A statement, hypothesis, or theory has falsifiability (or is falsifiable) if it is contradicted by a basic statement, which, in an eventual successful or failed falsification, must respectively correspond to a true or hypothetical observation.For example, the claim "all swans are white and have always been white" is falsifiable since it is contradicted by this basic statement: "In 1697, during the Dutch explorer Willem de Vlamingh expedition, there were black swans on the shore of the Swan River in Australia", which in this case is a true observation. The concept is also known by the terms refutable and refutability.
The term proposition has a broad use in contemporary analytic philosophy. It is used to refer to some or all of the following: the primary bearers of truth-value, the objects of belief and other "propositional attitudes", the referents of that-clauses, and the meanings of declarative sentences. Propositions are the sharable objects of attitudes and the primary bearers of truth and falsity. This stipulation rules out certain candidates for propositions, including thought- and utterance-tokens which are not sharable, and concrete events or facts, which cannot be false.
A hypothesis is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used synonymously, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research, in a process beginning with an educated guess or thought.
A theory is a contemplative and rational type of abstract or generalizing thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking often is associated with such processes like observational study, research. Theories may either be scientific or other than scientific. Depending on the context, the results might, for example, include generalized explanations of how nature works. The word has its roots in ancient Greek, but in modern use it has taken on several related meanings.
The concept was introduced by the philosopher of science Karl Popper. He saw falsifiability as the logical part and the cornerstone of his scientific epistemology, which sets the limits of scientific inquiry. He proposed that statements and theories that are not falsifiable are unscientific. Declaring an unfalsifiable theory to be scientific would then be pseudoscience.
Philosophy of science is a sub-field of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultimate purpose of science. This discipline overlaps with metaphysics, ontology, and epistemology, for example, when it explores the relationship between science and truth.
Epistemology is the branch of philosophy concerned with the theory of knowledge.
The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what is observed, given that cognitive assumptions can distort how one interprets the observation. It involves formulating hypotheses, via induction, based on such observations; experimental and measurement-based testing of deductions drawn from the hypotheses; and refinement of the hypotheses based on the experimental findings. These are principles of the scientific method, as distinguished from a definitive series of steps applicable to all scientific enterprises.
The classical view of the philosophy of science is that it is the goal of science to prove hypotheses like "All swans are white" or to induce them from observational data. The Inductivist methodology supposes that one can somehow move from a series of statements such as 'here is a white swan', 'over there is a white swan', and so on, to a universal statement such as 'all swans are white'. As observed by David Hume, Immanuel Kant and later by Popper and others, this method is clearly deductively invalid, since it is always possible that there may be a non-white swan that has eluded observation(and, in fact, the discovery of the Australian black swan demonstrated the deductive invalidity of this particular statement). This is known as the problem of induction.
Inductive reasoning is a method of reasoning in which the premises are viewed as supplying some evidence for the truth of the conclusion; this is in contrast to deductive reasoning. While the conclusion of a deductive argument is certain, the truth of the conclusion of an inductive argument may be probable, based upon the evidence given. Many dictionaries define inductive reasoning as the derivation of general principles from specific observations, though there are many inductive arguments that do not have that form.
David Hume was a Scottish Enlightenment philosopher, historian, economist, and essayist, who is best known today for his highly influential system of philosophical empiricism, scepticism, and naturalism. Hume's empiricist approach to philosophy places him with John Locke, George Berkeley, Francis Bacon and Thomas Hobbes as a British Empiricist. Beginning with his A Treatise of Human Nature (1738), Hume strove to create a total naturalistic science of man that examined the psychological basis of human nature. Against philosophical rationalists, Hume held that passion rather than reason governs human behaviour. Hume argued against the existence of innate ideas, positing that all human knowledge is founded solely in experience.
Immanuel Kant was an influential German philosopher in the Age of Enlightenment. In his doctrine of transcendental idealism, he argued that space, time, and causation are mere sensibilities; "things-in-themselves" exist, but their nature is unknowable. In his view, the mind shapes and structures experience, with all human experience sharing certain structural features. He drew a parallel to the Copernican revolution in his proposition that worldly objects can be intuited a priori ('beforehand'), and that intuition is therefore independent from objective reality. Kant believed that reason is the source of morality, and that aesthetics arise from a faculty of disinterested judgment. Kant's views continue to have a major influence on contemporary philosophy, especially the fields of epistemology, ethics, political theory, and post-modern aesthetics.
One solution to the problem of induction, proposed by Immanuel Kant in Critique of Pure Reason, is to consider as valid, absolutely a priori, the conclusions that we would otherwise have drawn from these dubious inferential inductions. ( Popper 1959 , p. 6): "I do not think that his ingenious attempt to provide an a priori justification for synthetic statements was successful." However, if one finds one single swan that is not white, deductive logic admits the conclusion that the statement that all swans are white is false. Falsificationism thus strives for questioning, for falsification, of hypotheses instead of proving them or trying to view them as valid in any way.Following Kant, Popper accepted that we have to work with unproven hypotheses, but he refused that we have to justify them in any way and he wrote
The Critique of Pure Reason is a book by the German philosopher Immanuel Kant, in which the author seeks to determine the limits and scope of metaphysics. Also referred to as Kant's "First Critique", it was followed by the Critique of Practical Reason (1788) and the Critique of Judgment (1790). In the preface to the first edition, Kant explains that by a "critique of pure reason" he means a critique "of the faculty of reason in general, in respect of all knowledge after which it may strive independently of all experience" and that he aims to reach a decision about "the possibility or impossibility of metaphysics".
The Latin phrases a priori and a posteriori are philosophical terms popularized by Immanuel Kant's Critique of Pure Reason, one of the most influential works in the history of philosophy. However, in their Latin forms they appear in Latin translations of Euclid's Elements, of about 300 BC, a work widely considered during the early European modern period as the model for precise thinking.
For a statement to be questioned using observation, it needs to be at least theoretically possible that it can come into conflict with observation. A key observation of falsificationism is thus that a criterion of demarcation is needed to distinguish those statements that can come into conflict with observation and those that cannot, but the criterion itself concerns only the logical form of the theory:
I shall require that [the] logical form [of the theory] shall be such that it can be singled out, by means of empirical tests, in a negative sense: it must be possible for an empirical scientific system to be refuted by experience.— Karl Popper, Popper 1959. p 19
Popper always insisted on a clear distinction between the logic (of falsifiability) and its applied less precise methodology., The required logical form, the criterion, is that there must exist basic statements that contradict the theory (and also some that corroborate it because the theory must be consistent). This logical form informally implies the possibility of refutations by experience because, in its informal methodological context, a basic statement must be intersubjective and interpretable in terms of observations.
Objections can be raised against falsifiability as a criterion of demarcation similar to those which can be raised against verifiability. For example, as pointed out by manyand reformulated by Colin McGinn,
In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal methods of mathematics.
[w]e have to be able to infer that if a falsifying result has been found in a given experiment it will be found in future experiments; ... this is clearly an inductive inference.— Colin McGinn, McGinn 2002, sec. 3
Very early, in anticipation of this specific objection Popper wrote,
This attack would not disturb me. My proposal is based upon an asymmetry between verifiability and falsifiability; an asymmetry which results from the logical form of universal statements. For these are never derivable from singular statements, but can be contradicted by singular statements.— Karl Popper, Popper 1959. p 19
In its simple form, the point here is that although a singular existential statement such as 'there is a white swan in Europe' cannot be used to affirm a universal statement, it can be used to show that one is false: the statement 'there is a non white swan in Australia' implies that the universal statement 'all swans are white' is false. Moreover, this singular existential statement is empirical: it is impractical to observe all the swans in the world to verify that they are all white, but one can observe one swan that is not white. This shows the fundamental difference between verifiability and falsifiability. Also, in the logical form of the theory, there is no notion of future experiments, but only a (formal) class of basic statements that contradict it.
Such a simple contradiction with a basic statement is not what Popper calls a falsification.A falsification usually entails a derivation from a system of statements, which include the universal statement and initial conditions, to a singular statement, which is contradicted by a falsifying hypothesis, but the argument can be generalized. Popper explains
... it is possible by means of purely deductive inferences (with the help of the modus tollens of classical logic) to argue from the truth of singular statements to the falsity of universal statements. Such an argument to the falsity of universal statements is the only strictly deductive kind of inference that proceeds, as it were, in the ‘inductive direction’; that is, from singular to universal statements.— Karl Popper, Popper 1959, p. 19
Contemporary philosopher David Miller mentionsthat other similar objections have been anticipated and answered by Popper.
The falsifiability criterion does not imply that unfalsifiable systems such as logic, mathematics and metaphysics are not parts of science.Contrary to intuition, unfalsifiable statements can be embedded in—and deductively entailed by—falsifiable theories. For example, while "all men are mortal" is unfalsifiable, it is a logical consequence of the falsifiable theory that "all men die 150 years after their birth at the latest". Similarly, the ancient metaphysical and unfalsifiable idea of the existence of atoms has led to corresponding falsifiable modern theories. Popper invented the notion of metaphysical research programs to name such unfalsifiable ideas that guide the search for a new theory.
Thus falsificationism has two levels. At the logical level, scientists use deductive logic to attempt to falsify theories. At the non-logical level, they decide on some criteria, which use falsification and other factors, to pick which theories they will study, improve, replace, apply or (further) test. These other criteria may take into account a metaphysical research program. They are not considered in the formal falsifiability criterion, but they can give a meaning to this criterion. Needless to say, for Popper, these other criteria, the so-called rules of the game, are necessary. Some philosophers consider them as parts of Popper's demarcation criterion, but Popper viewed them only as a necessary context.
In contrast to Positivism, which held that statements are meaningless if they cannot be verified or falsified, Popper claimed that falsifiability is merely a special case of the more general notion of critical rationalism,even though he admitted that empirical refutation is one of the most effective methods by which theories can be criticized. Criticizability, in contrast to falsifiability, and thus rationality, may be comprehensive (i.e., have no logical limits), though this claim is controversial, even among proponents of Popper's philosophy and critical rationalism.
For Popper (and others) in any scientific discussion we accept a background knowledge.Such a background knowledge is thus implicit in the definition of falsifiability and corresponds to different types of statements, their relationship and their interpretation in terms of observations and measurements.
Recall that a theory is falsifiable if it is contradicted by a basic statement. It remains to define what kind of statements create theories and what are basic statements. Scientific theories are a particular kind of universal statements.Basic statements are particular kind of existential statements. Not all universal statements are theories and not all existential statements are basic statements. Theories have the form of strictly universal statements. Basic statements have the form of singular existential statements. Thus we need to distinguish between existential and universal statements and also between singular and strict statements.
Existential and universal statements are built-in concepts in logic. The first are statements such as "there is a white swan". Logicians call these statements existential statements, since they assert the existence of something. They are equivalent to a first-order logic statement of the form: There exists an x such that x is a swan, and x is white. The second are statements that categorize all instances of something, such as "all swans are white". Logicians call these statements universal. They are usually parsed in the form: For all x, if x is a swan, then x is white.
Unlike existential and universal statements, singular and strict statements are not built-in concepts in logic, because they correspond to a specific perspective on our experience of the world.We can understand them in terms of the concepts of universal or individual names:
... ‘dictator’, ‘planet’, ‘H2O’ are universal concepts or universal names. ‘Napoleon’, ‘the earth’, ‘the Atlantic’ are singular or individual concepts or names. In these examples individual concepts or names appear to be characterized either by being proper names, or by having to be defined by means of proper names, whilst universal concepts or names can be defined without the use of proper names.— Karl Popper, Popper 1959, pp. 42–43
A statement is strict or pure, if it does not use any individual name. So, a law of nature cannot refer to particular things. The sentence "This apple is attracted by the planet earth" is not a scientific statement. Popper wrote an entire section on strictly universal and strictly existential statements,because he considers the distinction between universal and individual concepts or names to be of fundamental importance.
A statement is singular if it contains an individual name or the equivalent.So, a basic statement must make reference to a specific thing or specific location and time. The sentence "There exists a black swan" is not a basic statement, but the statement "There is a black swan on the shore of the Swan River" is a basic statement, it is a singular existential statement.
Popper arrived at these conditions through an analysis of what one expects from basic statements.In addition, a basic statement must be inter-subjective. So, "John saw a black swan on the shore of the Swan River" is not a basic statement.
Falsifiability is defined strictly in terms of the logical form of the theory,but this criterion of demarcation can not work without being complemented by methodological rules. Thus, contemporary philosophers consider that Popper's demarcation criterion has two parts: the logical part (stated in terms of rules of inference - ways to logically infer new statements from existing statements) and the methodological part (stated in terms of rules that do not claim to prove anything). The methodological rules define falsification. They should not be confused with the (logical) rules of inferences used to define falsifiability, which is about the logical form of the theory.
In this larger picture, the fact that a single basic statement can contradict a strictly universal statement, though true logically, is in itself useless, because it cannot lead to a falsification. To support falsification, Popper requires that a class of basic statements corroborate a falsifying hypothesis.A basic statement corroborates the falsifying hypothesis, if it does not logically contradict it, but contradicts the theory to be falsified. Though it corresponds to the empirical notion of reproducible experiments, this requirement exists entirely at the formal level and must be complemented by methodological rules in a falsification process.
Naïve falsificationism is an unsuccessful attempt to prescribe a rationally unavoidable method for science. Sophisticated methodological falsification, on the other hand, is a prescription of a way in which scientists ought to behave as a matter of choice. The object of this is to arrive at an incremental process whereby theories become less bad.[ citation needed ]
Naïve falsification considers scientific statements individually. Scientific theories are formed from groups of these sorts of statements, and it is these groups that must be accepted or rejected by scientists. Scientific theories can always be defended by the addition of ad hoc hypotheses.[ citation needed ] As Popper put it, a decision is required on the part of the scientist to accept or reject the statements that go to make up a theory or that might falsify it. At some point, the weight of the ad hoc hypotheses and disregarded falsifying observations will become so great that it becomes unreasonable to support the base theory any longer, and a decision will be made to reject it.[ citation needed ]
Although the logic of naïve falsification is valid, it is rather limited. Nearly any statement can be made to fit the data, so long as one makes the requisite 'compensatory adjustments'. Popper drew attention to these limitations in The Logic of Scientific Discovery in response to criticism from Pierre Duhem. W. V. Quine expounded this argument in detail, calling it confirmation holism. To logically falsify a universal, one must find a true falsifying singular statement. But Popper pointed out that it is always possible to change the universal statement or the existential statement so that falsification does not occur.On hearing that a black swan has been observed in Australia, one might introduce the ad hoc hypothesis, 'all swans are white except those found in Australia'; or one might adopt another, more cynical view about some observers, 'Australian bird watchers are incompetent'.
Thus, naïve falsification ought to, but does not, supply a way of handling competing hypotheses for many subject controversies (for instance conspiracy theories and urban legends). People arguing that there is no support for such an observation may argue that there is nothing to see, that all is normal, or that the differences or appearances are too small to be statistically significant. On the other side are those who concede that an observation has occurred and that a universal statement has been falsified as a consequence. Therefore, naïve falsification does not enable scientists, who rely on objective criteria, to present a definitive falsification of universal statements.[ citation needed ]
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In place of naïve falsification, Popper envisioned science as progressing by the successive rejection of falsified theories, rather than falsified statements. Falsified theories are to be replaced by theories that can account for the phenomena that falsified the prior theory, that is, with greater explanatory power. For example, Aristotelian mechanics explained observations of everyday situations, but were falsified by Galileo's experiments, and were replaced by Newtonian mechanics, which accounted for the phenomena noted by Galileo (and others). Newtonian mechanics' reach included the observed motion of the planets and the mechanics of gases. The Youngian wave theory of light (i.e., waves carried by the luminiferous aether) replaced Newton's (and many of the Classical Greeks') particles of light but in turn was falsified by the Michelson-Morley experiment and was superseded by Maxwell's electrodynamics and Einstein's special relativity, which did account for the newly observed phenomena. Furthermore, Newtonian mechanics applied to the atomic scale was replaced with quantum mechanics, when the old theory could not provide an answer to the ultraviolet catastrophe, the Gibbs paradox, or how electron orbits could exist without the particles radiating away their energy and spiraling towards the centre. Thus the new theory had to posit the existence of unintuitive concepts such as energy levels, quanta and Heisenberg's uncertainty principle.
At each stage, experimental observation made a theory untenable (i.e., falsified it) and a new theory was found that had greater explanatory power (i.e., could account for the previously unexplained phenomena), and as a result, provided greater opportunity for its own falsification.
Popper uses falsification as a criterion of demarcation to draw a sharp line between those theories that are scientific and those that are unscientific. It is useful to know if a statement or theory is falsifiable, if for no other reason than that it provides us with an understanding of the ways in which one might assess the theory. One might at the least be saved from attempting to falsify a non-falsifiable theory, or come to see an unfalsifiable theory as unsupportable. Popper claimed that, if a theory is falsifiable, then it is scientific.
The Popperian criterion excludes from the domain of science not unfalsifiable statements but only whole theories that contain no falsifiable statements; thus it leaves us with the Duhemian problem of what constitutes a 'whole theory' as well as the problem of what makes a statement 'meaningful'. Popper's own falsificationism, thus, is not only an alternative to verificationism, it is also an acknowledgement of the conceptual distinction that previous theories had ignored.
In the philosophy of science, verificationism (also known as the verifiability theory of meaning) holds that a statement must, in principle, be empirically verifiable in order that it be both meaningful and scientific. This was an essential feature of the logical positivism of the so-called Vienna Circle that included such philosophers as Moritz Schlick, Rudolf Carnap, Otto Neurath, the Berlin philosopher Hans Reichenbach, and the logical empiricism of A.J. Ayer. Popper noticed that the philosophers of the Vienna Circle had mixed two different problems, that of meaning and that of demarcation, and had proposed in verificationism a single solution to both. In opposition to this view, Popper emphasized that there are meaningful theories that are not scientific, and that, accordingly, a criterion of meaningfulness does not coincide with a criterion of demarcation.
Thus, Popper urged that verifiability be replaced with falsifiability as the criterion of demarcation. On the other hand, he strictly opposed the view that non-falsifiable statements are meaningless or otherwise inherently bad, and noted that falsificationism is only concerned with meaningful statements.
Falsifiability has been used in the McLean v. Arkansas case (in 1982), the Daubert case (in 1993) and other cases (see below). A survey of 303 federal judgesconducted in 1998 (and fully reported in Krafka 2002) revealed that "[P]roblems with the nonfalsifiable nature of an expert’s underlying theory and difficulties with an unknown or too-large error rate were cited in less than 2% of cases."
In the ruling of the McLean v. Arkansas case, Judge William Overton used falsifiability as one of the criteria to determine that "creation science" was not scientific and should not be taught in Arkansas public schools as such (it can be taught as religion). In his testimony, philosopher Michael Ruse defined the characteristics which constitute science as (see Pennock 2000 , p. 5 and Ruse 2010):
In his conclusion related to this criterion Judge Overton stated that
While anybody is free to approach a scientific inquiry in any fashion they choose, they cannot properly describe the methodology as scientific, if they start with the conclusion and refuse to change it regardless of the evidence developed during the course of the investigation.— William Overton, McLean v. Arkansas 1982, at the end of section IV. (C)
In the Daubert case, the majority opinion proposed the so-called five Daubert factors, which include falsifiability, to define a scientific methodology that is acceptable in courts of law.These original Daubert factors have been cited in the Kumho Tire Co. v. Carmichael case and in the U.S. v. PRIME case (United States v. Prime 2002). In the Daubert case, Associate Justice Harry Blackmun, delivering the majority opinion of the United States Supreme Court, has cited Popper and other philosophers of science:
Ordinarily, a key question to be answered in determining whether a theory or technique is scientific knowledge that will assist the trier of fact will be whether it can be (and has been) tested. Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry. Green 645. See also C. Hempel, Philosophy of Natural Science 49 (1966) ([T]he statements constituting a scientific explanation must be capable of empirical test); K. Popper, Conjectures and Refutations: The Growth of Scientific Knowledge 37 (5th ed. 1989) ([T]he criterion of the scientific status of a theory is its falsifiability, or refutability, or testability) (emphasis deleted).— Harry Blackmun, Daubert v. Merrell Dow Pharmaceuticals, Inc. 1993, p. 593
In a partially dissident opinion, Chief Justice William Rehnquist supported by Associate Justice John Paul Stevens, responded that:
I defer to no one in my confidence in federal judges; but I am at a loss to know what is meant when it is said that the scientific status of a theory depends on its falsifiability, and I suspect some of them will be, too.— William Rehnquist, Daubert v. Merrell Dow Pharmaceuticals, Inc. 1993, p. 600
Professor of Law David H. Kayeargued that references to the Daubert majority opinion confused falsifiability and falsification and that "inquiring into the existence of meaningful attempts at falsification is an appropriate and crucial consideration in admissibility determinations."
There are combinations of prediction types and methodologies that, while each component is compatible with falsifiability on its own, renders falsification impossible together.
One example is the combination of statistical predictions in which individual exceptions do not falsify the theory, with different evidence standards for different data points in which one type of data point only require ordinary evidence while another require extraordinary evidence.
On one hand, the theory that there are no black swans is falsifiable even if there is a requirement of extraordinary evidence for a black swan, since it is not impossible for an individual observation of a black swan to eventually meet the requirement of extraordinary evidence. On the other hand, in a country where there are, in reality, the same number of black swans as white swans, the theory that there are more white swans than black swans at a population level with individual exceptions is falsifiable - as long as the level of evidence required to record a white swan is the same as that for recording black swans. But if the theory is that white swans are more statistically common than black swans with exceptions and a higher level of evidence is required for recording a black swan than for recording a white swan, the difference in evidence standards will cause more white swans than black swans to be recorded even in a country where the ratio is in fact 50/50. This makes the combination of statistical prediction with exceptions and differences in evidence standards incompatible with falsifiability.
This has been implicated in the replication crisis, especially in psychology in which the two methodologies are more common than in other fields and therefore more often combine to prevent falsifiability even though the two factors are not unheard of on their own in other fields. The problem of falsifiability can also be caused by the active application of methodologies, and therefore spreading issues to other fields that psychology interacts with through interdisciplines, such as evolutionary psychology spreading the problems to evolution research. One solution is to allow other fields to help falsifiability in psychology, as would have been possible had the problem been a passive lack of components for falsifiability.
Several contemporary philosophers of science and analytic philosophers are strongly critical of Popper's philosophy of science. [ better source needed ] Popper's mistrust of inductive reasoning has led to claims that he misrepresents scientific practice.
Sir Karl Popper is not really a participant in the contemporary professional philosophical dialogue; quite the contrary, he has ruined that dialogue. If he is on the right track, then the majority of professional philosophers the world over have wasted or are wasting their intellectual careers. The gulf between Popper's way of doing philosophy and that of the bulk of contemporary professional philosophers is as great as that between astronomy and astrology."— W. W. Bartley III, "III: Biology – evolutionary epistemology", 1976
Popper's ideas have failed to convince the majority of professional philosophers because his theory of conjectural knowledge does not even pretend to provide positively justified foundations of belief. Nobody else does better, but they keep trying, like chemists still in search of the Philosopher's Stone or physicists trying to build perpetual motion machines.— Rafe Champion, "Agreeing to Disagree: Bartley's Critique of Reason", 1985
Whereas Popper was concerned in the main with the logic of science, Thomas Kuhn's influential book The Structure of Scientific Revolutions examined in detail the history of science. Kuhn argued that scientists work within a conceptual paradigm that strongly influences the way in which they see data. Scientists will go to great length to defend their paradigm against falsification, by the addition of ad hoc hypotheses to existing theories. Changing a 'paradigm' is difficult, as it requires an individual scientist to break with his or her peers and defend a heterodox theory.
Some falsificationists saw Kuhn's work as a vindication, since it provided historical evidence that science progressed by rejecting inadequate theories, and that it is the decision, on the part of the scientist, to accept or reject a theory that is the crucial element of falsificationism. Foremost amongst these was Imre Lakatos.
Lakatos attempted to explain Kuhn's work by arguing that science progresses by the falsification of research programs rather than the more specific universal statements of naïve falsification. In Lakatos' approach, a scientist works within a research program that corresponds roughly with Kuhn's 'paradigm'. Whereas Popper rejected the use of ad hoc hypotheses as unscientific, Lakatos accepted their place in the development of new theories.
Paul Feyerabend examined the history of science with a more critical eye, and ultimately rejected any prescriptive methodology at all. He rejected Lakatos' argument for ad hoc hypothesis, arguing that science would not have progressed without making use of any and all available methods to support new theories. He rejected any reliance on a scientific method, along with any special authority for science that might derive from such a method. Rather, he claimed that if one is keen to have a universally valid methodological rule, epistemological anarchism or anything goes would be the only candidate. For Feyerabend, any special status that science might have derives from the social and physical value of the results of science rather than its method.[ citation needed ]
In their book Fashionable Nonsense (published in the UK as Intellectual Impostures) the physicists Alan Sokal and Jean Bricmont criticized falsifiability on the grounds that it does not accurately describe the way science really works. They argue that theories are used because of their successes, not because of the failures of other theories. Their discussion of Popper, falsifiability and the philosophy of science comes in a chapter entitled "Intermezzo," which contains an attempt to make clear their own views of what constitutes truth, in contrast with the extreme epistemological relativism of postmodernism.
Sokal and Bricmont write, "When a theory successfully withstands an attempt at falsification, a scientist will, quite naturally, consider the theory to be partially confirmed and will accord it a greater likelihood or a higher subjective probability. ... But Popper will have none of this: throughout his life he was a stubborn opponent of any idea of 'confirmation' of a theory, or even of its 'probability'. ... [but] the history of science teaches us that scientific theories come to be accepted above all because of their successes." (Sokal and Bricmont 1997, 62f)
They further argue that falsifiability cannot distinguish between astrology and astronomy, as both make technical predictions that are sometimes incorrect.
David Miller, a contemporary philosopher of critical rationalism, has attempted to defend Popper against these claims.Miller argues that astrology does not lay itself open to falsification, while astronomy does, and this is the litmus test for science.
Karl Popper argued that Marxism shifted from falsifiable to unfalsifiable.
Some economists, such as those of the Austrian School, believe that macroeconomics is empirically unfalsifiable and that thus the only appropriate means to understand economic events is by logically studying the intentions of individual economic decision-makers, based on certain fundamental truths.Prominent figures within the Austrian School of economics, Ludwig von Mises and Friedrich Hayek were associates of Karl Popper's, with whom they co-founded the Mont Pelerin Society.
Numerous examples of potential (indirect) ways to falsify common descent have been proposed by its proponents. J.B.S. Haldane, when asked what hypothetical evidence could disprove evolution, replied "fossil rabbits in the Precambrian era".Richard Dawkins adds that any other modern animal, such as a hippo, would suffice. Karl Popper at first spoke against the testability of natural selection but recanted, "I have changed my mind about the testability and logical status of the theory of natural selection, and I am glad to have the opportunity to make a recantation."
Much of the criticism against young-Earth creationism is based on evidence in nature that the Earth is much older than adherents believe. Confronting such evidence, some adherents make an argument (called the Omphalos hypothesis) that the world was created with the appearance of age; e.g., the sudden appearance of a mature chicken capable of laying eggs. This hypothesis is non-falsifiable since no evidence about the age of the earth (or any astronomical feature) can be shown not to be fabricated during creation.
Theories of history or politics that allegedly predict future events have a logical form that renders them neither falsifiable nor verifiable. They claim that for every historically significant event, there exists an historical or economic law that determines the way in which events proceeded. Failure to identify the law does not mean that it does not exist, yet an event that satisfies the law does not prove the general case. Evaluation of such claims is at best difficult. On this basis, Popper "fundamentally criticized historicism in the sense of any preordained prediction of history"and argued that neither Marxism nor psychoanalysis was science, although both made such claims. Again, this does not mean that any of these types of theories is necessarily incorrect. Popper considered falsifiability a test of whether theories are scientific, not of whether propositions that they contain or support are true.
Like all formal sciences, mathematics is not concerned with the validity of theories based on observations in the empirical world, but rather, mathematics is occupied with the theoretical, abstract study of such topics as quantity, structure, space and change. Methods of the mathematical sciences are, however, applied in constructing and testing scientific models dealing with observable reality. Albert Einstein wrote, "One reason why mathematics enjoys special esteem, above all other sciences, is that its laws are absolutely certain and indisputable, while those of other sciences are to some extent debatable and in constant danger of being overthrown by newly discovered facts."
... the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability.— Popper
Philosophers' talk about rationality is apt to soar into the stratosphere of abstractions so it must be stated that Bartley's approach has immediate and practical applications. Following his teacher, Karl Popper, the operating principle of Bartley's rationalism is the formula 'I may he wrong and you may be right, and by means of critical discussion we may get nearer to the truth of the matter'. This simple principle of rationality requires philosophical defence in depth, backed up by a wide range of improved traditions and institutions to sustain the flow of ideas and critical discussion. These vehicles already exist of course, if only in rudimentary forms, among them talk-back radio, the range of serious 'little magazines' and programs on TV which allow opposing points of view to be explored and debated. These forums are vitally important despite all their imperfections and lapses into the trivial and the banal; the important thing is that they exist, not that they should be scrupulously fair and unbiased at all times nor that they confine themselves to matters of great moral and intellectual moment. Bartley has provided philosophical air support for the footsoldiers of rationality. He offers a solution to the basic logical problem of rationality, namely how can we justify the basic premise of rationality, that is, the principle of rationality itself, the principle that we should engage in critical discussion to seek for rationally defensible beliefs?
Sir Karl Raimund Popper was an Austrian-born British philosopher and professor.
Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, was a movement in Western philosophy whose central thesis was the verification principle. Also called verificationism, this would-be theory of knowledge asserted that only statements verifiable through direct observation or logical proof are meaningful. 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 are claimed 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; and absence of systematic practices when developing theories, and continued adherence long after they have been experimentally discredited. The term pseudoscience is considered pejorative because it suggests something is being presented as science inaccurately or even deceptively. Those described as practicing or advocating pseudoscience often dispute the characterization.
Occam's razor is the problem-solving principle that states "Entities should not be multiplied without necessity." The idea is attributed to English Franciscan friar William of Ockham, a scholastic philosopher and theologian. It is sometimes misquoted in pop culture and other media by some form of the statement "The simplest solution is most likely the right one." Occam's razor instead says that when presented with competing hypotheses that make the same predictions, one should select the solution with the fewest assumptions, and it is not meant to be a way of choosing between hypotheses that make different predictions.
The Logic of Scientific Discovery is a 1959 book about the philosophy of science by Karl Popper. Popper rewrote his book in English from the 1934 German original, titled Logik der Forschung. Zur Erkenntnistheorie der modernen Naturwissenschaft, which literally translates as, "Logic of Research: On the Epistemology of Modern Natural Science"'.
A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results. Where possible, theories are tested under controlled conditions in an experiment. In circumstances not amenable to experimental testing, theories are evaluated through principles of abductive reasoning. Established scientific theories have withstood rigorous scrutiny and embody scientific knowledge.
Scientific evidence is evidence which serves to either support or counter a scientific theory or hypothesis. Such evidence is expected to be empirical evidence and interpretation in accordance with scientific method. Standards for scientific evidence vary according to the field of inquiry, but the strength of scientific evidence is generally based on the results of statistical analysis and the strength of scientific controls.
The following outline is provided as an overview of and topical guide to scientific method:
The hypothetico-deductive model or method is a proposed description of scientific method. According to it, scientific inquiry proceeds by formulating a hypothesis in a form that can be falsifiable, using a test on observable data where the outcome is not yet known. A test outcome that could have and does run contrary to predictions of the hypothesis is taken as a falsification of the hypothesis. A test outcome that could have, but does not run contrary to the hypothesis corroborates the theory. It is then proposed to compare the explanatory value of competing hypotheses by testing how stringently they are corroborated by their predictions.
Critical rationalism is an epistemological philosophy advanced by Karl Popper. Popper wrote about critical rationalism in his works: The Logic of Scientific Discovery, The Open Society and its Enemies, Conjectures and Refutations, The Myth of the Framework, and Unended Quest. Ernest Gellner is another notable proponent of this approach.
The demarcation problem in the philosophy of science and epistemology is about how to distinguish between science and non-science, including between science, pseudoscience, and other products of human activity, like art and literature, and beliefs. The debate continues after over two millennia of dialogue among philosophers of science and scientists in various fields, and despite a broad agreement on the basics of the scientific method.
In philosophy and models of scientific inquiry, postpositivism is a metatheoretical stance that critiques and amends positivism. While positivists emphasize independence between the researcher and the researched person, postpositivists argue that theories, background, knowledge and values of the researcher can influence what is observed. Postpositivists pursue objectivity by recognizing the possible effects of biases. While positivists emphasize quantitative methods, postpositivists consider both quantitative and qualitative methods to be valid approaches.
Testability, a property applying to an empirical hypothesis, involves two components:
Verificationism, also known as the verification principle or the verifiability criterion of meaning, is the philosophical doctrine that only statements that are empirically verifiable are cognitively meaningful, or else they are truths of logic (tautologies).
In the philosophy of science, models of scientific inquiry have two functions: first, to provide a descriptive account of how scientific inquiry is carried out in practice, and second, to provide an explanatory account of why scientific inquiry succeeds as well as it appears to do in arriving at genuine knowledge.
The search for scientific knowledge ends far back into antiquity. At some point in the past, at least by the time of Aristotle, philosophers recognized that a fundamental distinction should be drawn between two kinds of scientific knowledge—roughly, knowledge that and knowledge why. It is one thing to know that each planet periodically reverses the direction of its motion with respect to the background of fixed stars; it is quite a different matter to know why. Knowledge of the former type is descriptive; knowledge of the latter type is explanatory. It is explanatory knowledge that provides scientific understanding of the world.
Inductivism is the traditional model of scientific method attributed to Francis Bacon, who in 1620 vowed to subvert allegedly traditional thinking. In the Baconian model, one observes nature, proposes a modest law to generalize an observed pattern, confirms it by many observations, ventures a modestly broader law, and confirms that, too, by many more observations, while discarding disconfirmed laws. The laws grow ever broader but never much exceed careful, extensive observation. Thus, freed from preconceptions, scientists gradually uncover nature's causal and material structure.
Explanatory power is the ability of a hypothesis or theory to effectively explain the subject matter it pertains to. The opposite of explanatory power is explanatory impotence.
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.
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