Popper's account of refutation is the linchpin of his famous view that the method of science is the method of conjecture and refutation. This thesis critically examines his account of refutation, and in particular the practice he deprecates as avoiding a refutation. I try to explain how he comes to hold the views that he does about these matters; how he seeks to make them plausible; how he has influenced others to accept his mistakes, and how some of the ideas (...) or responses to Popper of such people are thus similarly mistaken. I draw some distinctions necessary to the provision of an adequate account of the so-called practice of avoiding a refutation, and try to rid the debate about this practice of at least one red herring. I analyse one case of 'avoiding' a refutation in detail to show how the rationality of scientific practice eludes both Popper and many of his commentators. Popper's skepticism about contingent knowledge prevents him from providing an acceptable account of contingent refutation, and so his method is really the method of conjecture and conjecture. He cannot do without the concepts of knowledge and refutation, however, if his account of science is to be plausible or persuasive, and so he equivocates between, amongst other things, refutation as disproof and refutation as the weaker notion of discorroboration. I criticise David Stove's account of this matter, in particular to show how he misses this point. An additional advantage Popper would secure from this equivocation is that if refutations were mere discorroborations they would be easier to achieve, and hence more common in science, than is the case. On Popper's weak notion of refutation, it would be possible to refute true theories since corroboration does not entail truth. There are two other related doctrines Popper holds about refutation which, if accepted, make some refutations seem easier to obtain than is the case. I call these doctrines 'Strong Popperian Falsificationism' (SPF) and 'Weak Popperian Falsificationism' (WPF). SPF is the false doctrine that if a prediction from some theory is refuted then that theory is refuted. Popper does not always endorse SPF. In particular, when confronted with a counterexample to it, he retreats to WPF, which is the false doctrine that if a prediction from some theory is refuted then that theory is prima facie refuted. WPF , or even SPF, can seem plausible if one has in mind predictions derived from theories in strong or conclusive tests of those theories, which I suggest Popper characteristically does. v Popper is disposed to describe any such case of predictive failure which does not lead to the refutation of the theory concerned as one in which that refutation has been avoided. To reinforce his portrayal of the refutation, or the attempted refutation, of major scientific theories as the rational core of scientific practice, Popper treats the so-called practice of avoiding a refutation as untypical of science, and much so-called avoidance he dismisses as unscientific or pseudo-scientific. I argue that his notion of avoiding a refutation is incoherent. Popper is further driven to believe that such avoidance is possible, however, because he conflates sentences with propositions and propositions with propositional beliefs. Also, he wishes to avoid being saddled with the relativisim that is a consequence of his weak account of refutation as discorroboration. Popper believes that ad hoc hypotheses are the most important of the unscientific means of avoiding a refutation. I argue that his account of such hypotheses is also incoherent, and that several hypotheses thought to be ad hoc in his sense are not. Such hypotheses appear to be so largely because of Popper's use of rhetoric and partly because these hypotheses are unacceptable for other reasons. I conclude that to know that a hypothesis is ad hoc in Popper's sense does not illuminate scientific practice. Popper has also attempted to explicate ad hocness in terms of some undesirable, or allegedly undesirable, properties of hypotheses or the explanations they would provide. The first such property is circularity, which is undesirable; the second such property is reduction in empirical content, which is not. In the former case I argue that non-circularity is clearly preferable to non-ad hocness as a criterion for a satisfactory explanation or explanans, as the case may be, and in the latter case that Popper is barking up the wrong tree. Some cases of so-called avoidance are obviously not unscientific. The discovery of Neptune from a prediction based on the reasonable belief that there were residual perturbations in the motion of Uranus is an important case in point, and one that is much discussed in the literature. The manifest failure of astronomers to account for Uranus's motion did not lead to the refutation of Newton's law of gravitiation, yet significant scientific progress obviously did result. Retreating to WPF, Popper claims that Newton's law was prima facie refuted. In general, astronomers have never shared this view, and they are correct in not doing so. I argue that the law of gravitation would have been prima facie refuted only if there had been good reason at the time to believe as false what is true, namely, that an unknown trans-Uranian planet was the cause of those Uranian residuals. Knowledge of the trans-Uranian region was then so slight that it was merely a convenient assumption, one which there was little reason to believe was false, that the known influences on Uranus's motion were the only such influences. I conclude that in believing vi or supposing that it was this assumption that was false, rather than the law of gravitation, Leverrier and Adams, the co-predictors of Neptune, were acting rationally and intelligently. Popper's commentators offer a variety of accounts of the alleged practice of avoiding a refutation, and of this case in particular. I analyse a sample of their accounts to show how common is the acceptance of some of Popper's basic mistakes, even amongst those who claim to reject his falsificationism, and to display the effects on their accounts of this acceptance of his mistakes. Many commentators recognize that anomalies are typically dealt with by changes in the boundary conditions or in other of the auxiliary propositions employed. Where many still go wrong, however, is in retaining the presupposition of WPF which encouraged Popper to hold the contradictory view about anomalies in the first place. Thus Imre Lakatos and others, for example, have developed a 'siege mentality' about major scientific theories; they see them as under continual threat of refutation from anomalies, and so come to believe that dogmatism is essential in science if such theories are to survive as they do. I examine various such doomed attempts to reconcile Popper with the history of science. It is a common failure in this literature to conflate or to fail to see the need to distinguish a belief from a supposition, and an epistemic reason from a pragmatic reason. I argue that only if one does draw these distinctions can one give an adequate account of how anomalies are rationally dealt with in science. The other important strand in Popper's thinking about 'avoidance' of refutation which has seriously misled some of his commentators is his unfounded belief in the dangers of ad hoc hypotheses. I examine the accounts that a sample of such commentators provide of the trans-Uranian planet hypotheses of Leverrier and Adams. These commentators imply or assert what Popper only hints at, namely, that there is something fishy about this hypothesis. I provide a further defence of the rationality of entertaining this hypothesis at the time. I conclude with a few remarks about Popper's dilemma in respect of scientific practice and his long standing emphasis on refutations. (shrink)

This comment on Steven Boer's “Object-Dependent Thoughts” develops two examples: (1) a counterexample to the "axiom of the seamlessness of truth," namely, that there are no propositions, one true and one false, such that knowing the true one requires believing the false one; (2) a story about the first sighting of Neptune, by John Galle on September 23, 1846, that illustrates how one can understand Galle's remark "That is the planet whose position Leverrier calculated" without believing that there is (...) something to which Galle refers. (shrink)

In 1995 Walker & Company published a small book authored by the professional writer Dava Sobel entitled Longitude: The Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. Not only did the book sell exceptionally well; it also spawned a three‐hour film, Longitude, starring Jeremy Irons and Michael Gambon, and a new, lavishly illustrated work, The Illustrated Longitude, by Sobel and Harvard's William J. H. Andrewes. It is difficult to think of another book in the (...) history of science that has attained comparable success. Yet it seems that history of science journals have taken scant notice of the book; my efforts to locate reviews of Sobel's volume in history of science journals have turned up only a single review, that being in Italian. This is all the more distressing because the book and film present a very controversial view of Astronomer Royal Nevil Maskelyne. This is not the place to examine Sobel's recipe for success, but it seems relevant background in reviewing a book also written by a professional journalist, also published by Walker, and fairly comparable in format to Sobel's.The history of science is rich in fascinating stories that could delight a variety of readers. The story of the search for longitude in the eighteenth century is certainly one of these; the dramatic quest to discover Neptune in the mid nineteenth century is another. Put overly briefly, the latter is the story of the frustrated efforts of a young, personally diffident but intellectually bold Cambridge graduate, John Couch Adams, to convince either the director of the Cambridge Observatory or England's Astronomer Royal to look for a planet that Adams's calculations had told him must be located at a specific position. It is also the story of the brilliant and arrogant Urbain J. J. Leverrier, who had independently completed comparable calculations and who beat Adams to the discovery by persuading not one of his French colleagues but an astronomer at the Berlin Observatory to launch a search, which within a few hours had located Neptune. It is also the story of the immense controversy that followed and that has in the last few years been given a new twist with the recovery of key documents carried off to Chile from the Royal Greenwich Observatory.Tom Standage, science correspondent for the Economist and author of The Victorian Internet, has taken up the challenge of retelling the Neptune story, which had previously been treated in dozens of articles and in book‐length studies by John Pringle Nichol, Albert Glodin, Morton Grosser, and Patrick Moore. Moreover, Standage presents the Neptune narrative as the centerpiece in a story that stretches from William Herschel's discovery of Uranus to the discovery of Pluto in 1930 and even to the spectroscopic detection in the last few years of dozens of extra–solar system planets. Standage's clear and engaging prose is based on extensive reading in English and French sources, some manuscript work, and interviews with a number of the discoverers of extra–solar system planets. Although the book is bereft of footnotes, an annotated bibliography at its end partially fulfills their function. Numerous illustrations appear, but these tend to be rather dark and small.Although the book is generally reliable, some significant errors appear. For example, whereas Standage reports that William Herschel did not see Uranus alter in size, Herschel observed its diameter nearly double in the two months after his first observation of it. It is John, not William, Herschel who is buried in Westminster Abbey. Benjamin Peirce's last name is misspelled , as is Christiaan Huygens's first name , and it is incorrect to say that Huygens “considered it was unlikely that there was life elsewhere in the solar system” . Also, because Lowell Observatory director Vesto Slipher played such a major role in the discovery of the planet Pluto by creating and directing the research program that enabled a recent high school graduate, Clyde Tombaugh, to be the first to recognize the planet on a photographic plate, it seems inappropriate that Standage makes no mention of Slipher in recounting the discovery of Pluto.Overall this is a highly engaging story, well told and based on good sources. One would hope that it may follow Longitude into film, at least a documentary, and that other authors and publishers will recognize the market for such exciting stories from the history of science. (shrink)

This book is intended as a reference source of “universal scientific laws, physical principles, viable theories, and testable hypotheses” from ancient times to the present. Robert Krebs states that he includes only the physical and biological sciences, including geology, but in fact there are also several mathematical and logical entries ranging from the Greeks to Gödel. The book contains over four hundred entries, in alphabetical order, averaging less than a page each, plus a glossary of nearly four hundred technical terms. (...) Evidently, it is intended as a library reference for a general audience. It does not seem to be directed toward professional historians of science. The author is a retired university science administrator in the health sciences field.Opening the book at random, I find four entries on the facing pages: “Carnot's Theories of Thermodynamics,” “Caspersson's Theory of Protein Synthesis,” “Cassini's Hypothesis for Size of the Solar System,” and “Cavendish's Theories and Hypothesis.” It is hard to know what the principle of selection is, other than comprehensive coverage. But although it is impressive, the coverage is spotty. The famous story of Adams, Leverrier, and Neptune is not included, for example—perhaps because no new law is involved.To a historical scholar, such a project has obvious pitfalls; I will list some of them. First, it is whiggish in selecting and evaluating the entries from our standpoint and in often omitting now‐discredited content. For example, the entry on Carnot does not mention caloric, although it does mention the model of water flowing over a waterwheel. The book encourages the idea that discoveries and other major results are more or less punctiform, the achievements of particular individuals at particular times. To be fair, in his introduction Krebs does describe science as an ongoing, self‐correcting process in which “laws” sometimes turn out to be false or to need correction. The book is historically uncritical, since it accepts at face value that eponymous results were actually achieved by the person celebrated in the name. The entries are necessarily too brief to indicate much of the wider historical context, or even the technical context, in which the law or theory under discussion was developed. Krebs's statement of his intent, in the introduction to the volume, is theory centered and seems to take physics as a model, although in fact there are many entries from the biomedical sciences that do not neatly fit this model. The author's attempt to characterize his subject matter—scientific laws—is philosophically naïve. Finally, even if we leave aside the difficulty of making complex technical results accessible to a general audience in a very limited space, no single author can be expert enough to maintain a high standard throughout a volume of such scope. Krebs identifies no panel of expert consultants enlisted to check his entries.The entries that I sampled sometimes contained less‐than‐sharp formulations, inaccuracies, and even contradictions. For example, Krebs describes Aristotle, in cliché fashion, as a “philosopher” rather than as a “scientist concerned with observations and evidence” , but two paragraphs later it turns out that Aristotle based his account of spontaneous generation on observations! Krebs says that motion was self‐explanatory for Aristotle because things strive to reach their natural places. The entry on Euler mislabels his work on bodies moving with multiple degrees of freedom as the three‐body problem. Fermat's last theorem is said to remain unsolved, yet Krebs obviously prides himself on being up to date. The entry on Planck is historically inaccurate and physically misleading. And so on.For all that, I found the book rather interesting and useful. No reader leafing through it will fail to find this entry or that intriguing. Since the entries are short and discrete, the book makes good bedtime reading. And, given that the laws, principles, and effects are commonly called by these names, the book can serve as a source of general knowledge—but only as a starting point. Given the uneven quality, caveat lector! (shrink)

I criticize Brian Earp's ‘Some Writing Tips for Philosophy’. Earp's article is useful for someone who wishes to do well in analytic philosophy as currently practised but it also casts doubt on why such analytic philosophy would be of interest to someone who wants to learn something new. In addition to its good tips, Earp's article contains two bad tips which, if followed, will tend to produce a paper that says next to nothing. I list the two faulty tips, show (...) how the practices of great philosophers and scientists contradict them, then set out some contrary good tips for philosophers who aim to write a paper that makes a contribution to our knowledge. (shrink)