Thompson Clarke’s paper marked the beginning of the revival of the interest to the problems of philosophical skepticism in the early 70’s. In his paper Clarke raises the issue of skepticism’s relevance to the philosophical inquiry and provides a new interpretation of the traditional skeptical problems. Also Clarke points out the significance of G. E. Moore’s defense of common sense. Particularly, he shows that the lack of ordinary contexts does not make skeptical questions and Moore’s attempts to answer these questions are meaningless, as philosophers of ordinary language claimed. However, skeptics and their opponents usually share a theoretical presupposition - the idea of standard human-conceptual constitution. As Clarke points out, this constitution supposedly determines the limits and content of the human knowledge about the world. The notion of objective knowledge and the conception of philosophy itself are based on the idea of such a constitution. However, Clarke, by applying the concepts of dream and hallucination, illustrates that this idea contradicts the functioning of the concepts we use to learn about and understand the world.