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When first published in , this book revolutionized contemporary thinking about science and knowledge It remains the one of the most widely read books about science to come out of the twentieth centuryNote: the book was first published in , in German, with the title Logik der Forschung It was reformulated into English inSee Wikipedia for details

10 thoughts on “Logik der Forschung

  1. Roy Lotz Roy Lotz says:

    We do not know: we can only guess.

    Karl Popper originally wrote Logik der Forchung (The Logic of Research) in 1934. This original version—published in haste to secure an academic position and escape the threat of Nazism (Popper was of Jewish descent)—was heavily condensed at the publisher’s request; and because of this, and because it remained untranslated from the German, the book did not receive the attention it deserved. This had to wait until 1959, when Popper finally released a revised and expanded English translation. Yet this condensation and subsequent expansion have left their mark on the book. Popper makes his most famous point within the first few dozen pages; and much of the rest of the book is given over to dead controversies, criticisms and rejoinders, technical appendices, and extended footnotes. It does not make for the most graceful reading experience.

    This hardly matters, however, since it is here that Popper put forward what has arguably become the most famous concept in the philosophy of science: falsification.

    This term is widely used; but its original justification is not, I believe, widely understood. Popper’s doctrine must be seen as a response to inductivism. In 1620 Francis Bacon released his brilliant Novum Organum. Its title alludes to Aristotle’s Organon, a collection of logical treatises, mainly focusing on how to make accurate deductions. This Aristotelian method—dominated by syllogisms: deriving conclusions from given premises—dominated the study of nature for millennia, with precious little to show for it. Francis Bacon hoped to change all that with his new doctrine of induction. Instead of beginning with premises (‘All men are mortal’), and reasoning to conclusions (‘Socrates is mortal’), the investigator must begin with experiences (‘Socrates died,’ ‘Plato died,’ etc.) and then generalize a conclusion (‘All men are mortal’). This was how science was to proceed: from the specific to the general.

    This seemed all fine and dandy until, in 1738, David Hume published his Treatise of Human Nature, in which he explained his infamous ‘problem of induction.’ Here is the idea. If you see one, two, three… a dozen… a thousand… a million white swans, and not a single black one, it is still illogical to conclude “All swans are white.” Even if you investigated every swan in the world but one, and they all proved white, you still could not conclude with certainty that the last one would be white. Aside from modus tollens (concluding from a negative specific to a negative general), there is no logically justifiable way to proceed from the specific to the general. To this argument, many are tempted to respond: “But we know from experience that induction works. We generalize all the time.” Yet this is to use induction to prove that induction works, which is paradoxical. Hume’s problem of induction has proven to be a stumbling block for philosophers ever since.

    In the early parts of the 20th century, the doctrine of logical positivism arose in the philosophical world, particularly in the ‘Vienna Circle’. This had many proponents and many forms, but the basic idea, as explained by A.J. Ayer, is the following. The meaning of a sentence is equivalent to its verification; and verification is performed through experience. Thus the sentence “The cat is on the mat” can be verified by looking at the mat; it is a meaningful utterance. But the sentence “The world is composed of mind” cannot be verified by any experience; it is meaningless. Using this doctrine the positivists hoped to eliminate all metaphysics. Unfortunately, however, the doctrine also eliminates human knowledge, since, as Hume showed, generalizations can never be verified. No experience corresponds, for example, to the statement: “Gravitation is proportional to the product of mass and the inverse square of distance,” since this is an unlimitedly general statement, and experiences are always particular.

    Karl Popper’s falsificationism is meant to solve this problem. First, it is important to note that Popper is not, like the positivists, proposing a criterion of ‘meaning’. That is to say that, for Popper, unfalsifiable statements can still be meaningful; they just do not tell us anything about the world. Indeed, he continually notes how metaphysical ideas (such as Kepler’s idea that circles are more ‘perfect’ than other shapes) have inspired and guided scientists. This is itself an important distinction because it prevents him from falling into the same paradox as the positivists. For if only the statements with empirical content have meaning, then the statement “only the statements with empirical content have meaning” is itself meaningless. Popper, for his part, regarded himself as the enemy of linguistic philosophy and considered the problem of epistemology quite distinct from language analysis.

    To return to falsification, Popper’s fundamental insight is that verification and falsification are not symmetrical. While no general statement can be proved using a specific instance, a general statement can indeed be disproved with a specific instance. A thousand white swans does not prove all swans are white; but one black swan disproves it. (This is the aforementioned modus tollens.) All this may seem trivial; but as Popper realized, this changes the nature of scientific knowledge as we know it. For science, then, is far from what Bacon imagined it to be—a carefully sifted catalogue of experiences, a collection of well-founded generalizations—and is rather a collection of theories which spring up, as it were, from the imagination of the scientist in the hopes of uniting several observed phenomena under one hypothesis. Or to put it more bluntly: a good scientific theory is a guess that does not prove wrong.

    With his central doctrine established, Popper goes on to the technicalities. He discusses what composes the ‘range’ or ‘scope’ of a theory, and how some theories can be said to encompass others. He provides an admirable justification for Occam’s Razor—the preference for simpler over more complex explanations—since theories with fewer parameters are more easily falsified and thus, in his view, more informative. The biggest section is given over to probability. I admit that I had some difficulty following his argument at times, but the gist of his point is that probability must be interpreted ‘objectively,’ as frequency distributions, rather than ‘subjectively,’ as degrees of certainty, in order to be falsifiable; and also that the statistical results of experiments must be reproducible in order to avoid the possibility of statistical flukes.

    All this leads up to a strangely combative section on quantum mechanics. Popper apparently was in the same camp as Einstein, and was put off by Heisenberg’s uncertainty principle. Like Einstein, Popper was a realist and did not like the idea that a particle’s properties could be actually undetermined; he wanted to see the uncertainty of quantum mechanics as a byproduct of measurement or of ‘hidden variables’—not as representing something real about the universe. And like Einstein (though less famously) Popper proposed an experiment to decide the issue. The original experiment, as described in this book, was soon shown to be flawed; but a revised experiment was finally conducted in 1999, after Popper’s death. Though the experiment agreed with Popper’s prediction (showing that measuring an entangled photon does not affect its pair), it had no bearing on Heisenberg’s uncertainty principle, which restricts arbitrarily precise measurements on a single particle, not a pair of particles.

    Incidentally, it is difficult to see why Popper is so uncomfortable with the uncertainty principle. Given his own dogma of falsifiability, the belief that nature is inherently deterministic (and that probabilistic theories are simply the result of a lack of our own knowledge) should be discarded as metaphysical. This is just one example of how Popper’s personality was out of harmony with his own doctrines. An advocate of the open society, he was famously authoritarian in his private life, which led to his own alienation. This is neither here nor there, but it is an interesting comment on the human animal.

    Popper’s doctrine, like all great ideas, has proven both influential and controversial. For my part I think falsification a huge advance over Bacon’s induction or the positivists’ verification. And despite the complications, I think that falsifiability is a crucial test to distinguish, not only science from pseudo-science, but all dependable knowledge from myth. For both pseudo-science and myth generally distinguish themselves by admirably fitting the data set, but resisting falsification. Freud’s theories, for example, can accommodate themselves to any set of facts we throw at them; likewise for intelligent design, belief in supernatural beings, or conspiracy theories. All of these seem to explain everything—and in a way they do, since they fit the observable data—but really explain nothing, since they can accommodate any new observation.

    There are some difficulties with falsification, of course. The first is observation. For what we observe, or even what we count as an ‘observation’, is colored by our background beliefs. Whether to regard a dot in the sky as a plane, a UFO, or an angel is shaped by the beliefs we already hold; thus it is possible to disregard observations that run counter to our theories, rather than falsifying the theories. What is more, theories never exist in isolation, but in an entire context of beliefs; so if one prediction is definitively falsified, it can still be unclear what we must change in our interconnected edifice of theories. Further, it is rare for experimental predictions to agree exactly with results; usually they are approximately correct. But where do we draw the line between falsification and approximate correctness? And last, if we formulate a theory which withstands test after test, predicting their results with extreme accuracy time and again, must we still regard the theory as a provisional guess?

    To give Popper credit, he responds to all of these points in this work, though perhaps not with enough discussion. But all these criticisms belie the fact that so much of the philosophy of science written after Popper has taken his work as a starting point, either attempting to amplify, modify, or (dare I say it?) falsify his claims. For my part, though I was often bored by the dry style and baffled by the technical explanations, I found myself admiring Popper’s careful methodology: responding to criticisms, making fine distinctions, building up his system piece by piece. Here is a philosopher deeply committed to the ideal of rational argument and deeply engaged with understanding the world. I am excited to read more.

  2. Laura Laura says:

    If it was 400 pages shorter, I'd give it 5 stars.

    Popper makes his point quickly and emphatically on the merits of deductive reasoning versus inductive and its use in scientific research. Unfortunately, he continues to give examples to reiterate his point. Reading the first 50 pages is good enough. But, it's a good book for any and all graduate students in the scientific field to have on a bookshelf (particularly at the bench).

  3. Anna Anna says:

    I define the empirical content of a statement p as the class of its potential falsifiers. The logical content is defined, with the help of the concept of derivability, as the class of all non-tautological statements which are derivable from the statement in question. So the logical content of p is at least equal to that of a statement q, if q is derivable from p.

    If you liked that, you'll looooove this book!

  4. Maica Maica says:

    Strictly to be confined within the realms of the scientific disciplines. But as far as other realms of human activity are concerned, the methodology espoused here is to be taken in caution.

  5. Robb Robb says:

    I volunteered to read this book in my PhD Doctoral Seminar because I thought my German language abilities would help me further understand Karl Popper.

    It didn't.

    Here's my review:

    Grappling with underlying ideas of how science is “discovered” and the underlying problems that exist with new knowledge? Sir Karl Popper’s book, The Logic of Scientific Discovery, directly addresses these issues and additionally tackles a theme important to philosophy – epistemology or the growth of knowledge. A critical examination of the logic behind science is required for the “growth of scientific knowledge.”

    Popper’s book, published in the early 1930s, elicited a storm of controversy. In fact, the author has since written three novels as well as numerous papers to further explain his views. The premise he makes is that laws of nature, theories and hypotheses should not be and never should be established as “truth”. Instead, they can be corroborated and supported by the observations and systematic tests of science.

    Of the three organized parts to the book, the first part deals with an introduction to the Logic of Science. The second section, by far the largest, begins to expound upon different components needed to frame his overall thesis. Together, these are arranged into short monologues (85 of them) that dissect the components of theoretical scientific research. The last section of his book contains seven appendices as well as twelve additional appendices added since his first edition. These contain examples and explicit rationale to elaborate upon and delve into those items that he felt would be the most contentious or have since been found contentious by his peers.

    In short, he spends most of his time reviewing some of the more fundamental problems that philosophers have encountered (and often have chosen to ignore) in the advancement of science. He takes aim at the generally accepted “theory of scientific method”, arguing that most methodological rules, conventions, and approaches taken contain fundamental flaws. Beginning with the theories in use, he observes that the logical problems, often dismissed by assumption or by convention, should not and do not need to be handled in this way. The notion of falsification and the problem of empirical basis are thoroughly discussed. A great deal of space is devoted to the nuances of testability and simplicity followed by two dozen or so pieces on probability. His “Observations on Quantum Theory” are fascinating as he walks the reader through many of theory’s questionable assumptions. Finally, he finishes with several thoughts on “corroboration, or how a theory stands up to tests.”

    This book is NOT light reading – a good dictionary to assist with the mastery of his subject area is highly recommended. In addition, a college-level education in the empirical sciences and philosophy wouldn’t hurt. Figures such as Kant, Bernoulli, Newton, Einstein and others are used throughout the book to support or reject his theses. He is well versed in his contemporaries’ work and speaks with an ease regarding their research and theories in a way that lends credence to his own views. Contemporaries such as Einstein, with whom he corresponded, were equally familiar and knowledgeable with accepted philosophical tenets as well as in their particular fields of science. Unfortunately, the book’s flow and organization leaves much to be desired. For example, Popper chose to footnote and comment on nearly every monologue he wrote in subsequent editions. (The original had been printed near the beginning of his career.) For many, this is a great boon, because he uses this space to defend his work over time as well as expound even further upon his thoughts. He also acknowledges his mistakes or where he has been convinced otherwise and even encourages readers to skip portions of the book he no longer supports. Publishing a revised and enlarged edition to correct his work might have made things easier for the reader. However, this artifact may simply be a way to show how his thinking has evolved over the years.

    Owing to the radically provocative nature of his ideas, the many separate books, papers, and symposia this book has spawned, this book has fulfilled its purpose. It has become one of the classics in modern logical thinking by critically examining the underpinnings of modern scientific thought and theory. This book deserves a place in the library of every serious student of philosophy. While writing about logical examination of scientific theories, Popper muses, “Our method of research is not to defend them, in order to prove how right we were. On the contrary, we try to overthrow them.” In essence, his legacy remains: there will always be another set of laws, another set of hypotheses and their accompanying axioms that will absorb existing theories and well established axioms until the next set comes along. And we still have so much to discover.

  6. Richard Richard says:

    I studied this while in grad school. My thesis, which never got much beyond the notes stage, used Popper and other epistemologies to examine the difference between natural sciences and social sciences. The basic hypothesis was that the latter rested on essentially contested propositions. For example, Galileo's observations of the solar system and the conclusions he drew therefrom depended on the underlying theory of optics being correct. Since both the theory and instruments were new and crude, that was originally probably a pretty formidable attack. However, there is nothing about whether or not the theory of optics is correct that is a direct affront to anyone's ideological holdings. Meanwhile, over in the social sciences, my suspicion is that there will always be unresolvable debates about the essence of things: which is more important, charity or justice? Seniority or quantifiable capability?

    Popper provided the foundation for much of my thinking, and more. But my thesis advisor thought I was straying pretty far from International Relations and I was finding there was too much more recent epistemology to be read to sustain my interest.

    I still think I'm right :-) but it doesn't really matter, does it?

  7. Peter (Pete) Mcloughlin Peter (Pete) Mcloughlin says:

    This book gets five stars simply on influence on subsequent philosophers of science. This famous work has Popper explaining a methodology of science based on the falsification principle as opposed to the Vienna Circle's verification principle. It is a superior incite that in one stroke explains how hard sciences (which serves as its model) are done and at the same times solves the demarcation problem in distinguishing between whether a concept is scientific or not. The falsification principle is a principle that a scientific theory sticks its neck out and shows ways it could be proven false through experiment. This is something that Freudian psychoanalysis, for example, doesn't do since any result found in it can explain away any observable. Such concepts never leave themselves exposed to the possibility of being falsified and hence are not scientific ideas.
    Popper also defends his frequentist theory of probability against more subjective versions of probability. The book seems to have been superseded by more recent philosophy but that is only because we stand on Popper's shoulders.

  8. Alatea Alatea says:

    If only I was clever enough to understand anything...

  9. Otto Lehto Otto Lehto says:

    His reputation preceding him, with a pretty good idea of what the main arguments of the book are, it is a daunting task to read Popper in the original. But it soon becomes clear that there is enough value, ingenuity and originality in The Logic to merit reading the original book in lieu of, or in addition to, later clarifications, commentaries and critiques (including some by Popper himself).

    First, a warning. The logical complexity and mathematical sophistication of his arguments, combined with the author's engagement with the partially outmoded terminology of the positivists and probability theorists, means that some sections of the book will almost certainly appear, to all but the most savant of savants, varying degrees of impenetrable, inscrutable and unreadable. The dense appendices, full of logical and mathematical proofs, can happily be skipped. It is also clear that some parts of the main text of the book have become severely outdated, especially the sections on quantum mechanics (cf. the Heisenberg-Bohr interpretation and its implications). The low point of the book, from a readability perspective, namely the 70 dense pages devoted to probability theory, especially that of J.M. Keynes, and refuting its implications for science, seem to be of little interest to contemporary debates, and only marginally relevant to Popper's main arguments.

    So I would not fuss about reading every chapter, footnote or appendix. The main gist of the book can be expressed in non-technical terms. And Popper himself does a wonderful job explaining his position in the few opening chapters. So it might even be enough to read through chapters I-VI.

    At his best, Popper is a very lucid philosopher of science, whose revolutionary doctrine, that scientific doctrines can never be verified or deemed true, but only temporarily more or less corroborated, is carefully argued for, using a combination of natural language and technical terminology (which is sometimes helpful, although never absolutely necessary, or so it seems to me). The fact that he spends considerable time attacking his contemporaries - the inductionists, the positivists, the Vienna Circle, the pragmatists, the conventionalists, etc. - means that he occasionally gets bogged down in technical minutiae, but the main thread is luckily never lost.

    Disentangling the the fact that he revolutionized the history of the philosophy of science from the particular arguments advanced in the book is a difficult task. As Popper himself always emphasized, there are no isolated observations that are theory-free, but we are always carrying with us some metaphysical assumptions (strictly speaking untestable, unscientific and unempirical). Thus, before reading the book, the reader will almost certainly have been introduced to Popperian methodology via some circuitous route, e.g. a commentary, a philosophy course, or a later critique. These form a king of background halo through which the reading experience will be refracted.

    Some of the baggage that I personally brought to the reading experience - in additional to a deep respect for Popper's critique of inductive science - was the importance and value of some of the criticism that has been targeted against him. This is no time to go through the theories of Kuhn or Feyerabend, for example, but I'm sure the reader will find the time to go read those authors. The fact that Popper has influenced subsequent scholarship is vital to understanding him. It WILL colour the reading experience, but not in the sense of tainting the pure original picture, but motivating the reading experience with a combination of prejudiced respect and curiosity.

    However, I wish to offer one major criticism that I have with Popper's wonderfully stringent theory: I worry that Popper offers too much of an idealized version of science. He proceeds logically to devise an ideal system that bears little resemblance to actual science. More concretely, Popper's system (if we can call it that) contains a realist component and an idealist component, and these two aspects do not mix easily. In fact, they are often in dire conflict with each other.

    The realist component, which I admire, is embedded in his notion of how hypotheses and theories come about. The idealist component, which I see as the problem, is embedded in his notion of how hypotheses and theories are supposed to be put into the test (ideally of the potentially falsifying crucial experiment). Overall, Popper's view of science describes an ideal scientific practice, whereby theories - motivated by WHATEVER source, be it rational belief or irrational flight of fancy - are devised, and crafted, in such a way that they meet the maximum criteria of universality, simplicity and testability (i.e. falsifiability). This is certainly a difficult task, but Popper insists on it. In this view, doing anything else - i.e. devising ad hoc explanations to explain weakness, or devising metaphysical tautologies to explain strengths - is frowned upon, and the practice of science is hopefully purified of such bad methodologies. But we have a problem, since there is no guarantee that the scientists, who are psychologically very much invested and often in love with their own theories, will, absent strong institutional incentives, be motivated to design their theories in such a manner. This assumes too rosy a picture of humanity. In his Open Society and its Enemies, Popper has accused social scientists of being naively optimistic. But in the Logic, Popper seems to fall for the same fallacious view of human motivation and capabilities. Even if Popper acknowledges his logical focus, he SEEMS to be implying that devising such a system of science, where fallibility and falsifiability are crowned king and queen, is theoretically possible.

    But human beings have a psychology that is fighting hard against such devises. Scientists, like other humans, will carry their irrational and self-serving practices, which motivate their quest for knowledge, and their desire to build metaphysical systems, all the way to the experimental stage; and only a strong community of peer pressure and external criticism can build sufficient safeguards against building theories that are impervious to refutation, or, which comes to the same thing, of being reluctant to accept studies that threaten one's cherished theories. Whether such strong institutional studies can be built is an empirical question; even if Popper provides a good way for an ideal scientific community to be structured, it is dubious whether it ever will be. A more reasonable assumption is to assume that science will, hopefully, come to approximate a system of perfect competition, where systems (theories, hypotheses) can be freely tested. Even if most scientists will be reluctant to set their theories to the test, peer pressure can, ideally, force it on them. This seems to me to be the only way to rescue Popper's methodology from the pitfalls of human self-deception.

    And indeed, Popper knew this: he references natural selection and freedom as prerequisites of science, since they foster competition that can lead to the rejection of bad habits and theories. Indeed, Popper's insistence on falsifiability ONLY makes sense if embedded into this context. But such a context does not preclude pragmatic, instrumental or positivistic theories, either, which seems to make Popper's insistence on a particular methodological commitment metaphysical (which he readily admits); and, more dangerously, superfluous, if RESULTS are what matter. (And results can be obtained using probabilistic logic, positivistic induction, or any other methodology.)

    Even if Popper's original formulation of scientific practice can be criticized, and has been with justification, this is partly missing the point. The value of Popper's insight is that even though it contains many outdated and outmoded paragraphs, it opened up a whole new methodology. Very few thinkers have been able to set up a new paradigm that challenges the very foundations of our commonly held beliefs and practices, but Popper certainly did, and he did so with rigorous logic.

    Great thinkers are often ones who use reason AGAINST reason, use logic AGAINST logic, i.e. to show the limits of reason and logic, and this is exactly the greatest contribution of Popper's critical method. He does not leave us with debilitating skepticism, but with exhilarating awareness of the imperfections of our knowledge, the constantly challenging nature of reality, the critical nature of science, and the irrational rationality of our own drives, beliefs, faith and curiosity.