[9] Medical writers of the Hippocratic tradition maintained that their discussions were based on demonstration of logical necessity, a theme developed by Aristotle in his Posterior Analytics.
[10] One element of this polemic for science was an insistence on a clear and unequivocal presentation of arguments, rejecting the imagery, analogy, and myth of the old wisdom.
[12] Cicero's De Divinatione implicitly used five criteria of scientific demarcation that are also used by modern philosophers of science.
[14] Ayer, a member of the Vienna Circle and a noted English logical-positivist, argued that making any statements about the world beyond one's immediate sense-perception is impossible.
Popper's demarcation criterion has been criticized both for excluding legitimate science ... and for giving some pseudosciences the status of being scientific ...
According to Larry Laudan (1983, 121), it "has the untoward consequence of countenancing as 'scientific' every crank claim which makes ascertainably false assertions".
[19]Popper argued that the Humean induction problem shows that there is no way to make meaningful universal statements on the basis of any number of empirical observations.
[19] Kuhn's work largely called into question Popper's demarcation, and emphasized the human, subjective quality of scientific change.
Both Imre 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.
[citation needed] Paul R. Thagard proposed another set of principles to try to overcome these difficulties, and argued that it is important for society to find a way of doing so.
His definition is a practical one, which generally seeks to distinguish pseudoscience as areas of inquiry which are stagnant and without active scientific investigation.
He also stated that demarcation criteria were historically used as machines de guerre in polemical disputes between "scientists" and "pseudo-scientists".
[28] Ian Hacking, Massimo Pigliucci, and others have noted that the sciences generally conform to Ludwig Wittgenstein's concept of family resemblances.
[6] Anthropologist Sean M. Rafferty of the University at Albany, SUNY in his text Misanthropology: Science, Pseudoscience, and the Study of Humanity contrasts science and pseudoscience within his discipline thusly:[E]ven for those subfields where there is a significant element of interpretation, those interpretations are still based on and constrained by physical evidence.
[33]: 220 Discussions of the demarcation problem concern the rhetoric of science and promote critical thinking, which is important for democracy.
[6]: 35 For example, Gordin stated: "Demarcation remains essential for the enormously high political stakes of climate-change denial and other anti-regulatory fringe doctrines".
[33]: 225 Philosopher Herbert Keuth [de] noted: Perhaps the most important function of the demarcation between science and nonscience is to refuse political and religious authorities the right to pass binding judgments on the truth of certain statements of fact.
[34]Concern for informed human nutrition resulted in the following note in 1942: If our boys and girls are to be exposed to the superficial and frequently ill-informed statements about science and medicine made over the radio and in the daily press, it is desirable, if not necessary, that some corrective in the form of accurate factual information be provided in the schools.
Although this is not a plea that chemistry teachers should at once introduce the study of proteins into their curricula, it is a suggestion that they should at least inform themselves and become prepared to answer questions and counteract the effects of misinformation.