In philosophy of science and epistemology, the demarcation problem is the question of how to distinguish between science and non-science. [1] It also examines the boundaries between science, pseudoscience and other products of human activity, like art and literature and beliefs. [2] [3] The debate continues after more than two millennia of dialogue among philosophers of science and scientists in various fields. [4] [5] The debate has consequences for what can be termed "scientific" in topics such as education and public policy. [6] : 26, 35
An early attempt at demarcation can be seen in the efforts of Greek natural philosophers and medical practitioners to distinguish their methods and their accounts of nature from the mythological or mystical accounts of their predecessors and contemporaries. [7]
Aristotle described at length what was involved in having scientific knowledge of something. To be scientific, he said, one must deal with causes, one must use logical demonstration, and one must identify the universals which 'inhere' in the particulars of sense. But above all, to have science one must have apodictic certainty . It is the last feature which, for Aristotle, most clearly distinguished the scientific way of knowing. [2]
— Larry Laudan, "The Demise of the Demarcation Problem" (1983)
G. E. R. Lloyd noted that there was a sense in which the groups engaged in various forms of inquiry into nature attempt to "legitimate their own positions", [8] laying "claim to a new kind of wisdom ... that purported to yield superior enlightenment, even superior practical effectiveness". [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. [11] Some of their claimed naturalistic explanations of phenomena have been found to be quite fanciful, with little reliance on actual observations. [12]
Cicero's De Divinatione implicitly used five criteria of scientific demarcation that are also used by modern philosophers of science. [13]
Logical positivism, formulated during the 1920s, is the idea that only statements about matters of fact or logical relations between concepts are meaningful. All other statements lack sense and are labelled "metaphysics" (see the verifiability theory of meaning also known as verificationism).
According to A. J. Ayer, metaphysicians make statements which claim to have "knowledge of a reality which [transcends] the phenomenal world". [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. [15] This is because even metaphysicians' first premises will necessarily begin with observations made through sense-perception. [15]
Ayer implied that the demarcation occurs when statements become "factually significant". [15] To be "factually significant", a statement must be verifiable. [15] In order to be verifiable, the statement must be verifiable in the observable world, or facts that can be induced from "derived experience". [15] This is referred to as the "verifiability" criterion. [15]
This distinction between science, which in the opinion of the Vienna Circle possessed empirically verifiable statements, and what they pejoratively termed "metaphysics", which lacked such statements, can be considered as representing another aspect of the demarcation problem. [16] Logical positivism is often discussed in the context of the demarcation between science and non-science or pseudoscience. However, "The verificationist proposals had the aim of solving a distinctly different demarcation problem, namely that between science and metaphysics." [17]
Karl Popper considered demarcation as a major problem of the philosophy of science. Popper articulates the problem of demarcation as:
The problem of finding a criterion which would enable us to distinguish between the empirical sciences on the one hand, and mathematics and logic as well as 'metaphysical' systems on the other, I call the problem of demarcation." [18]
Falsifiability is the demarcation criterion proposed by Popper as opposed to verificationism: "statements or systems of statements, in order to be ranked as scientific, must be capable of conflicting with possible, or conceivable observations." [19]
Popper rejected solutions to the problem of demarcation that are grounded in inductive reasoning, and so rejected logical-positivist responses to the problem of demarcation. [18] He argued that logical-positivists want to create a demarcation between the metaphysical and the empirical because they believe that empirical claims are meaningful and metaphysical ones are not. Unlike the Vienna Circle, Popper stated that his proposal was not a criterion of "meaningfulness".
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". Astrology, rightly taken by Popper as an unusually clear example of a pseudoscience, has in fact been tested and thoroughly refuted ... Similarly, the major threats to the scientific status of psychoanalysis, another of his major targets, do not come from claims that it is untestable but from claims that it has been tested and failed the tests. [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. [20] Therefore, empirical statements are no more "verifiable" than metaphysical statements.
This creates a problem for the demarcation the positivists wanted to define between the empirical and the metaphysical. By their very own "verifiability criterion", Popper argued, the empirical is subsumed into the metaphysical, and the demarcation between the two becomes non-existent.
In Popper's later work, he stated that falsifiability is both a necessary and sufficient criterion for demarcation. He described falsifiability as a property of "the logical structure of sentences and classes of sentences", so that a statement's scientific or non-scientific status does not change over time. This has been summarized as a statement being falsifiable "if and only if it logically contradicts some (empirical) sentence that describes a logically possible event that it would be logically possible to observe". [19]
Thomas Kuhn, an American historian and philosopher of science, is often associated with what has been termed postpositivism or postempiricism. In his 1962 book The Structure of Scientific Revolutions , Kuhn divided the process of doing science into two different endeavors, which he termed normal science and extraordinary science (sometimes known as "revolutionary science"), the latter of which introduces a new "paradigm" that solves new problems while continuing to provide solutions to the problems solved by the preceding paradigm. [19]
Finally, and this is for now my main point, a careful look at the scientific enterprise suggests that it is normal science, in which Sir Karl's sort of testing does not occur, rather than extraordinary science which most nearly distinguishes science from other enterprises. If a demarcation criterion exists (we must not, I think, seek a sharp or decisive one), it may lie just in that part of science which Sir Karl ignores.
— Thomas S. Kuhn, "Logic of Discovery or Psychology of Research?", in Criticism and the Growth of Knowledge (1970), edited by Imre Lakatos and Alan Musgrave
Kuhn's view of demarcation is most clearly expressed in his comparison of astronomy with astrology. Since antiquity, astronomy has been a puzzle-solving activity and therefore a science. If an astronomer's prediction failed, then this was a puzzle that he could hope to solve for instance with more measurements or with adjustments of the theory. In contrast, the astrologer had no such puzzles since in that discipline "particular failures did not give rise to research puzzles, for no man, however skilled, could make use of them in a constructive attempt to revise the astrological tradition" ... Therefore, according to Kuhn, astrology has never been a science. [19]
Popper criticized Kuhn's demarcation criterion, saying that astrologers are engaged in puzzle solving, and that therefore Kuhn's criterion recognized astrology as a science. He stated that Kuhn's criterion results in a "major disaster ... [the] replacement of a rational criterion of science by a sociological one". [19]
Kuhn's work largely called into question Popper's demarcation, and emphasized the human, subjective quality of scientific change. Paul Feyerabend was concerned that the very question of demarcation was insidious: science itself had no need of a demarcation criterion, but instead some philosophers were seeking to justify a special position of authority from which science could dominate public discourse. [21] Feyerabend argued that science is not in fact special in terms of either its logic or method, and no claim to special authority made by scientists can be sustained. He argued that, within the history of scientific practice, no rule or method can be found that has not been violated or circumvented at some point in order to advance scientific knowledge. 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. According to Thagard's method, a theory is not scientific if it satisfies two conditions: [22]
Thagard specified that sometimes theories will spend some time as merely "unpromising" before they truly deserve the title of pseudoscience. He cited astrology as an example: it was stagnant compared to advances in physics during the 17th century, and only later became "pseudoscience" in the advent of alternative explanations provided by psychology during the 19th century.
Thagard also stated that his criteria should not be interpreted so narrowly as to allow willful ignorance of alternative explanations, or so broadly as to discount our modern science compared to science of the future. His definition is a practical one, which generally seeks to distinguish pseudoscience as areas of inquiry which are stagnant and without active scientific investigation.
Many historians of science are concerned with the development of science from its primitive origins; consequently they define science in sufficiently broad terms to include early forms of natural knowledge. In the article on science in the eleventh edition of the Encyclopædia Britannica, the scientist and historian William Cecil Dampier Whetham defined science as "ordered knowledge of natural phenomena and of the relations between them". [23] In his study of Greek science, Marshall Clagett defined science as "first, the orderly and systematic comprehension, description and/or explanation of natural phenomena and, secondly, the [mathematical and logical] tools necessary for the undertaking". [24] A similar definition appeared more recently in David Pingree's study of early science: "Science is a systematic explanation of perceived or imaginary phenomena, or else is based on such an explanation. Mathematics finds a place in science only as one of the symbolical languages in which scientific explanations may be expressed." [25] These definitions tend to emphasize the subject matter of science rather than its method and from these perspectives, the philosophical concern to establish a demarcation between science and non-science becomes "problematic, if not futile". [26]
Larry Laudan concluded, after examining various historical attempts to establish a demarcation criterion, that "philosophy has failed to deliver the goods" in its attempts to distinguish science from non-science—to distinguish science from pseudoscience. None of the past attempts would be accepted by a majority of philosophers nor, in his opinion, should they be accepted by them or by anyone else. He stated that many well-founded beliefs are not scientific and, conversely, many scientific conjectures are not well-founded. He also stated that demarcation criteria were historically used as machines de guerre in polemical disputes between "scientists" and "pseudo-scientists". Advancing a number of examples from everyday practice of football and carpentry and non-scientific scholarship such as literary criticism and philosophy, he considered the question of whether a belief is well-founded or not to be more practically and philosophically significant than whether it is scientific or not. In his judgment, the demarcation between science and non-science was a pseudo-problem that would best be replaced by examining the distinction between reliable and unreliable knowledge, without bothering to ask whether that knowledge is scientific or not. He would consign phrases like "pseudo-science" or "unscientific" to the rhetoric of politicians or sociologists. [2]
Others have disagreed with Laudan. Sebastian Lutz, for example, argued that demarcation does not have to be a single necessary and sufficient condition as Laudan implied. [2] Rather, Laudan's reasoning at most establishes that there has to be one necessary criterion and one possibly different sufficient criterion. [27]
Various typologies or taxonomies of sciences versus nonsciences, and reliable knowledge versus illusory knowledge, have been proposed. [28] Ian Hacking, Massimo Pigliucci, and others have noted that the sciences generally conform to Ludwig Wittgenstein's concept of family resemblances. [29] [30]
Other critics have argued for multiple demarcation criteria, [31] some suggesting that there should be one set of criteria for the natural sciences, another set of criteria for the social sciences, and claims involving the supernatural could have a set of pseudoscientific criteria. [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. And interpretations are always provisional, pending possible refutation by contradictory evidence ... Pseudoscience, by comparison, is scornful of evidence. The pseudoscientist reaches a preferred conclusion in advance, then selects evidence, often removed from any relevant context, to lend supposed support for their conclusions. Often the preconceived conclusion is one that justifies some closely held identity or ideology. Contradictory evidence is waved away or ignored, and as a last resort, one can always claim conspiracy to keep pseudoscientific ideas suppressed. [32]
Concerning science education, Michael D. Gordin wrote:
Every student in public or private schools takes several years of science, but only a small fraction of them pursue careers in the sciences. We teach the rest of them so much science so that they will appreciate what it means to be scientific – and, hopefully, become scientifically literate and apply some of those lessons in their lives. For such students, the myth of a bright line of demarcation is essential. [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 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. [35]
The demarcation problem has been compared to the problem of differentiating fake news from real news, which became prominent during the 2016 United States presidential election. [36]
Falsifiability is a deductive standard of evaluation of scientific theories and hypotheses, introduced by the philosopher of science Karl Popper in his book The Logic of Scientific Discovery (1934). A theory or hypothesis is falsifiable if it can be logically contradicted by an empirical test.
Sir Karl Raimund Popper was an Austrian–British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the classical inductivist views on the scientific method in favour of empirical falsification. According to Popper, a theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can be scrutinised with decisive experiments. Popper was opposed to the classical justificationist account of knowledge, which he replaced with critical rationalism, namely "the first non-justificational philosophy of criticism in the history of philosophy".
Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement whose central thesis is the verification principle. This theory of knowledge asserts that only statements verifiable through direct observation or logical proof are meaningful in terms of conveying truth value, information or factual content. Starting in the late 1920s, groups of philosophers, scientists, and mathematicians formed the Berlin Circle and the Vienna Circle, which, in these two cities, would propound the ideas of logical positivism.
Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claims; reliance on confirmation bias rather than rigorous attempts at refutation; lack of openness to evaluation by other experts; absence of systematic practices when developing hypotheses; and continued adherence long after the pseudoscientific hypotheses have been experimentally discredited. It is not the same as junk science.
Philosophy of science is the branch of philosophy concerned with the foundations, methods, and implications of science. Amongst its central questions are the difference between science and non-science, the reliability of scientific theories, and the ultimate purpose and meaning of science as a human endeavour. Philosophy of science focuses on metaphysical, epistemic and semantic aspects of scientific practice, and overlaps with metaphysics, ontology, logic, and epistemology, for example, when it explores the relationship between science and the concept of truth. Philosophy of science is both a theoretical and empirical discipline, relying on philosophical theorising as well as meta-studies of scientific practice. Ethical issues such as bioethics and scientific misconduct are often considered ethics or science studies rather than the philosophy of science.
Imre Lakatos was a Hungarian philosopher of mathematics and science, known for his thesis of the fallibility of mathematics and its "methodology of proofs and refutations" in its pre-axiomatic stages of development, and also for introducing the concept of the "research programme" in his methodology of scientific research programmes.
Paul Karl Feyerabend was an Austrian philosopher best known for his work in the philosophy of science. He started his academic career as lecturer in the philosophy of science at the University of Bristol (1955–1958); afterwards, he moved to the University of California, Berkeley, where he taught for three decades (1958–1989). At various points in his life, he held joint appointments at the University College London (1967–1970), the London School of Economics (1967), the FU Berlin (1968), Yale University (1969), the University of Auckland, the University of Sussex (1974), and, finally, the ETH Zurich (1980–1990). He gave lectures and lecture series at the University of Minnesota (1958–1962), Stanford University (1967), the University of Kassel (1977) and the University of Trento (1992).
The Vienna Circle of logical empiricism was a group of elite philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, chaired by Moritz Schlick. The Vienna Circle had a profound influence on 20th-century philosophy, especially philosophy of science and analytic philosophy.
The following outline is provided as an overview of and topical guide to the scientific method:
Commensurability is a concept in the philosophy of science whereby scientific theories are said to be "commensurable" if scientists can discuss the theories using a shared nomenclature that allows direct comparison of them to determine which one is more valid or useful. On the other hand, theories are incommensurable if they are embedded in starkly contrasting conceptual frameworks whose languages do not overlap sufficiently to permit scientists to directly compare the theories or to cite empirical evidence favoring one theory over the other. Discussed by Ludwik Fleck in the 1930s, and popularized by Thomas Kuhn in the 1960s, the problem of incommensurability results in scientists talking past each other, as it were, while comparison of theories is muddled by confusions about terms, contexts and consequences.
Originally, fallibilism is the philosophical principle that propositions can be accepted even though they cannot be conclusively proven or justified, or that neither knowledge nor belief is certain. The term was coined in the late nineteenth century by the American philosopher Charles Sanders Peirce, as a response to foundationalism. Theorists, following Austrian-British philosopher Karl Popper, may also refer to fallibilism as the notion that knowledge might turn out to be false. Furthermore, fallibilism is said to imply corrigibilism, the principle that propositions are open to revision. Fallibilism is often juxtaposed with infallibilism.
Verificationism, also known as the verification principle or the verifiability criterion of meaning, is a doctrine in philosophy which asserts that a statement is meaningful only if it is either empirically verifiable or a tautology. Verificationism rejects statements of metaphysics, theology, ethics and aesthetics as meaningless in conveying truth value or factual content, though they may be meaningful in influencing emotions or behavior.
Paul Richard Thagard is a Canadian philosopher who specializes in cognitive science, philosophy of mind, and the philosophy of science and medicine. Thagard is a professor emeritus of philosophy at the University of Waterloo. He is a writer, and has contributed to research in analogy and creativity, inference, cognition in the history of science, and the role of emotion in cognition.
Inductivism is the traditional and still commonplace philosophy of scientific method to develop scientific theories. Inductivism aims to neutrally observe a domain, infer laws from examined cases—hence, inductive reasoning—and thus objectively discover the sole naturally true theory of the observed.
Theory choice was a main problem in the philosophy of science in the early 20th century, and under the impact of the new and controversial theories of relativity and quantum physics, came to involve how scientists should choose between competing theories.
Laurens Lynn "Larry" Laudan was an American philosopher of science and epistemologist. He strongly criticized the traditions of positivism, realism, and relativism, and he defended a view of science as a privileged and progressive institution against popular challenges. Laudan's philosophical view of "research traditions" is seen as an important alternative to Imre Lakatos's "research programs".
Popper and After: Four Modern Irrationalists is a book about irrationalism by the philosopher David Stove. First published by Pergamon Press in 1982, it has since been reprinted as Anything Goes: Origins of the Cult of Scientific Irrationalism and Scientific Irrationalism: Origins of a Postmodern Cult.
An index list of articles about the philosophy of science.
Bold hypothesis or bold conjecture is a concept in the philosophy of science of Karl Popper, first explained in his debut The Logic of Scientific Discovery (1935) and subsequently elaborated in writings such as Conjectures and Refutations: The Growth of Scientific Knowledge (1963). The concept is nowadays widely used in the philosophy of science and in the philosophy of knowledge. It is also used in the social and behavioural sciences.
Astrology consists of a number of belief systems that hold that there is a relationship between astronomical phenomena and events or descriptions of personality in the human world. Astrology has been rejected by the scientific community as having no explanatory power for describing the universe. Scientific testing has found no evidence to support the premises or purported effects outlined in astrological traditions.
The demarcation problem may be formulated in the following terms: what distinguishes science from pseudoscience? This is an extreme way of putting it, since the more general problem, called the Generalized Demarcation Problem, is really the problem of the appraisal of scientific theories, and attempts to answer the question: when is one theory better than another?
Faced with ... competition from a variety of more or less exploitative rival healers, the doctors responsible for many or most of the Hippocratic treatises unite, at least, in their desire to turn the practice of healing into a τἐχνη. ... [N]ot only do they reject interference in most cases from priests and prophets, they also criticise many current practices and assumptions.