 Various proposals have been put forward on exactly what elements in science or pseudoscience criteria of demarcation should be applied to. Proposals include that the demarcation should refer to a research program (Lakatos 1974a, 248–249), an epistemic field or cognitive discipline, i.e. a group of people with common knowledge aims, and their practices (Bunge 1982, 2001; Mahner 2007), a theory (Popper 1962, 1974), a practice (Lugg 1992; Morris 1987), a scientific problem or question (Siitonen 1984), and a particular inquiry (Kuhn 1974; Mayo 1996). It is probably fair to say that demarcation criteria can be meaningfully applied on each of these levels of description. A much more difficult problem is whether one of these levels is the fundamental level to which assessments on the other levels are reducible. However, it should be noted that appraisals on different levels may be interdefinable. For instance, it is not an unreasonable assumption that a pseudoscientific doctrine is one that contains pseudoscientific statements as its core or defining claims. Conversely, a pseudoscientific statement may be characterized in terms of being endorsed by a pseudoscientific doctrine but not by legitimate scientific accounts of the same subject area.