Demarcation can be problematic in cases where standard scientific ways (experiments, logic, etc.) of assessing a theory or a hypothesis cannot be applied for some reason. An example would be of differentiating between the scientific status of metereology or medicine, on the one hand, and astrology, on the other; all these fields repeatedly fail to accurately predict what they claim to be able to predict, and all are able to explain the regular failure of their predictions.

Feyerabend and the Problem of Autonomy in Science

There has been a post-Kuhn trend to downplay the difference between science and non-science, as Kuhn's work largely called to question the Popperian ideal of simple demarcation, and emphasized the human, subjective quality of scientific change. The radical philosopher of science Paul Feyerabend took these arguments to their limit, arguing that science does not occupy a special place in terms of either its logic or method, so that any claim to special authority made by scientists cannot be upheld. This leads to a particularly democratic and anarchist approach to knowledge formation. He claimed that there can be found no method within the history of scientific practice which has not been violated at some point in the advancing of scientific knowledge. Both Lakatos and Feyerabend suggest that science is not an autonomous form of reasoning, but is inseparable from the larger body of human thought and inquiry. If so, then the questions of truth and falsity, and correct or incorrect understanding are not uniquely empirical. Many meaningful questions can not be settled empirically — not only in practice, but in principle.

Thagard's Method

There has been some decrease in interest in the demarcation problem in recent years. Part of the problem is that many suspect that it is an intractable problem, since so many previous attempts have come up short.

For example, many obvious examples of pseudoscience have been shown to be falsifiable, or verifiable, or revisable. Therefore many of the previously proposed demarcation criteria have not been judged as particularly reliable.

Paul R. Thagard has proposed another set of principles to try to overcome these difficulties. According to Thagard's method, a theory is not scientific if it has been less progressive than alternative theories over a long period of time, and faces many unsolved problems; but the community of practitioners makes little attempt to develop the theory towards solutions of the problems, shows no concern for attempts to evaluate the theory in relation to others, and is selective in considering confirmations and disconfirmations.