Angèle Kremer Marietti


In this commentary, I will strictly follow (through sections 1-13, some of whose titles are grouped) the arguments of Hans-Joachim Niemann, professor of philosophy at Bamberg University (Germany), who himself – in an article entitled "The Crisis of Epistemology : Sokal, Bricmont and Scientific Standards in Philosophy" (Conceptus XXXII 1999) [1] – answers various critical remarks on Popper' s epistemology made by Alan Sokal, professor of physics at the University of New York, and Jean Bricmont, professor of theoretical physics at the Catholic University of Louvain, in their book entitled Impostures intellectuelles.


Professor Niemann first approves of the Sokal-Bricmont strictures on the fashionable French writers they quote in their book [2], a work whose aim may rightly be considered as exposing the spreading relativism in Europe and the United States. Accordingly, Sokal and Bricmont' s remarks above all concern the neglectful, incompetent and/or dishonest treatment of science in general by some "postmodern thinkers".

Sokal and Bricmont also mean to explain the spreading of epistemological relativism. Niemann believes that they do not achieve this through a rational reconstitution of the relevant thinkers' trend, in particular their wish to serve tolerance against the belief in absolute truths. Let us note that, to Niemann the opposite of epistemological relativism is the belief in the existence of absolute truths. Now we know that the idea of an absolute concerning method or applied to truth is no character of contemporary sciences, nor consequently the epistemology of Sokal and Bricmont who are no upholders of absolute truth, though certain epistemologists may think so !

Thus, to Niemann, Sokal and Bricmnt wish to explain modern or postmodern relativism historically. Therefore they reach what Niemann calls a "surprising result", which he means to analyze in his article. For relativism, as reflected in the indicted postmodernists' work, supposedly rose, according to Sokal and Bricmont from a reaction to the ambiguity and inaccuracies in Popper's main work (Conceptus p.3) :

"Of course, Popper is not a relativist, quite the contrary. He is nevertheless a good staring point, first of all because many of the modern developments in epistemology (Kuhn, Feyerabend) arose in reaction to him, and secondly because, while we disagree strongly with some of the conclusions reached by Popper's critics such as Feyerabend, it is nevertheless true that a significant part of our problems can be traced to ambiguities or inadequacies in Popper's The Logic of Scientific Discovery." [3]

Popper's defects, together with his refusal to acknowledge the possibility of an infallible science, have resulted in a "crisis of epistemology", because the numerous structures on his work would have given birth to an irrationalist trend. According to Niemann, these reproaches arise >from a now already thirty-year old mistake in interpretation, which Popper refuted in his own time. To this distorted image (in Niemann's eyes) of Popper's epistemology would be added, according to him, a spurious genealogy of postmodernism together with an unsuccessful strategy – which would show that Sokal and Bricmont, who acknowledge "scientific standards" as evident in natural sciences, consider them as superfluous when philosophy is concerned.

Now we must note this particular point – a basic one to him, it seems – in Niemann's reaction : this notion of "scientific standards", a hardly explicit one in natural sciences to begin with. Does it refer to general rules of procedure, to a certain methodical canon, or to a particular working mode ? Indeed, why should these not exist? But one may wonder at the strange idea of introducing "scientific standards" in philosophy : what would they stand for ? Would it mean for instance that one should not reconsider what was once refuted in the history of philosophy ? Would philosophical argumentation be exhausted once and for all ? Or again could a so-called "mistake in interpretation" about a philosophical doctrine be avoided if "scientific standards" were strictly observed ? Above all, this notion which Professor Niemann seems to value particularly is far from being clearly defined in natural sciences, and in any case, is far from obvious to scientists. Does it finally depend on ethics or epistemology ? Anyhow, it should itself require a full development.

This expression should have been more precisely defined, and in particular, its explicit determinations should have been stated. In the way it is used, it might only mean "a code of right proceedings", which no one would refuse provided its precise rules are known.

1. Popper's mistakes and their consequences

Niemann acknowledges the obvious relationship between Kuhn and Feyerabend and postmodern relativism, and he thinks it has been made possible in the process of time. Long before Lyotard, Kuhn and Feyerabend questioned the capacity of science to select theories according to objective criteria, and therefore to doubt its own capacity to reach true knowledge. To Kuhn, the uncertainty of alternative theories might derive from their incompatibility ; to Feyerabend, science would be nothing but a myth; finally, to Lyotard, it would be nothing more than one "narration" among others. So there is no reason why we should not consider Kuhn and Feyerabend as the fathers of contemporary postmodern thought, as Sokal and Bricmont explicitly do.

As to perceiving Popper as, so to speak, the grandfather of all modern relativists because he supposedly led Kuhn and Feyerabend on the wrong way, and consequently gave rise to relativist thought during the last decade, that Niemann finds "curious" for various reasons he expounds as follows :
1) Popper would have criticized relativism in a 1961 Appendix [4], then declaring that intellectual and moral relativism was the century's philosophical disease;
2) his philosophy would precisely be a remedy to this disease. Accordingly, Niemann demurs at this reproach which puts Popper on a level with postmodern thinkers.

Besides, to my mind, I may add that Popper was explicitly against the Sociology of knowledge in 1945 (see The Open Society and Its Enemies, chapter 23). Anyway, in fact, Popper is thus found however in the relativist or postmodern companionship with Kuhn, Feyerabend, Lacan, Kristeva, Irigaray, Latour, Lyotard, Baudrillard, Deleuze, Guattari et Virilio, since he is charged with having – even indirectly – caused postmodern relativism.

Sokal and Bricmont also blame him for using unintelligible language; and undoubtedly, the wrong interpretation of his works proceeds, they think, from his bewilderingly unclear expression. On this point, Niemann asks how far a "scientist" may be deemed responsible for having been misunderstood, unless he has deliberately used obscure language. As regards unintelligible language, his major argument is that Popper has always explicitly disapproved of confused expression ; neither does he allow Sokal and Bricmont to charge Popper with having made a series of epistemological mistakes.

Niemann then selects these two types of charges which, he points out, Sokal and Bricmont fail to justify by any quotation from Popper (Conceptus p.5) : but one must observe that he himself, in his whole article, only provides rare quotations from the master; if however, references to his work are frequent enough on the whole, they are often far from explicit with regard to what they are meant to demonstrate.

Let us first notice that these two arguments are not faultless. Censuring relativism unfortunately would not prevent a philosopher's thought from giving rise to relativism, either directly or through by-paths. Objecting to confused expression does not preserve from confusion either . A philosopher's opposition to obscurity or confusion cannot preserve him from using confused language, or such a complex one as to conceal the real problems. If Popper has not been read as he deserved, should not his defender provide a closer reading of his texts, and a more precise interpretation of his very complex work ?

At this juncture, Niemann thinks that Sokal and Bricmont are mistaking unresolved problems for an unclarified representation. Some of Popper's theses have often been criticized : his falsification method, his criteria of verisimilitude [5], his treatment of induction, or his interest in "world three", the world of objective thought and reason. And Popper has distinguished between the criterion of falsifiability "for the empirical character of a system of statements" and the rules of 'falsification' [6]. According to Niemann, all the critics do not result from the ambiguities or inaccuracies of his philosophy, but only means that the questions he put remain unresolved. Probably so...

Professor Niemann thinks that the wrong reading of Kuhn and Feyerabend is now unquestionable : the postmodernists' faulty reading is obvious, and moreover, he believes, it is shared by Sokal and Bricmont, who unquestioningly accept David Stove's, Larry Laudan's, Hilary Putnam's and W.H. Newton-Smith's versions, all of which he distrusts. As for himself, Niemann chooses to turn to the presentation by David Miller, the distinguished upholder of Popper's critical rationalism, and to refer to the works of another renowned popperian, Hans Albert (Conceptus p.6).

Therefore Popper, who always saw to it that his works were correctly read, might yet have been faultily read, though his texts were the best written possible... And a – wilfully or unwittingly ? – mistaken reading of Popper was for Sokal and Bricmont the means to convince that Popper's defects could have caused the exaggerated censures of Kuhn and Feyerabend, those who would give rise to postmodern thought. Then Kuhn and Feyerabend's relativism was due to a disproportionate reaction to Popper's writings. But did Kuhn and Feyerabend really need a wrong interpretation of Popper to develop their own irrational theories? Were they capable of a rational reaction ? Niemann doubts it (Conceptus p.7).

Regarding the possibly wrong interpretation of Popper's work, it must be said that it would not be the first time in the history of philosophy that a philosopher would be misunderstood, and not by his opponents alone. In any case, a wrong interpretation is not to be countered by the author's supposedly genuine intentions, but by thorough close reading of his texts.

Niemann himself curiously ascribes to Sokal and Bricmont the statement that Popper must have been "stubborn" not to believe that the sun would rise to-morrow. Now "stubborn" appears in their expression "stubborn opponent", with regard to the notion of confirmation [7] : as Sokal and Bricmont wrote, Popper indeed proved a "fierce opponent" to confirmation and in fact did he not replace it by "corroboration", whose function is not confirming ? Popper rather offered examples illustrating rigorous but unsuccessful attempts at refutation.

Another of Niemann's personal interpretations : when Popper substitues falsification for unsure testing, he understands it as a sure falsification in Sokal and Bricmont's conception. As no scientist ever rejects a theory on the first negative experiment, Sokal and Bricmont "must", according to Niemann, think that Popper was mistaken when he imagined a strict falsification. Consequently he questions this possible version of Sokal and Bricmont's thought, which is in fact both his own and erroneous.

2. The postmodern aftermaths of the constraint inherent in method.

Niemann stresses Sokal and Bricmont's charge against the modern epistemologists (those of the Vienna circle, Popper and others) who carried on the "formalization of scientific method". As concerns Popper, Niemann explains, by this attempt at formalization and abstraction he only meant to make scientific method more easily criticizable, emendable and applicable to other areas of human activity. And since they develop the idea that it is impossible to write a Logic of Detective Enquiry, Sokal and Bricmont would ipso facto seem to refuse the very concept of Popper's Logic of Research (Logik der Forschung ) (see Conceptus p.9). In fact Sokal and Bricmont state that codifying scientific research is totally impossible at the present time. And if, particularly, they oppose the formalization of scientific method, it is because they consider as fundamental the empirical proceedings of actual science, which in general philosophers rarely know except by hearsay.

Niemann justifies Popper by explaining that, to him, formalizing does not mean establishing a fixed and determined method, but rather a critical discussion of all the methods in use. According to him, the relationship between Kant and Newton is identically reproduced in that between Popper and Einstein, with Popper even ahead of Kant ! (Conceptus p.10) Let us note, however, that this advance on Kant is less than sure, if one takes into account such texts as Kant's Theory of the Sky, as well as numerous passages from his Criticism of Pure Reason or his First Metaphysical Principles on the Science of Nature, which largely and positively supersede some of Newton's pronouncements [8]. Nothing of the kind can be said regarding the relationship between Popper's philosophy and Einstein's theories.

And Niemann, who clearly and indeed rightly wishes to discriminate between Popper and Feyerabend, nevertheless states that Popper himself, long before Feyerabend, expounded the counterpart of the famous "anything goes". As a proof, he quotes this proposition out of the preface of The Logic of Scientific Discovery, against the language analysts :

"Language analysts regard themselves as practitioners of a method peculiar to philosophy. I think they are wrong, for I believe in the following thesis.
Philosophers are as free as others to use any method in searching for truth. There is no method peculiar to philosophy" [9]

Which means : philosophers are free to use the method they choose – but is this not an opinion common to all philosophers, and alien to Feyerabend's hasty formula ?

Niemann then strangely brings together Feyerabend's epistemology and that of Einstein who boasted of being an "unscrupulous opportunist", contrary to the "systematic epistemologist" who is only intent on defending "his" system against the whole world. Niemann claims that Sokal and Bricmont are drawing the same parallel : do they not reproach Popper, but not Feyerabend, with having given rise to relativism ? (Conceptus p.11) Niemann sticks to it : Popper's critical formalization cannot be charged with having given birth to postmodern relativism.

3. Irrational reactions to Popper's epistemology

Accordingly Niemann comments this passage from Impostures intellectuelles :
"Part of twentieth-century epistemology (the Vienna Circle, Popper, and other) has attempted to formalize the scientific method.
The partial failure of this attempt has le, in some circles, to an attitude of unreasonable skepticism." [10]
This is a text questioning Popper's falsificationism ; to defend him, Niemann claims to refer to unwritten rules of scientific criticism. He himself denounces what he calls fallacious attempts at interpreting Popper literally (Conceptus p.12). Then he turns back to what he calls "scientific standards", which he uses to counter Sokal and Bricmont's arguments. He hardly refers to Stove's (whose book he quotes, Popper and After. Four Modern Irrationalists, Oxford: Pergamon, 1981), Putnam's, Laudan's and Newton-Smith's theses : as if they had been declared void beforehand ! Yet he exceptionally answers one remark by Stove on progress, by stating that Popper meant to "propose methods to increase knowledge and find a criterion validating scientific progress" (Conceptus p.13). This would be meaning well...

However, we must notice that proposing methods both to increase knowledge and to find a criterion validating scientific progress is a hard programme to follow regarding contemporary science, especially if one is no an active specialist in any particular science. It cannot, without ridiculous pretension, be a programme for either an epistemologist or a historian of sciences. Only a specialized scientist can find methods suitable for research in his own subject, and consequently for the pursuit of scientific progress as a whole : for is this not his actual work ? As for the philosopher, no one prevents him from pondering over the scientist's methods, at least those known to him ; in any case, he may not prescribe the methods specialists are to follow in every aspect of their research. Now on the contrary, it seems that Popper wanted to draw up a prescriptive and normative programme for scientific research : he was apparently wandering outside his scope.

4. Should a falsified theory be rejected ?

Whereas he refuses to consider Popper as the forefather of postmodern relativism, but sees Popper as Feyerabend's forerunner, Niemann presents him as announcing Kuhn (Conceptus p.4). In fact, Niemann considers Popper as the one who defined falsification from the reactions of a "scientific community" (Conceptus p.14). Let us note, however, that thinking a scientific community necessarily agrees on the state and contents of its subject does not directly involve justifying the kuhnian concepts of paradigm and incompatibility. Yet, one among Niemann's references might seem to suit this relation, though it describes a normal behaviour :

"For it means that we are stopping at statements about whose acceptance or rejection the various investigators are likely to reach agreement. And if they do not agree, they will simply continue the tests, or else start them all over again" [11].

That is : this amounts to adopting terms which the various scientists may agree to accept or reject. And if they do not, they simply carry on with their tests or start them all over again. Concerning this partial assimilation, see Karl Popper, "Falsificationism versus Conventionalism" (1934) : the introductory materiel to chapter IV (sections 19-22) of The Logic of Scientific Discovery) ; I would quote chapter IV of The Logic of Scientific Discovery treating of falsifiability (section 19), in which Popper criticizes conventionalism by proposing the notion of "scientific crisis" and some remedies for it:

"Whenever the 'classical system' of the day is threatened by the results of new experiments which might be interpreted as falsifications according to my points of view, the system will appear unshaken to the conventionalist. He will explain away the inconsistencies which may have arisen; perhaps by blaming our inadequate mastery of the system. Or he will eliminate them by suggesting ad hoc the adoption of certain auxiliary hypotheses, or perhaps of certain corrections to our measuring instruments. [...]
But the newly rising structure, the boldness of which we admire, is seen by the conventionalist as a monument to the 'total collapse of science', as Dingler puts it." [12]

Particularly, according to Niemann, Popper nowhere wrote what Sokal and Bricmont say about him : "and if the latter (observations or experiments) contradict the predictions, it follows that the theory is false and must be rejected."[13]

Niemann claims that it is not a question of simplifying – because Sokal and Bricmont writes that they give only a summary of Popper's theses [14] – Popper's epistemology, but rather of perverting it ! Such statements, which he considers as erroneous, would have prompted Sokal and Bricmont to discriminate their logical outcome in Kuhn's "incommensurability" and Feyerabend's "anything goes" !

Niemann acknowledges that Popper may have referred to the contradiction between predictions and the empirical basis of a falsification, but he would not have elucidated the logical link between the former and the latter ! Yet we must admit that Popper's proposition quoted by Niemann : "We need not to say that the theory is 'false', but we may say instead that it is contradicted by a certain set of accepted basic statements" [15] indeed results in not validating a theory contradicting facts, since 'basic statements' concern facts. Therefore, without deserving to be called positivists by Niemann, Sokal and Bricmont write about Popper's epistemology : "one can never prove that a theory is false, because, to do that, a single (reliable) observation contradicting the theory suffices" [16].

In fact, Niemann alludes to certain "positivists" and to their belief in the existence of "absolute truths", and he writes : "In any case, whoever thoughtlessly believes in the absolute truth of observations might logically consider that absolutely true empirical data contradicting the theory should lead to a rejection of it. Popper did not offer this conception, but opposed it as no other. That this positivist conception is no longer upheld by anyone should appear as owing mainly to him" (Conceptus p.14). Now Sokal and Bricmont denied being "positivists" at least in that sense, and above all believing in "absolute truths". But Niemann's interpretation is common among some epistemologists who perceive no other alternative; to them, positivists are inclined to absolute beliefs...

As for the second part of the sentence, Niemann goes so far as to answer that Popper always said the reverse (Conceptus p.15). But he should provide convincing quotations. Now, in a general and established way, Popper never stated anything else but this :

1) there exists no true theory;
2) there are falsified theories ;
3) there are not yet falsified theories.

And if Popper does not explicitly declare they are "false", it is obvious that calling theories "falsified" implies that we should no longer wholly trust them.

As to "scientific method", if, following Popper's method, Niemann tries, not indeed to verify but rather to falsify Sokal and Bricmont's expounding of Popper's philosophy, the argument should be more complete, and reveal what, in practise, governs the use of the concepts of "true" and "false" in Popper's texts. Especially, the quotation Niemann puts forward would be more efficient if set in its proper context, for when Popper precisely writes : "We need not to say that the theory is 'false', but we may say instead that it is contradicted by a certain set of accepted basic statements", he openly speaks in a context where the concepts of "true" and "false" – if not excluded from his logic of science since he even states they are not forbidden [17] – can nevertheless be dispensed with. Popper wishes to dispense with them in order not to have to reconsider a truth hailed yesterday but found false to-day :

"The appraisal of a statement as corroborated or as not corroborated is also a logical appraisal and therefore also timeless ; for it asserts that a certain logical relation holds between a theoretical system and some system of accepted basic statements." [18]

With Popper – precisely in the same chapter X of The Logic of Scientific Discovery (section 84) quoted by Niemann – "corroborated" replaces "true", as "falsified" replaces "false", but within different temporal circumstances : for "true" and "false" he declares "non empirical". Popper explicitly writes: "I shall say, even of some singular statements that they are hypothetical, seeing that conclusions may be derived from them (with the help of a theoretical system) such as the falsification of these conclusions may falsify the singular statements in question."[19]. And this is explicitly to be found in a passage close to another one quoted by Niemann elsewhere (loc. cit. chap.III, section 18).

If, finally, as it seems, "falsification" possesses no discriminating sense, and if "false" is a seldom used word, then what does Popper's epistemology mean from the strict point of view of scientific research ? And especially, a more important question may be raised : why should we deal with "falsification" if there is never any legitimate previous testing ?

5. Sure verification, unsure falsification ?

Moreover, Niemann refers to Sokal and Bricmont's statement : "by abandoning verification, one pays too high a price ; and one fails to obtain what is promised, because falsification is much less certain than it seems."[20]

Obviously, Sokal and Bricmont think of verification and falsification, not from the philosophical point of view characterizing Popper's systematic area – actually outside scientific research proper – but indeed in the prospect of the positive results generally desired in any scientific research. Let us note that this does not exactly mean they think Popper spoke of "sure falsification" but, on the contrary, it reveals that with a view to a method of research, falsification may be found less sure than verification, that is, briefly, less fruitful, especially if it represents nothing really crucial from the heuristic point of view.

Therefore, even if Niemann points out that Popper did not immediately imagine a sure falsification (Conceptus p.16, n.57), nevertheless, from Popper's standpoint, the dividing criterion between a scientific hypothesis and a pseudo-hypothesis in fact lies in refutability and so in falsification, and neither in verifiability nor in confirmability. Now, one should notice that an essential condition was underrated by popperians : for it happens that the criterion of refutability demands that scientific theories should be axiomatized – which is far from being universal. Besides, popperians have neglected another important fact ; contemporary physics formulates scientific hypotheses as statistical terms or statements of probability, a terminology regarding which Popper's refutationism is wholly inefficient.

Niemann's argumentation also refers to some traits of Popper's doctrine that contradict his best-known theses : a 1930 text quoted by Niemann states that "...wissenschaftliche Theorien nicht verifizierbare Systeme darstellen"; aber sie sind nicht nur nicht verifizierbar, sondern sie sind auch nicht falsifizierbar" (Conceptus p.16). To be short, scientific theories are not 'nonverifiable' and 'nonfalsifiable'. Popper, Niemann explains, meant that theories are "not absolutely falsifiable", but does this not also mean that they are "not absolutely verifiable", since the proposition contains "verifiable" as well as "falsifiable" ? As late as the English translation of his major book, Popper writes that there cannot be any final refutation of a theory (Conceptus p. 17) [21]. One may then question the heuristic advantage of recommanding refutations rather than confirmations, since refutations do not make it easier to draw secure plans for the progress of knowledge.

6. Sure falsification does not work
7. Falsification is much more complex

Niemann, as an example, quotes Popper writing about himself in 1989: "Popper has immer wieder betont ... daβ...auch die besten empirisch-wissenschaftlichen Theorien nicht als falsch erweisbar sind" : that is " Popper always stated... that... the best theories of empirical sciences cannot be proved false" (Conceptus p.18). Let us remark that Popper precisely writes "the best theories", which must normally be hoped not to be false... But we might also ask a first and fundamental question, almost metaphysical : how have they been received as "the best", since neither pure verification nor "sure falsification" exist, and consequently cannot work anyway ?

Moreover, after having written: "falsification is much less certain than it seems"(22], Sokal and Bricmont write: "falsification is much more complicated than it seems" [23]. Thence Niemann's commentary repeating after Sokal and Bricmont that a theory does not present itself alone to falsification : it is always associated with a large number of subsidiary conditions and auxiliary hypotheses (Conceptus p.19). Now a problem arises : which theories or propositions are to be rejected ? This is also what Niemann asks.

As Sokal and Bricmont justly write, "scientific propositions cannot be falsified one by one, because to deduce from them any empirical proposition whatsoever, it is necessary to make numerous additional assumptions, if only on the way measuring devices work; moreover, these hypotheses are often implicit "[24]. It is true ; and I think that is probably why Popper referred to "levels of universality", and "degrees of accuracy". As concerns levels of universality and degrees of accuracy [25], Popper also provided a solution consisting in drawing the least universal and accurate statement from the most universal and most accurate one. Here again, we must notice how lucky we are to find statements that were already recognized as the most accurate and universal, when believing with Popper that this result would and will never be due to a falsification !

Niemann's position steadily shows that Popper's epistemology is so complex that it eludes the main stricture he refuses, namely that Popper's failures are among the most efficient causes in the genealogy of postmodernism...

8. Theories cannot be controlled separately
9. Science can live with falsified theories.

That theories are not "falsifiable one by one" as Sokal and Bricmont write, Quine best demonstrated through his holism, as Niemann remarks (Conceptus p.20). In any case, Sokal and Bricmont find some formulations of Quine's thought more convenient than others because they are less radical as this one : "empirical content is shared by the statements of sciences in clusters and cannot for the most part be sorted out among them. Practically, the relevant cluster is indeed the whole of science." [26] Now, Niemann reminds us, thirty-seven years before Sokal and Bricmont, Popper had already dealt with Quine's thesis, and also answered just as they did, sixty-five years before them (Conceptus p.21) : see Popper's chapter "Truth, Rationality, and the Growth of Scientific Knowledge" (1940-1962), prepared as a paper to be read at the First International Congress for Logic, Methodology and Philosophy of Science (1960), now chapter 10 of Conjectures and Refutations.

So, though theories may be falsified, it does not follow that they should be systematically rejected, even if the popperian deeply wishes so. This is what Niemann fully states : "A popperian could live with falsified theories; but he generally does not wish so" (Conceptus p.22). At least such must be the case, Niemann explains, as long as no other alternative theory appears. If this happened, the popperian – I suggest – would join the genuine scientist who endeavours to verify rather than "falsify", or at least only "falsifies" as a way to finally verify; but we know that verifying is not the popperian's purpose;

Sokal and Bricmont for example allude to a difficult point such as the orbit of Mercury "falsifying" Newton's theory, though the latter is held valid in spite of obvious "falsification" : "if one takes into account the context, one may very well maintain that is rational to proceed in this way, at least for a certain period of time – otherwise science would be impossible." [27] In order to obviate such drawbacks and save the endangered hypotheses, Popper had offered remedies : he suggested considering the whole system (was he trying to foresee any kind of scientific crisis or revolution ?) or even using ad hoc hypotheses (which scientists avoid as much as possible). This is precisely, Niemann reminds us, what The Logic of Scientific Discovery teaches. Therefore, he concludes, there can exist neither ambiguities nor inaccuracies in that work. However, one question will arise and not the least : where does the falsification theory begin and, above all, where does it end ? And especially, what exactly is the use of it ?

10. Coming near the truth thanks to unexpected verifications
11. The likelier truth there is, the greater verisimilitude

About "unexpected verifications" (Conceptus p.23) Niemann quotes Sokal and Bricmont :

"Besides, the history of science teaches us that scientific theories come to be accepted above all because of their successes. For example, on the basis, of Newtonian mechanics, physicists have been able to deduce a great number of both astronomical and terrestrial motions, in excellent agreement with observations. Moreover, the credibility of Newtonan mechanics was reinforced by correct predictions such as the return of Halley's comet in 1759 and by spectacular discoveries such as finding Neptune in 1846 where Le Verrier and Adams predicted it should be." [28]

Niemann comments this as follows : Popper would not receive as a successful verification the prediction of Neptune through Newton's theory and its actual discovery. For Popper considered the prediction of a phenomenon he thought totally "unlikely", not as a verification, but really as a strict falsification test !

Let us remember, however, that Popper, especially in The Poverty of Historicism (1957), distinguished between prediction and prophecy, the former being made in conditional terms, i. e. based on initial conditions, the latter being the categorical expression of a surmise. When knowing the conditions of the predictions referred to here (calculation and observation) is it reasonably possible to mistake either the prediction of a return of Halley's comet, or the existence of Neptune – calculated by John Couch Adams and Urbain Le Verrier, and observed by Johann Galle – for a mere prophecy ? Indeed not.

Or again, can we say that the confirmation of Newton's theory is due to an "unexpected" verification, while Newton's theory is the source of calculations supported by observations, both of which allow to foretell events providing its verification ? The realized prediction here offers the obvious validating experiment of the theory. Popper identifies the "unexpected" character of an occurrence with the knowledge of a "slight probability" [29]. But can the unexpected or the unlikely be put forward as concerns the discovery of Neptune ? If so, we should extend these notions to the whole knowledge mankind has gradually acquired from its initial ignorance onwards : for any new knowledge, from this point of view, is unexpected or unlikely if compared to initial ignorance, but it is no longer so if we consider it in relation with the efforts which allowed it to be reached, i. e. calculations and observations.

It is strange that we should denounce as "improbable" the observed fact of a hitherto unobserved planet being discovered in the very place where some calculations (those of Le Verrier and Adams) [30] located it ! Now, this is precisely what Popper did, at the same time calling "wonderful corroboration" of Newton's theory the predictions leading to the discovery of Neptune, merely because they concerned an "excessive improbability" ! Here again, "improbability" does not refer to a mathematical theory of probability, but to anyone's psychological state of ignorance previous to any knowledge.

All things considered, instead of an induction, Niemann shares Popper's view on the signs of verisimilitude (Conceptus p.24), a concept connected with the comparison between theories (Conceptus pp.25-26). For he then refers to that other planet issue which opposed Newton's and Einstein's theories : the question of the orbit of Mercury (Conceptus p.24], about which Sokal and Bricmont write "We have not, however, reached the end of our troubles. If one takes the falsificationist doctrine literally, one should declare that Newtonian mechanics was falsified already in he mid-nineteenth century by the aniomalous behavioer of Mercury's orbit." [31]. The anomaly was later explained (in 1915) "as a consequence of Einstein's general theory of relativity" [32].

In Popper's language, on the one hand, Newton's theory is "corroborated" by the existence of Neptune; on the other hand, it proves "falsified" by the orbit of Mercury which corroborates Einstein's theory. To Niemann, this "contradiction" should for ever remove any theoretical temptation to refer to induction. He especially stresses the fact that the discovery of Neptune can in no way fall into the category of induction, because – among other reasons – of the underdetermination of theories by facts (Conceptus p.25).

Sokal and Bricmont confirm this underdetermination : "there is always a large (even infinite) number of theories compatible with the data – and this, whatever the data and whatever their number"[33]. According to Niemann, Popper had already foreseen (in 1930-33) [34] this underdetermination formulated by the Duhem-Quine thesis ! To meet this problem, Sokal and Bricmont suggest to compare theory with empirical proofs :

1) by relying on such strong arguments in favour of a theory that questioning it would be unreasonable ;
2) or by supposing that a hitherto unknown valid theory is still possible, so that the existing theory only possesses a "rather low subjective probability" [35] ;
3) or by finding that there exists not "a single plausible theory that accounts for all existing data" [36].

12. The "new induction method"

Niemann wonders at the scientists' wish to formulate the relation between data and theory ; yet this relation is an elementary operation, apparently necessary to classical epistemology. As if ironically, he stresses that theory can have "become more probable at least subjectively", according to his interpretation of Sokal and Bricmont, who more precisely write :

"The first difficulty concerns the status of scientific induction. When a theory successfully withstands an attempt at falsification, a scientist will, quite naturally, consider the theory to be partially confirmed and will accord it a greater likehood or a higher subjective probability."[37]

Is this not the usual scientific method – seemingly unknown to popperian philosophers ? But undoubtedly the status of popperian truth is such that any agreement must be "unexpected" (see "unerwartete Zusammenpassen", Conceptus p. 26 )!

Fortunately, Sokal and Bricmont are obviously not the only ones who fail to understand the popperian concept of corroboration (Conceptus p.26). The two physicists write :

"Note that Popper calls a theory "corroborated" whenever it successfully passes falsification tests. But the meaning of this word is unclear; it cannot just be a synonym of "confirmed", for otherwise the entire Popperian critique of induction would be empty. See Putnam (1974) [38] for a more detailed discussion." [39]

Therefore Niemann, referring to chap. X of The Logic of Scientific Discovery, reminds us that "a hypothesis is corroborated when it has stood the trial of tests" (Conceptus p. 27). In that chapter, Popper expounds the relations of compatibility and incompatibility that can be established by corroboration :

"We regard incompatibility as falsification of the theory. But incompatibility alone must not make us attribute to the theory a positive degree of corroboration: the mere fact that a theory has not yet been falsified can obviously not be regarded as sufficient. For nothing is easier than to construct any number of theoretical systems which are compatible with any given system of accepted basic statements." [40]

What we can understand is that non-falsifiability is not enough to make a theory receivable ; but as nothing allows to confirm the latter, there is no way to see how science could ever take shape : the popperian solution is definitely unsatisfactory to scientists. Niemann notes that the example of induction provided by Sokal and Bricmont bears on applied science, when they refer to physicians and engineers [41], so he concludes that Sokal and Bricmont are confusing science with technique ! He even maintains that he cannot find any induction theory in Sokal and Bricmont : and yet he must have read statements of theirs that can situate and solve the problem :

"Historians, detectives, and plumbers – indeed all human beings – use he same basic methods of induction, deduction, and assessment of evidence as do physicists or biochemists."[42]
"The absence of any "absolutist" criteria of rationality, independent of all circumstances, implies also there is no general justification of the principle of induction (another problem going back to Hume). Quite simply, some inductions are justified and others are not; or, to be more precise, some inductions are more reasonable and others are less so." [43]
"Obviously, every induction is an inference from the observed to the unobserved, and no such inference can be justified using solely deductive logic." [44]

Now Popper gave his preference to deduction over induction. Niemann, for his part, draws his conclusion by pointing out that the "new induction theory" consists in asserting that " a few conclusions are justified and others are not" (Conceptus p.29] !

13. Scientific standards

Niemann's article ends with a catalogue of the various "scientific standards". There are eighteen of them, which mainly concern methods in hermeneutics. But which hermeneutics ? Obviously all these propositions would deserve to be examined separately, yet in relation with one question : to what purpose ? On the one hand, is the aim discovery or justification ? On the other hand, is the aim ethics or epistemology ?

In fact, apparently, the various principles are referred to, now for one reason, now for another ; these principles concern precision, foundation, convenience or proportionality. The same is true regarding rules of circumspection, objectivity, empiricism, proof, intelligibility or competence. These principles and rules I do not think Sokal and Bricmont have ever infringed, even if they are charged with not having backed up the adversary's weak argument on occasion !

Université d'Amiens

Thanks to Eliane Cuvelier for the English translation


1) "Die Krise in der Erkenntnistheorie'. Sokal, Bricmont und die wissenschaftlichen Standards in der Philosophie „ (Conceptus, XXXII 1999, Nr.80, 1-35).
2) Alan Sokal, Jean Bricmont, Impostures intellectuelles, Paris : Odile Jacob, 1997 ; Paris, Le Livre de Poche, 1999.  Hans-Joachim Niemann quotes the American Edition: Fashionable Nonsense : Intellectuals' Abuse of Science; New York : Picador, USA, 1998. There is another English translation : Intellectual Impostures: Postmodern Philosophers' Abuses of Science, London : Profile Books, 1998. And a German translation : Eleganter Unsinn – Wie die Denker der Postmoderne die Wissenschaften missbrauchen, München : C.H. Beck, 1999.
3) Fashionable Nonsense, p. 61.
4) See the 1961 edition of The Open Society and its Enemies (1945). 12th Ed., London : Routledge and Kegan Paul, 1977.
(5) 'Verisimilitude' : " The extent to which a hypothesis approaches the truth. The first approach to the notion, due to Popper, identifies this with the extent to which a theory captures the whole truth: a theory T will have more verisimilitude than a rival T just in case T implies more truths and fewer falsities than T. But the formal development of the notion has proved extremely tricky, especially as the verisimilitude of theories is apt to vary with variations in the language in which they are couched."(Oxford Dictionary of Philosophy, 1940).
6) See Karl Popper, "Falsificationism versus Conventionlism" (1934) : the introductory materiel to chapter IV (setions 19-22) of The Logic of Scientific Discovery.
7) Fashionable Nonsense, p. 63.
8) I think I have proven it in : Angèle Kremer Marietti, Philosophie des sciences de la nature, Paris, PUF, 1999 ; see pp. 118-124, 243-257.
9 Karl Popper, The Logic of Scientific Discovery (1935), London and New York : Routledge, 1999, Preface to the First English Edition (1959), p. 15.
10) Fashionable Nonsense, p. 60.
11) Karl Popper, The Logic of Scientific Discovery, ch. V, 29, p.104.
12) The Logic of Scientific Discovery, ch. IV, 19, p. 80.
13) Fashionable Nonsense, p. 62.
14) Fashionable Nonsense, p.62, note 65 : «In this brief summary, we have, of course, grossly oversimplified Popper's epistemology [...] However, nothing in the subsequent discussion will be affected by these simplifications ». 
15) Karl Popper, The Logic of Scientific Discovery, ch. X, 84, p. 274.
16) Fashionable Nonsense, p. 62.
17) The Logic of Scientific Discovery, ch. X, 84, p. 274 : « This certainly does not mean that we are forbidden to use the concepts 'true' and 'false', or that their use creates and particular difficulty. »
18) The Logic of Scientific Discovery, ch. X, 84, p. 275.
19) The Logic of Scientific Discovery, ch. III, 18, p.75-76.
20) Fashionable Nonsense, p. 62.
21) Niemann quotes, in The Logic of Scientific Discovery, London, Hutchinson, 1959, the Index : 'Disproof': "No conclusive disproof of a theory can be produced"; see the same idea : K Popper, Die beiden Grundprobleme der Erkenntnistheorie (1930-33), Tübingen, Mohr-Siebeck, p. 354.
22) Fashionable Nonsense, p. 62.
23) Fashionable Nonsense, p. 64.
24) Fashionable Nonsense, p 65.
25) The Logic of Scientific Discovery, ch. VI, 36, p. 123.
26) Fashionable Nonsense, p.66, note 74.
27) Fashionable Nonsense, p. 67.
28) Fashionable Nonsense, p. 63-64.
29) See Karl Popper, Realism and the Aim of Science [1956], Edited by W.W. Bartley, III, Totowa, NJ : Rowman and Littlefield, 1983, p. 238.
30) Realism and the Aim of Science, p. 247.
31) Fashionable Nonsense, p. 67.
32) Fashionable Nonsense, p. 67, note 76.
33) Fashionable Nonsense, p. 69.
34) Quoted by Niemann ; see Karl Popper, Die beiden Grundprobleme der Erkenntnistheorie.
35) Fashionable Nonsense, p.71.
36) Fashionable Nonsense, p.71.
37) Fashionable Nonsense, p.62.
38) Hilary Putnam, "The 'corroboration' of theories", in The Philosophy of Karl Popper, vol.1 ; see Paul A. Schilpp, LaSalle, Illinois, USA, Open Court Publishing Company, p. 221-240.
39) Fashionable Nonsense, p. 63, note 66.
40) Karl Popper, The Logic of Scientific Discovery, ch. X, 82, p. 266.
41) Fashionable Nonsense, p.63.
42) Fashionable Nonsense, p.56.
43) Fashionable Nonsense, p.59.
44) Fashionable Nonsense, p.63.

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