 Demarcation. Certain models of unity, which we may call container models, attempt to to demarcate science from non-science. The criteria adopted are typically methodological and normative, not descriptive. Unlike connective models, they serve a dual function of drawing up and policing a boundary that (1) encloses and endorses the sciences and (2) excludes other practices. As noted above, some demarcation projects have aimed to distinguish between natural and special sciences. The more notorious ones, however, have aimed to exclude practices and doctrines dismissed under the labels of metaphysics, pseudo-science or popular knowledge. Empirical or not, the applications of standards of epistemic purity are not merely identification or labeling exercises for the sake of carving out scientific inquiry as a natural kind or mapping out intellectual landscapes.The purpose is to establish authority and the stakes involve educational, legal and financial interests. Recent controversies include not just the teaching of creation science, also polemics over the scientific status of, for instance, homeopathy, vaccination and models of plant neurology and climate change.