This chapter discusses problems of demarcation of science, of pseudo-science, and of metaphysics, mainly to dispel some vulgar errors concerning metaphysics (namely the identification of it with pseudo-science) and its role in the scientific tradition. It argues that metaphysics can progress—not so much in order to defend metaphysics as to expound view of metaphysics as a coordinating agent in the field of scientific research. Since there are more scientific problems to be studied than researchers to study them, a complete avoidance of overlap between projects is quite possible. The existence of a variety of problems to be solved, and the fact that newcomers to science have a great variety of reasons which draw them to science, would by itself render science almost Crusonian. Most philosophers and historians of science would vehemently oppose this view. Descartes, as is well known, developed a philosophical theory in which metaphysics provides the framework for science.