Popper's Falsifiability

Space, Space Programs, Manned and Unmanned Missions
Flattop
Joined: 17 Nov 2008, 18:31

23 Apr 2017, 23:01 #1

Falsifiability or refutability of a statement, hypothesis, or theory is the inherent possibility that it can be proven false. A statement is called falsifiable if it is possible to conceive of an observation or an argument which negates the statement in question. In this sense, falsify is synonymous with nullify, meaning to invalidate or "shown to be false".
For example, by the problem of induction, no number of confirming observations can verify a universal generalization, such as All swans are white, since it is logically possible to falsify it by observing a single black swan. Thus, the term falsifiability is sometimes synonymous to testability. Some statements, such as It will be raining here in one million years, are falsifiable in principle, but not in practice.
The concern with falsifiability gained attention by way of philosopher of science Karl Popper's scientific epistemology "falsificationism". Popper stresses the problem of demarcation—distinguishing the scientific from the unscientific—and makes falsifiability the demarcation criterion, such that what is unfalsifiable is classified as unscientific, and the practice of declaring an unfalsifiable theory to be scientifically true is pseudoscience.
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. Popper argued that this would require the inference of a general rule from a number of individual cases, which is inadmissible in deductive logic. 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.
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 (Chorlton, 2012). Popper chose falsifiability as the name of this criterion.
"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, The Logic of Scientific Discovery,
Popper stressed that unfalsifiable statements are important in 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 "every man dies before he reaches the age of 150 years". 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.  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 criticizability, 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.
In work beginning in the 1930s, Popper gave falsifiability a renewed emphasis as a criterion of empirical statements in science.
Popper noticed that two types of statements are of particular value to scientists.
The first are statements of observations, such as "there is a white swan". Logicians call these statements singular existential statements, since they assert the existence of some particular thing. They are equivalent to a predicate calculus 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. Scientific laws are commonly supposed to be of this type. One difficult question in the methodology of science is: How does one move from observations to laws? How can one validly infer a universal statement from any number of existential statements?
Inductivist methodology supposed that one can somehow move from a series of singular existential statements to a universal statement. That is, that one can move from 'this is a white swan', 'that is a white swan', and so on, to a universal statement such as 'all swans are white'. 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).
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.
https://en.wikipedia.org/wiki/Falsifiability
"It'd be nice to please everyone but I thought it would be more interesting to have a point of view."
-- Oscar Levant
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Flattop
Joined: 17 Nov 2008, 18:31

23 Apr 2017, 23:10 #2

Many contemporary philosophers of science and analytic philosophers are strongly critical of Popper's philosophy of science.  Popper's mistrust of inductive reasoning has led to claims that he misrepresents scientific practice.
Bartley in 1978 claimed:
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 in Philosophia
Rafe Champion said:
"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"
David Miller said:
What distinguishes science from all other human endeavours is that the accounts of the world that our best, mature sciences deliver are strongly supported by evidence and this evidence gives us the strongest reason to believe them.' That anyway is what is said at the beginning of the advertisement for a recent conference on induction at a celebrated seat of learning in the UK. It shows how much critical rationalists still have to do to make known the message of Logik der Forschung concerning what empirical evidence is able to do and what it does."  -- David Miller "Some hard questions for critical rationalism"
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.
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.
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.
Many philosophers believe that mathematics is not experimentally falsifiable, and thus not a science according to the definition of Karl Popper. However, in the 1930s Gödel's incompleteness theorems proved that there does not exist a set of axioms for mathematics which is both complete and consistent. Karl Popper concluded that "most mathematical theories are, like those of physics and biology, hypothetico-deductive: pure mathematics therefore turns out to be much closer to the natural sciences whose hypotheses are conjectures, than it seemed even recently." Other thinkers, notably Imre Lakatos, have applied a version of falsificationism to mathematics itself.
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."
https://en.wikipedia.org/wiki/Falsifiability
"It'd be nice to please everyone but I thought it would be more interesting to have a point of view."
-- Oscar Levant
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blackirishkarma
Joined: 09 Aug 2013, 03:20

24 Apr 2017, 18:15 #3

Interesting discussion. If you really want to understand Popper's theory of falsification you should read his book "The Logic of Scientific Discovery". Quite obviously, at least some of the critics of his theory in this discussion have not read the book or they wouldn't be making the arguments that they are. At any rate, in its simplest form I have found Popper's theory of falsification to be an accurate way of distinguishing between what is science and what is not. Obviously.... there are those who would disagree strenously as there are a lot of fields of study that I can think of that claim to be science but are not falsifiable. 
The increase of misery in the present state of society is parallel and equal to the increase of wealth..... Unknown member of Parliament 1840's
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blackirishkarma
Joined: 09 Aug 2013, 03:20

24 Apr 2017, 18:20 #4

Also... not to quibble but why is this in "The Cape" category?

Perhaps we should start a special category.... "The Rabbit Hole" or.... "Things I disagree with blackirish about". 

Oh... never mind we already Image seem to have that category all across the group.
The increase of misery in the present state of society is parallel and equal to the increase of wealth..... Unknown member of Parliament 1840's
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Flattop
Joined: 17 Nov 2008, 18:31

24 Apr 2017, 23:51 #5

This is the closest thing we have to a science category, and I am not sure I am interested enough to create an actual science category.
"It'd be nice to please everyone but I thought it would be more interesting to have a point of view."
-- Oscar Levant
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Flattop
Joined: 17 Nov 2008, 18:31

25 Apr 2017, 00:18 #6

"We passed a very pleasant evening, though I made the slight mistake of taking Poirot to a crook play.  There is one piece of advice I offer to all my readers.  Never take a soldier to a military play, a sailor to a naval play, a Scotsman to a Scottish play, a detective to a thriller -- and an actor to any play whatsoever!  The shower of destructive criticism in each case is somewhat devastating.  Poirot never ceased to complain of faulty psychology, and the hero detective's lack of order and method nearly drove him demented.  We parted that night with Poirot still explaining how the whole business might have been laid bare in the first half of the first act.
"'But in that case, Poirot, there would have been no play,' I pointed out.
"Poirot was forced to admit that perhaps that was so."
-- Captain Arthur Hatings in his first person narration of Agatha Christie's novel Poirot Loses A Client
"It'd be nice to please everyone but I thought it would be more interesting to have a point of view."
-- Oscar Levant
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blackirishkarma
Joined: 09 Aug 2013, 03:20

25 Apr 2017, 00:41 #7

My wife said much the same thing when we went to see the movie "Gravity". The scene where the main character has his momentum arrested but then somehow keeps drifting uncontrollably away was almost more than I could stand even though I enjoyed the movie for the most part. 
The increase of misery in the present state of society is parallel and equal to the increase of wealth..... Unknown member of Parliament 1840's
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