Science: Conjectures and Refutations

[bboyer]

Science: Conjectures and Refutations
Sir Karl Popper

Mr. Turnbull had predicted evil consequences . . . and was now doing the best in his power to bring about the verification of his own prophecies.
ANTHONY TROLLOPE

When I received the list of participants in this course and realized that I had been asked to speak to philosophical colleagues I thought, after some hesitation and consultation, that you would probably prefer me to speak about those problems which interest me most, and about those developments with which I am most intimately acquainted. I therefore decided to do what I have never done before: to give you a report on my own work in the philosophy of science, since the autumn of 1919 when I first began to grapple with the problem, "When should a theory be ranked as scientific?" or "Is there a criterion for the scientific character or status of a theory?"

The problem which troubled me at the time was neither, "When is a theory true?" nor, "When is a theory acceptable?" My problem was different. I wished to distinguish between science and pseudo-science; knowing very well that science often errs, and that pseudo-science may happen to stumble on the truth.

I knew, of course, the most widely accepted answer to my problem: that science is distinguished from pseudo-science or from "metaphysics" by its empirical method, which is essentially inductive, proceeding from observation or experiment. But this did not satisfy me. On the contrary, I often formulated my problem as one of distinguishing between a genuinely empirical method and a non-empirical or even a pseudo-empirica1 method - that is to say, a method which, although it appeals to observation and experiment, nevertheless does not come up to scientific standards. The latter method may be exemplified by astrology with its stupendous mass of empirical evidence based on observation - on horoscopes and on biographies.

But as it was not the example of astrology which led me to my problem I should perhaps briefly describe the atmosphere in which my problem arose and the examples by which it was stimulated. After the collapse of the Austrian Empire there had been a revolution in Austria: the air was full of revolutionary slogans and ideas, and new and often wild theories. Among the theories which interested me Einstein's theory of relativity was no doubt by far the most important. Three others were Marx's theory of history, Freud's psycho-analysis, and Alfred Adler's so-called "individual psychology."

There was a lot of popular nonsense talked about these theories, and especially about relativity (as still happens even today), but I was fortunate in those who introduced me to the study of this theory. We all - the small circle of students to which I belonged - were thrilled with the result of Eddington's eclipse observations which in 1919 brought the first important confirmation of Einstein's theory of gravitation. It was a great experience for us, and one which had a lasting influence on my intellectual development.

The three other theories I have mentioned were also widely discussed among students at that time. I myself happened to come into personal contact with Alfred Adler, and even to co-operate with him in his social work among the children and young people in the working-class districts of Vienna where he had established social guidance clinics.

It was during the summer of 1919 that I began to feel more and more dissatisfied with these three theories - the Marxist theory of history, psychoanalysis, and individual psychology; and I began to feel dubious about their claims to scientific status. My problem perhaps first took the simple form, "What is wrong with Marxism, psycho-analysis, and individual psychology? Why are they so different from physical theories, from Newton's theory, and especially from the theory of relativity?"

To make this contrast clear I should explain that few of us at the time would have said that we believed in the truth of Einstein's theory of gravitation. This shows that it was not my doubting the truth of those other three theories which bothered me, but something else. Yet neither was it that I merely felt mathematical physics to be more exact than the sociological or psychological type of theory. Thus what worried me was neither the problem of truth, at that stage at least, nor the problem of exactness or measurability. It was rather that I felt that these other three theories, though posing as sciences, had in fact more in common with primitive myths than with science; that they resembled astrology rather than astronomy.

I found that those of my friends who were admirers of Marx, Freud, and Adler, were impressed by a number of points common to these theories, and especially by their apparent explanatory power. These theories appeared to be able to explain practically everything that happened within the fields to which they referred. The study of any of them seemed to have the effect of an intellectual conversion or revelation, opening your eyes to a new truth hidden from those not yet initiated. Once your eyes were thus opened you saw confirming instances everywhere: the world was full of verifications of the theory. Whatever happened always confirmed it. Thus its truth appeared manifest; and unbelievers were clearly people who did not want to see the manifest truth; who refused to see it, either because it was against their class interest, or because of their repressions which were still "un-analysed" and crying aloud for treatment.

The most characteristic element in this situation seemed to me the incessant stream of confirmations, of observations which "verified" the theories in question; and this point was constantly emphasized by their adherents. A Marxist could not open a newspaper without finding on every page confirming evidence for his interpretation of history; not only in the news, but also in its presentation-which revealed the class bias of the paper - and especially of course in what the paper did not say. The Freudian analysts emphasized that their theories were constantly verified by their "clinical observations." As for Adler, I was much impressed by a personal experience. Once, in 1919, I reported to him a case which to me did not seem particularly Adlerian, but which he found no difficulty in analysing in terms of his theory of inferiority feelings, although he had not even seen the child. Slightly shocked, I asked him how he could be so sure. "Because of my thousandfold experience," he replied; whereupon I could not help saying: "And with this new case, I suppose, your experience has become thousand-and-one-fold."

What I had in mind was that his previous observations may not have been much sounder than this new one; that each in its turn had been interpreted in the light of "previous experience," and at the same time counted as additional confirmation. What, I asked myself, did it confirm? No more than that a case could be interpreted in the light of the theory. But this meant very little, I reflected, since every conceivable case could be interpreted in the light of Adler's theory, or equally of Freud's. I may illustrate this by two very different examples of human behaviour: that of a man who pushes a child into the water with the intention of drowning it; and that of a man who sacrifices his life in an attempt to save the child. Each of these two cases can be explained with equal ease in Freudian and in Adlerian terms. According to Freud the first man suffered from repression (say, of some component of his Oedipus complex), while the second man had achieved sublimation. According to Adler the first man suffered from feelings of inferiority (producing perhaps the need to prove to himself that he dared to commit some crime), and so did the second man (whose need was to prove to himself that he dared to rescue the child). I could not think of any human behaviour which could not be interpreted in terms of either theory. It was precisely this fact - that they always fitted, that they were always confirmed - which in the eyes of their admirers constituted the strongest argument in favour of these theories. It began to dawn on me that this apparent strength was in fact their weakness.

With Einstein's theory the situation was strikingly different. Take one typical instance - Einstein's prediction, just then confirmed by the findings of Eddington's expedition. Einstein's gravitational theory had led to the result that light must be attracted by heavy bodies (such as the sun), precisely as material bodies were attracted. As a consequence it could be calculated that light from a distant fixed star whose apparent position was close to the sun would reach the earth from such a direction that the star would seem to be slightly shifted away from the sun; or, in other words, that stars close to the sun would look as if they had moved a little away from the sun, and from one another. This is a thing which cannot normally be observed since such stars are rendered invisible in daytime by the sun's overwhelming brightness; but during an eclipse it is possible to take photographs of them. If the same constellation is photographed at night one can measure the distances on the two photographs, and check the predicted effect.

Now the impressive thing about this case is the risk involved in a prediction of this kind. If observation shows that the predicted effect is definitely absent, then the theory is simply refuted. The theory is incompatible with certain possible results of observation - in fact with results which everybody before Einstein would have expected. This is quite different from the situation I have previously described, when it turned out that the theories in question were compatible with the most divergent human behaviour, so that it was practically impossible to describe any human behaviour that might not be claimed to be a verification of these theories.

These considerations led me in the winter of 1919-20 to conclusions which I may now reformulate as follows.

(1) It is easy to obtain confirmations, or verifications, for nearly every theory - if we look for confirmations.

(2) Confirmations should count only if they are the result of risky predictions; that is to say, if, unenlightened by the theory in question, we should have expected an event which was incompatible with the theory - an event which would have refuted the theory.

(3) Every "good" scientific theory is a prohibition: it forbids certain things to happen. The more a theory forbids, the better it is.

(4) A theory which is not refutable by any conceivable event is nonscientific. Irrefutability is not a virtue of theory (as people often think) but a vice.

(5) Every genuine test of a theory is an attempt to falsify it, or to refute it. Testability is falsifiability; but there are degrees of testability; some theories are more testable, more exposed to refutation, than others; they take, as it were, greater risks.

(6) Confirming evidence should not count except when it is the result of a genuine test of the theory; and this means that it can be presented as a serious but unsuccessful attempt to falsify the theory. (I now speak in such cases of "corroborating evidence.")

(7) Some genuinely testable theories, when found to be false, are still upheld by their admirers - for example by introducing ad hoc some auxiliary assumption, or by re-interpreting theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status. (I later described such a rescuing operation as a "conventionalist twist" or a "conventionalist stratagem. ")

One can sum up all this by saying that the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability.

II

I may perhaps exemplify this with the help of the various theories so far mentioned. Einstein's theory of gravitation clearly satisfied the criterion of falsifiability. Even if our measuring instruments at the time did not allow us to pronounce on the results of the tests with complete assurance, there was clearly a possibility of refuting the theory.

Astrology did not pass the test. Astrologers were greatly impressed, and misled, by what they believed to be confirming evidence so much so that they were quite unimpressed by any unfavourable evidence. Moreover, by making their interpretations and prophecies sufficiently vague they were able to explain away anything that might have been a refutation of the theory had the theory and the prophecies been more precise. In order to escape falsification they destroyed the testability of their theory. It is a typical soothsayer's trick to predict things so vaguely that the predictions can hardly fail: that they become irrefutable.

The Marxist theory of history, in spite of the serious efforts of some of its founders and followers, ultimately adopted this soothsaying practice. In some of its earlier formulations (for example in Marx's analysis of the character of the "coming social evolution') their predictions were testable, and in fact falsified.2 Yet instead of accepting the refutations the followers of Marx reinterpreted both the theory and the evidence in order to make them agree. In this way they rescued the theory from refutation; but they did so at the price of adopting a device which made it irrefutable. They thus gave a "conventionalist twist" to the theory; and by this stratagem they destroyed its much advertised claim to scientific status.

The two psycho-analytic theories were in a different class. They were simply non-testable, irrefutable. There was no conceivable human behaviour which could contradict them. This does not mean that Freud and Adler were not seeing certain things correctly: I personally do not doubt that much of what they say is of considerable importance, and may well play its part one day in a psychological science which is testable. But it does mean that those "clinical observations" which analysts naively believe confirm their theory cannot do this any more than the daily confirmations which astrologers find in their practice.3 And as for Freud's epic of the Ego, the Super-ego, and the Id, no substantially stronger claim to scientific status can be made for it than for Homer's collected stories from Olympus. These theories describe some facts, but in the manner of myths. They contain most interesting psychological suggestions, but not in a testable form.

At the same time I realized that such myths may be developed, and become testable; that historically speaking all - or very nearly all - scientific theories originate from myths, and that a myth may contain important anticipations of scientific theories. Examples are Empedocles' theory of evolution by trial and error, or Parmenides' myth of the unchanging block universe in which nothing ever happens and which, if we add another dimension, becomes Einstein's block universe (in which, too, nothing ever happens, since everything is, four dimensionally speaking, determined and laid down from the beginning). I thus felt that if a theory is found to be non-scientific, or "metaphysical" (as we might say), it is not thereby found to be unimportant, or insignificant, or "meaningless," or "nonsensical." it cannot claim to be backed by empirical evidence in the scientific sense - although it may easily be, in some generic sense, the "result of observation."

(There were a great many other theories of this pre-scientific or pseudo-scientific character, some of them, unfortunately, as influential as the Marxist interpretation of history; for example, the racialist interpretation of history - another of those impressive and all - explanatory theories which act upon weak minds like revelations.)

Thus the problem which I tried to solve by proposing the criterion of falsifiability was neither a problem of meaningfulness or significance, nor a problem of truth or acceptability. It was the problem of drawing a line (as well as this can be done) between the statements, or systems of statements, of the empirical sciences, and all other statements - whether they are of a religious or of a metaphysical character, or simply pseudo-scientific. Years later - it must have been in 1928 or 1929 - I called this first problem of mine the "problem of demarcation. " The criterion of falsifiability is a solution to this problem of demarcation, for it says that statements or systems of statements, in order to be ranked as scientific, must be capable of conflicting with possible, or conceivable, observations....

III

Let us now turn from our logical criticism of the psychology of experience to our real problem - the problem of the logic of science. Although some of the things I have said may help us here, in so far as they may have eliminated certain psychological prejudices in favour of induction, my treatment of the logical problem of induction is completely independent of this criticism, and of all psychological considerations. Provided you do not dogmatically believe in the alleged psychological fact that we make inductions, you may now forget my whole story with the exception of two logical points: my logical remarks on testability or falsifiability as the criterion of demarcation; and Hume's logical criticism of induction.

From what I have said it is obvious that there was a close link between the two problems which interested me at that time: demarcation, and induction or scientific method. It was easy to see that the method of science is criticism, i.e. attempted falsifications. Yet it took me a few years to notice that the two problems - of demarcation and of induction - were in a sense one....

I recently came across an interesting formulation of this belief in a remarkable philosophical book by a great physicist - Max Born's Natural Philosophy of Cause and Chance.5 He writes: "Induction allows us to generalize a number of observations into a general rule: that night follows day and day follows night . . .But while everyday life has no definite criterion for the validity of an induction, . . .science has worked out a code, or rule of craft, for its application." Born nowhere reveals the contents of this inductive code (which, as his wording shows, contains a "definite criterion for the validity of an induction"); but he stresses that "there is no logical argument" for its acceptance: "it is a question of faith"; and he is therefore "willing to call induction a metaphysical principle." But why does he believe that such a code of valid inductive rules must exist? This becomes clear when he speaks of the "vast communities of people ignorant of, or rejecting, the rule of science, among them the members of anti-vaccination societies and believers in astrology. It is useless to argue with them; I cannot compel them to accept the same criteria of valid induction in which I believe: the code of scientific rules." This makes it quite clear that "valid induction" was here meant to serve as a criterion of demarcation between science and pseudo-science.

But it is obvious that this rule or craft of "valid induction" is not even metaphysical: it simply does not exist. No rule can ever guarantee that a generalization inferred from true observations, however often repeated, is true. (Born himself does not believe in the truth of Newtonian physics, in spite of its success, although he believes that it is based on induction.) And the success of science is not based upon rules of induction, but depends upon luck, ingenuity,and the purely deductive rules of critical argument.

I may summarize some of my conclusions as follows:

(1) Induction, i.e. inference based on many observations, is a myth. It is neither a psychological fact, nor a fact of ordinary life, nor one of scientific procedure.

(2) The actual procedure of science is to operate with conjectures: to jump to conclusions - often after one single observation (as noticed for example by Hume and Born).

(3) Repeated observations and experiments function in science as tests of our conjectures or hypotheses, i.e. as attempted refutations.

(4) The mistaken belief in induction is fortified by the need for a criterion of demarcation which, it is traditionally but wrongly believed, only the inductive method can provide.

(5) The conception of such an inductive method, like the criterion of verifiability, implies a faulty demarcation.

(6) None of this is altered in the least if we say that induction makes theories only probable rather than certain.

If, as I have suggested, the problem of induction is only an instance or facet of the problem of demarcation, then the solution to the problem of demarcation must provide us with a solution to the problem of induction. This is indeed the case, I believe, although it is perhaps not immediately obvious.

For a brief formulation of the problem of induction we can turn again to Born, who writes: ". . . no observation or experiment, however extended can give more than a finite number of repetitions"; therefore, "the statement of a law - B depends on A - always transcends experience. Yet this kind of statement is made everywhere and all the time, and sometimes from scanty material.'

In other words, the logical problem of induction arises from (a) Hume's discovery (so well expressed by Born) that it is impossible to justify a law by observation or experiment, since it "transcends experience"; (b) the fact that science proposes and uses laws "everywhere and all the time." (Like Hume, Born is struck by the "scanty material," i.e. the few observed instances upon which the law may be based.) To this we have to add (c) the principle of empiricism which asserts that in science, only observation and experiment may decide upon the acceptance or rejection of scientific statements, including laws and theories.

These three principles, (a), (b), and (c), appear at first sight to clash; and this apparent clash constitutes the logical problem of induction.

Faced with this clash, Born gives up (c), the principle of empiricism (as Kant and may others, including Bertrand Russell, have done before him), in favour of what he calls a "metaphysical principle"; a metaphysical principle which he does not even attempt to formulate; which he vaguely describes as a "code or rule of craft"; and of which I have never seen any formulation which even looked promising and was not clearly untenable.

But in fact the principles (a) to (c) do not clash. We can see this the moment we realize that the acceptance by science of a law or of a theory is tentative only; which is to say that all laws and theories are conjectures, or tentative hypotheses (a position which I have sometimes called "hypotheticism") and that we may reject a law or theory on the basis of new evidence, without necessarily discarding the old evidence which originally led us to accept it.7

The principles of empiricism (c) can be fully preserved, since the fate of a theory, its acceptance or rejection, is decided by observation and experiment by the result of tests. So long as a theory stands up to the severest tests we can design, it is accepted; if it does not, it is rejected. But it is never inferred, in any sense, from the empirical evidence. There is neither a psychological nor a logical induction. Only the falsity of the theory can be inferred from empirical evidence, and this inference is a purely deductive one.

Hume showed that it is not possible to infer a theory from observation statements; but this does not affect the possibility of refuting a theory by observation statements. The full appreciation of the possibility makes the relation between theories and observations perfectly clear. This solves the problem of the alleged clash between the principles (a), (b), and(c), and with it Hume's problem of induction....

NOTES

1. This is a slight oversimplification, for about half of the Einstein effect may be derived from the classical theory, provided we assume a ballistic theory of light.

2. See for example, my Open Society and Its Enemies, ch. 15, section iii, and notes 13-14.

3. "Clinical observations," like all other observations, are interpretations in the light of theories; and for this reason alone they are apt to seem to support those theories in the light of which they were interpreted. But real support can be obtained only from observations undertaken as tests (by "attempted refutations"); and for this purpose criteria of refutation have to be laid down beforehand; it must be agreed which observable situations, if actually observed, mean that the theory is refuted. But what kind of clinical responses would refute to the satisfaction of the analyst not merely a particular analytic diagnosis but psycho-analysis itself? And have such criteria ever been discussed or agreed upon by analysts? Is there not, on the contrary, a whole family of analytic concepts, such as "ambivalence" (l do not suggest that there is no such thing as ambivalence), which would make it difficult, if not impossible, to agree upon such criteria? Moreover, how much headway has been made in investigating the question of the extent to which the (conscious or unconscious) expectations and theories held by the analyst influence the "clinical responses" of the patient? To say nothing about the conscious attempts to influence the patient by proposing interpretations to him, etc.) Years ago I introduced the term "Oedipus effect" to describe the influence of a theory or expectation or prediction upon the event which it predicts or describes: it will be remembered that the causal chain leading to Oedpus' parricide was started by the oracle's prediction of this event. This is a characteristic and recurrent theme of such myths, but one which seems to have failed to attract the interest of the analysts, perhaps not accidentally. (The problem of confirmatory dreams suggested by the analyst is discussed by Freud, for example in Gesammelte Schriften,i 111, 1925, where he says on p. 314: "If anybody asserts that most of the dreams which can be utilized in an analysis . . . owe their origin to [the analyst's] suggestion, then no objection can be made from the point of view of analytic theory. Yet there is nothing in this fact," he surprisingly adds, "which would detract from the reliability of our results."]

4. The case of astrology, nowadays a typical pseudo-science, may illustrate this point. It was attacked, by Aristotelians and other rationalists, down to Newton's day, for the wrong reason - for its now an accepted assertion that the planets had an "influence" upon terrestrial ("sublunar") events. In fact Newton's theory of gravity, and especially the lunar theory of the tides, was historically speaking an offspring of astrological lore. Newton, it seems, was most reluctant to adopt a theory which came from the same stable as for example the theory that "influenza" epidemics are due to an astral "influence." And Galileo, no doubt for the same reason, actually rejected the lunar theory of the tides; and his misgivings about Kepler may easily be explained by his misgivings about astrology.

5. Max Born, Natural Philosophy of Cause and Chance, Oxford, 1949, p. 7.

6. Natural Philosophy of Cause and Chance, p. 6.

7. I do not doubt that Born and many others would agree that theories are accepted only tentatively. But the widespread belief in induction shows that the far-reaching implications of this view are rarely seen.

http://cla.calpoly.edu/~fotoole/321.1/popper.html

[Plasmatic]

We all - the small circle of students to which I belonged - were thrilled with the result of Eddington's eclipse observations which in 1919 brought the first important confirmation of Einstein's theory of gravitation. It was a great experience for us, and one which had a lasting influence on my intellectual development.

This says it all for me. It is the acceptance that certain observations "confirm" nonsensical theories not truly understood conceptually by those doing the accepting, that causes folks to dive in head first into the deep. Thats what happened to me when I heard that light was "proven" to be both wave and particle.

[Grey Cloud]

I see Popper as part of the problem not as part of the solution.
1. He uses Marx, Einstein, Freud and Adler to illustrate his points but Popper himself comes from the same historical-cultural milieu. All of them (Marxism, science and psychology) involve elites knowing what is best for the masses. Does Popper honestly think that his mindset is superior to everyone elses? This same period also produced Goethe and Nietzsche but they sang a different song and so were marginalised.
2. Popper (and many others) criticise science and its methods but still maintain that science is superior to other modes of investigation and mankind's best hope of getting at the truth. Every generation of scientists since the Enlightenment has been convinced that their's was virtually the last word in understanding and knowledge; that their's was the ultimate in intellect. Meanwhile the Universe carries on working like it always has - regardless as to whether it is supposed to doing so according to Newtonian, Einsteinian, Quantum or Electric 'Laws'.
3. Popper and his ilk as so entrenched in their (western) cultural, modernist superiority that they cannot even imagine they might have something to learn from say, China or India - let alone anyone from the past.
4. Popper calls astrology pseudo-science. 'Science' and pseudo-science' are modern terms. This is a typical move much used by modrn experts, so-called. Stick a modern label on something not modern and then criticise it for not measuring up to the label. The rationale behind astrology is quite simple and to me at least, quite logical. I am here talking about astrology as practiced by the ancients not the stuff in the newspapers and magazines.
5. Popper:

At the same time I realized that such myths may be developed, and become testable; that historically speaking all - or very nearly all - scientific theories originate from myths, and that a myth may contain important anticipations of scientific theories. Examples are Empedocles' theory of evolution by trial and error, or Parmenides' myth of the unchanging block universe in which nothing ever happens and which, if we add another dimension, becomes Einstein's block universe (in which, too, nothing ever happens, since everything is, four dimensionally speaking, determined and laid down from the beginning).

This segement is an excellent example of the conceit I mentioned in (1) above. First the myths have to be 'developed' to become 'testable' - why? Why not approach them on their own terms? Frightened of learning something?
His choice of Empedocles and Parmenides is interesting. Empedocles is one of the most enigmatic of the presocratics and not one to be summed up as lightly as does Popper here. For the standard academic views see:
http://plato.stanford.edu/entries/empedocles/#1
http://www.utm.edu/research/iep/e/empedocl.htm
http://classicpersuasion.org/pw/empedocles/
http://history.hanover.edu/texts/presoc/emp.htm
For a recent alternative see:
http://www.theosophy-nw.org/theosnw/wor ... ngsley.htm
http://www.peterkingsley.org/pages.cfm?ID=7
http://en.wikipedia.org/wiki/Peter_Kingsley_(scholar)
My personal jury is still out on Kingsley but he deals with Empedocles and Parmenides.
Parmenides' universe is not an 'unchanging block universe in which nothing ever happens'. See any of the URLs above for Parmenides.

Let science continue to invent its latest planet polluting marvels; I'll stick with the ancients.

[bboyer]

Several philosophers and historians of science have, however, argued that Popper's definition of theory as a set of falsifiable statements is wrong [3] because, as Philip Kitcher has pointed out, if one took a strictly Popperian view of "theory", observations of Uranus when first discovered in 1781 would have "falsified" Newton's celestial mechanics. Rather, people suggested that another planet influenced Uranus' orbit—and this prediction was indeed eventually confirmed.

Kitcher agrees with Popper that "there is surely something right in the idea that a science can succeed only if it can fail". [4] He also takes into account Hempel and Quine's critiques of Popper, to the effect that scientific theories include statements that cannot be falsified (presumably what Hawking alluded to as arbitrary elements), and the point that good theories must also be creative. He insists that we view scientific theories as consisting of an "elaborate collection of statements", some of which are not falsifiable, while others—those he calls "auxiliary hypotheses", are.

According to Kitcher, good scientific theories must have three features:

1. Unity: "A science should be unified…. Good theories consist of just one problem-solving strategy, or a small family of problem-solving strategies, that can be applied to a wide range of problems" (1982: 47).
2. Fecundity: "A great scientific theory, like Newton's, opens up new areas of research…. Because a theory presents a new way of looking at the world, it can lead us to ask new questions, and so to embark on new and fruitful lines of inquiry…. Typically, a flourishing science is incomplete. At any time, it raised more questions than it can currently answer. But incompleteness is now vice. On the contrary, incompleteness is the mother of fecundity…. A good theory should be productive; it should raise new questions and presume that those questions can be answered without giving up its problem-solving strategies" (1982: 47–48).
3. Auxiliary hypotheses that are independently testable: "An auxiliary hypothesis ought to be testable independently of the particular problem it is introduced to solve, independently of the theory it is designed to save" (1982: 46) (e.g. the evidence for the existence of Neptune is independent of the anomalies in Uranus's orbit).

Like other definitions of theories, including Popper's, Kitcher makes it clear that a good theory includes statements that have (in his terms) "observational consequences". But, like the observation of irregularities in the orbit of Uranus, falsification is only one possible consequence of observation. The production of new hypotheses is another possible—and equally important—observational consequence.

(continues at) http://en.wikipedia.org/wiki/Theory

[Plasmatic]

I certainly do not subscribe to Popper. His scepticism of induction is laughable. In this respect he is "part of the problem".

[bboyer]

An interesting bit of synchronicity here.

[quote="May 13, 2008 in "Whatever happened to real science?" Wal Thornhill"]

....

It is not clear how people could conclude that Popper “identified [falsification] as the defining characteristic of real science” if they actually read The Logic of Scientific Discovery. The book is about the logic associated with the discovery of new ideas; the title is not The Objective Characteristics of a Reified Abstraction. He clearly presents looking for false entailments as a convention. (That’s actually a quote from Popper on p. 37— “convention.”: Falsifiability “will accordingly have to be regarded as a proposal for an agreement or convention.” [Emphasis in original]. That is, an agreement not to “adjust” a theory but to consider any variation as an entirely new theory that must compete with all available alternatives and to admit that the old version was falsified.)

The book is not so much about science as about an attitude—an eagerness to discover and to test new ideas rather than to defend an established dogma against life’s inevitable changes. On the next page, Popper writes:

“Thus I freely admit that in arriving at my proposals I have been guided, in the last analysis, by value judgments and predilections. But I hope that my proposals may be acceptable to those who value not only logical rigour but also freedom from dogmatism; who seek practical applicability, but are even more attracted by the adventure of science, and by discoveries which again and again confront us with new and unexpected questions, challenging us to try out new and hitherto undreamed-of answers.”

....

(article continues at Whatever happened to real science?)

With appreciation to Mel Acheson for his contribution.

[/quote]

[bboyer]

A paper by Prof. Don Scott, Statistics – Tool or Weapon? The application and misapplication of Bayes’ theorem.

http://www.electric-cosmos.org/Bayes.pdf

[quote="In "Statistics - Tool or Weapon", Don Scott"]There is an old saying: “Statistics don‟t lie… but statisticians sometimes do.” This maxim is a corollary of the well known fact that "Garbage In produces Garbage Out‟ (GIGO). It reaffirms the observation that, no matter how sophisticated any given computer program may be, if you feed it input data that is flawed, the output you will get will also be flawed. Despite this however, most people are usually impressed by complication: the more complicated the computerized algorithm, the more persuasive the results are for anyone who is gullible. The effectiveness of complicated statistics is a case in point.

Most of us have heard the terms a priori and a posteriori and know they refer respectively to things that precede or follow an event. But most people do not know how to calculate nor to interpret an 'a posteriori probability' even though they may have occasionally heard that term. Such quantities are often used in science and we ought to know how to interpret them and how to judge the appropriateness of using them. For this we can turn to Bayes' theorem.

Bayes' theorem (BT) is a statistical principle that is quite enlightening if properly applied. But as with many powerful tools, it can be dangerous if it is misused. BT was specifically developed to answer questions about the validity of tests.

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[Plasmatic]

The book is not so much about science as about an attitude—an eagerness to discover and to test new ideas rather than to defend an established dogma against life’s inevitable changes. On the next page, Popper writes:

“Thus I freely admit that in arriving at my proposals I have been guided, in the last analysis, by value judgments and predilections. But I hope that my proposals may be acceptable to those who value not only logical rigour but also freedom from dogmatism; who seek practical applicability, but are even more attracted by the adventure of science, and by discoveries which again and again confront us with new and unexpected questions, challenging us to try out new and hitherto undreamed-of answers.”

Certainly not what I was referring to about Popper. I wouldnt argue with that idea. I think Michael Gmirkin tag says it best "not to explain the uninvestigated" I would add that science is dependant on the fact that there are "laws" that do not "change"

[Plasmatic]

For info on Poppers skepticism non-sense try this:

http://www.geocities.com/ResearchTriang ... opper.html

"The Logic of Scientific Discovery", indeed! There is scarcely a word in it, or in anything else Popper ever wrote, about scientific discovery, and the reason is as simple as it is sufficient. "Discovery" is a success-word, and of the strongest kind: it means the same as "discovery of what is true or of what exists". The history of science, therefore, to the extent that it has been a history of discovery---as it has been so markedly in the last four hundred years, for example---is a history of success. But that is not the way that Popper sees the history of science, far from it. For him the history of science is a succession of `problems', `conjectures and refutations', Socratic or Pre-Socratic dialogues, `critical discussions'. It is all talk. In this context any vivid reminder of an actual scientific discovery would be as out of place as a hippopotamus in a philosophy class. The only thing worse would be a reminder (though this would be too horrible) of what whig historiography used so often to bracket with scientific discoveries: inventions. Popper is perhaps the first person to see, in the glorious history of scientific discovery, nothing more productive and exhilarating than a huge W.E.A. philosophy class, and one which, to add to its charms, might go on forever. Does anyone suppose that Popper ever wrote or meant to write a book for which a non-misleading title would have been "The Logic of Scientific Discovery of Truth, or of what Exists"? Yet that is a purely analytic extension, only objectionable on aesthetic grounds, of his actual title. But clearly this title would belong, in the history of thought about science, in the heyday of the `whig supremacy', probably somewhere between J.S.Mill and Samuel Smiles, and it sounds a good deal more like the latter than the former.
No, the right title for that book---and it is of some importance to realize that I am here only saying what everyone familiar with its contents has been at least half-conscious of all along---would have been "The `Logic' of Scientific `Discovery'". But of course that would have been too openly irrationalist. Better to let the word "discovery" stand, and trust to the contents of the book, rather than to quotation-marks in the title, to neutralize the unintended implication of success. Which duly happened, and never a word said.
It is the word "knowledge", however, which was the target of Popper's most remarkable feat of neutralization. This word bulks large in his philosophy of science (much larger than "discovery"), and in recent years, in particular, the phrase "the growth of knowledge" has been a favorite with him and with those he has influenced most. Some people have professed to find a difficulty, indeed, in understanding how there can be a growth-of-knowledge and yet no accumulation-of-knowledge. But then some people cannot or will not understand the simplest thing, and we cannot afford to pause over them. Let us just ask, how does Popper use the word "knowledge"?
Well, often enough, of course, like everyone else including our other authors, he uses it with its normal success-grammar. But when he wishes to give expression to his own philosophy of science he baldly neutralizes it. Scientific knowledge, he then tells us, is "conjectural knowledge". Nor is this shocking phrase a mere slip of the pen, which is what anywhere else it would be thought to be. On the contrary, no phrase is more central to Popper's philosophy of science, or more insisted upon by him. The phrase even furnishes, he believes, and as the title of one of his articles claims, nothing less than the "solution to the problem of induction" [28 ].
In one way this is true, and must be true, because any problem clearly must yield before some one who is prepared to treat language in the way Popper does. What problem could there be so hard as not to dissolve in a sufficiently strong solution of nonsense? And nonsense is what the phrase "conjectural knowledge" is: just like say, the phrase "a drawn game which was won". To say that something is known, or is an object of knowledge, implies that it is true, and known to be true. (Of course only `knowledge that' is in question here). To say of something that it is conjectural, on the other hand, implies that it is not known to be true. And this is all that needs to be said on the celebrated subject of "conjectural knowledge"; and is a great deal more than should need to be said.

Popper certainly is part of the "problem". In fact Ive just discovered a specific target for research in the Philosophy of Science.

[Grey Cloud]

Popper is perhaps the first person to see, in the glorious history of scientific discovery, nothing more productive and exhilarating than a huge W.E.A. philosophy class, and one which, to add to its charms, might go on forever.

Can someone tell me what W.E.A. is, please? I'm guessing it's some sort of Americanism.

[Plasmatic]

Not sure on that myself G.C . Although i think its non essential to the statement as such.

Heres another quote:

A scientific theory, Popper never tires of reminding his readers, is never certain in relation to, or in other words deducible from, those propositions that constitute (in most people's eyes) the reasons to believe it. Of course I do not cite this as an irrationalist thesis. It is only a fallibilist one: it asserts no more than the logical possibility of the conjunction of the evidence for any given scientific theory, with the negation of that theory. This thesis is so far from being one which is peculiar to the authors with whom we are concerned, that it is nowadays a commonplace with almost all philosophers of science. But Popper goes much further than this. It is a favorite thesis with him that a scientific theory is, not only never certain, but never even probable, in relation to the evidence for it . More than that: a scientific theory, he constantly says, cannot even be more probable, in relation to the empirical evidence for it, than it is a priori, or in the absence of all empirical evidence .
These two theses will be acknowledged to be irrationalist enough; and they are ones upon which Popper repeatedly insists. He goes much further still, however. The truth of any scientific theory or law-statement, he constantly says, is exactly as improbable, both a priori and in relation to any possible evidence, as the truth of a self-contradictory proposition ; or, to put the matter in plain English (as Popper does not), it is impossible.
Again: scientific knowledge is usually thought to have at least some connection with rational belief, but Popper writes: "Belief, of course, is never rational: it is rational to suspend belief" . One hardly knows what to wonder at more here, the thesis itself, or the arrogance of the author's "of course". His thesis, as will be evident, goes far beyond the philosophy of science. But it certainly does go as far as that, and will be admitted to express, in that domain, an irrationalism sufficiently uncompromising.
Again: Popper endorses the notorious sceptical thesis of Hume concerning inductive arguments, or arguments from the observed to the unobserved. This is the thesis that no proposition about the observed is a reason to believe any contingent proposition about the unobserved; or in other words, that the premise of an inductive argument is never a reason to believe its conclusion. Popper constantly and emphatically, and with detailed references to Hume, expresses his assent to this thesis. He writes, for example: "I agree with Hume's opinion that induction is invalid and in no sense justified" . And again: "Are we rationally justified in reasoning from repeated instances of which we have experience to instances of which we have had no experience? Hume's unrelenting answer is: No, we are not justified [...] My own view is that Hume's answer to this problem is right [...]" . There are many other statements by Popper to exactly the same effect .
Scepticism about induction is an irrationalist thesis itself, but its irrationalist character is enormously amplified if it is combined, as it is in Hume and in Popper, with the thesis of empiricism: that is, with the thesis that no propositions other than propositions about the observed can be a reason to believe a contingent proposition about the unobserved. For then it follows at once (since inductive scepticism says that there can be no reason from experience), that there can be no reason at all, to believe any contingent propositions about the unobserved: which class of propositions includes, of course, all scientific theories. Hume, being an empiricist, did draw from his inductive scepticism this even more irrationalist conclusion: `scepticism about the unobserved', as we may call it. And Popper, for the same reason, does the same.
Hume's inductive scepticism, while it is an irrationalist thesis among others in Popper's philosophy of science, is also more than that: it is one on which all the others logically depend. Whenever Popper undertakes, as he often does, to explain the grounds of his philosophy of science, and especially of whatever is most irrationalist in it, the reader is sure to meet with yet another of Popper's expositions, with detailed reference to Hume's writings and with unqualified endorsement of Hume's scepticism about induction [10 ]. If we take any other representative expression of Popper's irrationalism (for example, those mentioned above in the second to the sixth paragraph of this section), and ask ourselves "Why does Popper believe this?", then part at least of the answer is always the same, and always obvious. It is because he shares Hume's scepticism about induction.

[Grey Cloud]

From the pen of the last true philosopher:

Let us look more closely: what is the man of science? An ignoble species of man for a start, with the virtues of an ignoble, that is to say subservient, unauthorative and un-selfsufficent species of man: he possesses industriousness, patient acknowledgement of his proper place in the rank and file, uniformity and moderation in abilities and requirements, he possesses the instinct for his own kind and for that which his own kind have need of, for example that little bit of independence and green pasture without which there is no quiet work, that claim to honour and recognition (which first and foremost presupposes recognizability-), that sunshine of good name… (p133)

Perhaps he is troubled by his health or by the pettiness and stuffiness of his wife and friends, or by a lack of companions and company- yes, he forces himself to reflect on his troubles: but in vain! Already his thoughts are roaming, off to a more general case, and tomorrow he will know as little how to help himself as he did yesterday. (p134)

Friedrich Nietzsche, Beyond Good and Evil.

[Plasmatic]

Ah the hopeless introvert of self abnegation.

[Grey Cloud]

Ah the hopeless introvert of self abnegation.

Is that a quote from someone or an attempt at irony? Don't quite see how any of it fits Nietzsche.

P.S. I was just curious about the W.E.A thing as I hadn't come across it before.

[Plasmatic]

easy now , I see my comparison is lost on you , thats O.K.....Im curious About the acronym myself.