts in dealing with the danger of the incommensurability of theories. They tried to show by philosophical and detailed historical analysis that scientists within different paradigms do communicate with each other and put their respective theories to the empirical test. Curiously enough the same philosophers did not seek to examine the very foundation of the...