Introducing: Two excerpts from Ludwik Fleck’s Genesis and Development of a Scientific Fact (“interpretive” Eng. trans., 1979; original German edn., 1935)

Fleck’s pithy monograph of 1935 is deep, with its detailed case studies in medical history, and yet broadly applicable. His epistemology, building here on an example — the Wassermann reaction and its discovery — from Fleck’s own area of expertise (microbiology), analyzes human thought in terms of historical processes and social interaction and is relevant to all kinds of human experience, not just scientific cognition.

Because of its originality, complexity and German idiolect, Fleck’s Genesis and Development of a Scientific Fact (“interpretive” Eng. trans., 1979; original German-language edn., 1935) is not an easy book to epitomize. I recommend that everyone read the original University of Chicago Press translation (1979; paperback reissue, 1981) in its entirety in order to properly grasp Fleck’s theory of knowledge. Here I wanted to highlight Fleck’s important insights about “the seeing of Gestalts” (Cohen & Schnelle, Introduction, xxi), and have chosen to digitize Fleck’s comparative analyses of pictorial representations in medical science.

The standard image used in Science and Technology Studies (STS) for teaching the difference between “seeing” (for Fleck, “vague initial looking” of the sort experienced by the uninitiated layperson) and “seeing as” (for Fleck, “developed direct seeing of Gestalts” by the expert initiated into a thought-style and thought-collective) is the following:

duck-or-rabbit illustration

^ Famous rabbit-or-duck illustration (is it a duck? or a rabbit?).

Used for teaching that what & how we see is colored by our preexisting beliefs about the world. (Even the way I frame this — whether I put the label “duck” or “rabbit” first in the caption — can influence visual interpretation.)
   According to Fleck, there is no “pure observation” without assumptions — even in science. (Fleck, 1979, 90)
   “There is no visual perception except by ideovision and there is no other kind of illustration than ideograms.” (Fleck, 1979, 141)

In the cant of STS: all facts are theory-laden.

The notion is readily enough introduced through an analogy with vision, that humans see in certain diagrams only one of several possibilities — for example, either a rabbit or a duck. The first impact of this on students typically is the impression that there aren’t any objective facts in science after all (or anywhere else, for that matter), that everything is a matter of interpretation, that knowledge is constructed, and that we cannot really discover anything about the world around us (if, indeed, there is a world around us). But further thought and observation reveal that some facts are indubitably more theory-laden than others, to a degree that matters quite profoundly: one can see a rabbit or a duck, but few people would see here a map or an extraterrestrial, let alone a typewriter or a screwdriver. That theory-ladenness is a matter of degree leaves open the possibility that there really is something objectively out there, even though our knowledge of it rests on interpretation. There are actually black lines and white spaces in that diagram, though there may not really be a duck or a rabbit. So the realism of scientists can be seen as legitimate even as we learn not to accept as necessarily real every item that is talked about by scientists as though it were real.

(Bauer, Scientific Literacy and the Myth of the Scientific Method, 17–18)

Fleck was an early constructivist who believed that even “the best established medical facts,” such as “the so-called Wassermann reaction,” are dependent on history and culture and, as such, “lend themselves to epistemological investigation” — “How, then, did this empirical fact originate and in what does it consist?” (Fleck, 1979, xxviii). For Fleck, “Although it is sensed as something ‘objectively given’, a fact is determined by the respective thought-collective which knows it through an actual thought-style.” (Cohen & Schnelle, Introduction, xiii)

This holds for the facts of medical images, as well — even those associated with “professional science in its vademecum (or handbook) form” (Fleck, 1979, 118) — which Fleck illustrates by comparing the visuals and scientific descriptions in anatomy textbooks.

Our first EXCERPT is from Chapter 2 (pp. 30–38) of Fleck’s monograph, specifically Examples 4 and 5 from the section in Chapter 2 giving “a few examples ... showing the various degrees of tenacity of viewpoints” (Fleck, 1979, 28) in scientific cognition:

Leafing through modern anatomical atlases and gynecological textbooks, I found many good illustrations but not a single natural one. All had been touched up in appearance, and were schematically, almost symbolically, true to theory but not to nature.

(Fleck, 1979, 33)

The pictures Fleck reproduces of a woman’s uterus (from the 17th and 20th centuries) are presented as evidence for his larger argument that

Analogously to social structures, every age has its own dominant conceptions as well as remnants of past ones and rudiments of those of the future. It is one of the most important tasks in comparative epistemology to find out how conceptions and hazy ideas pass from one thought style to another, how they emerge as spontaneously generated pre-ideas, and how they are preserved as enduring, rigid structures [Gebilde] owing to a kind of harmony of illusions. It is only by such a comparison and investigation of the relevant interrelations that we can begin to understand our own era.

(Fleck, 1979, 28)

Unlike Kuhn’s better-known theory of the structure of scientific revolution, for Fleck,

The conception of scientific development as a cumulative and progressive process is replaced by that of development as a continual changing of the style of thought. Thought-styles are historically developed, sociologically conditioned and mutually interacting phenomena. The dynamic implied in this structure becomes the force of scientific development. “Development” is not understood as progressive or evolutionary. Rather it means only that attention can be directed to new problems. At the same time, other problems lose their stylistically conformed character. They become irrelevant, they are no longer “perceivable”. As new knowledge emerges, old is lost. Unlike with Kuhn, this development does not occur in leaps and bounds; rather the presuppositions of knowledge change continuously, mostly without the awareness of the scientists involved. However, certain “proto-ideas” can “survive” even throughout longer periods of time: they serve a number of thought-collectives and generations of scientists as heuristic guidelines. They live on because they are taken up and used again by each of the newly developed thought-collectives. They are reinterpreted within the framework of the new thought-style and in accordance with its changed presuppositions. Old and new merge. Thus we can speak of continuity in the succession of styles of thought.
     Within this framework, Fleck reformulates the concept of a scientific fact. A fact is no longer something given independently of scientific activity, because the socially conditioned and historically developed thought-style forces itself on scientific knowledge, the presuppositions of which are actively posited by the thought-collective. What scientists are looking for, on the other hand, are the passive linkages which arise from these active postulations or “settings”. Once certain presuppositions are chosen and accepted, the collective can no longer decide on the passive linkages implied by them, but rather experiences them, perceives them, as “laws of nature”. The scientist can relate to such a perception only “passively” or “reactively”. Fleck describes the process of knowledge of a fact as the development of such “avisos of resistance”, notices which restrict the freedom of the scientist to make arbitrary stipulations. If a thought-collective wants to integrate such a resistance into its previously developed system of thought or opinion, it develops it so that it becomes an increasingly clear constraint on thought — a “force of thought” — and finally an immediately perceivable Gestalt. Although it is sensed as something “objectively given”, a fact is determined by the respective thought-collective which knows it through an actual thought-style.

(R. S. Cohen and T. Schnelle, Introduction, Cognition and Fact: Materials on Ludwick Fleck, 1986, xii–xiii)

Our second EXCERPT is from Chapter 4 (pp. 133–145) of Fleck’s monograph, with further case studies in scientific observation drawn from early and recent anatomical textbooks. Here, Fleck analyzes medical texts and diagrams from several different periods and cultures to illustrate how particular scientific statements may be viewed as the products of thought styles coming up against and contending with empirical resistances. He finds striking examples of how different patterns and habits of expression result in different theories and conclusions, rightly noting that “Books on anatomy from the seventeenth and eighteenth centuries contain absolutely superb graphic pictures of nerve men and vein men which can never be found in modern textbooks.” (Fleck, 1979, 136)

Prior to these philosophical reflections on medical themes, he cautions:

To prevent misunderstandings it must once again be stressed that it is not the purpose of these pronouncements to play off earlier viewpoints against those of today, or those of leading research workers against textbook views. It is altogether unwise to proclaim any such stylized viewpoint, acknowledged and used to advantage by an entire thought collective, as “truth or error.” Some views advanced knowledge and gave satisfaction. These were overtaken not because they were wrong but because thought develops. Nor will our opinions last forever, because there is probably no end to the possible development of knowledge just as there is probably no limit to the development of other biological forms.
     Our sole purpose has been to demonstrate how even specialized knowledge does not simply increase but also basically changes. Yet we do not want to confine ourselves merely to some banal statement about the transience of human knowledge....

(Fleck, 1979, 64)

No fear of that! Fleck’s philosophy and sociology of science was so far ahead of its time that it took over 40 years after initial publication of his monograph for thought-styles to change and for his own “more original and bolder” thought to take hold. As Fleck himself noted in a different context:

In the history of the Wassermann reaction we described the process by which personal and provisional journal science becomes transformed into collective, generally valid vademecum science. This appears initially both as change of conceptual meaning and as reformulation of the problem, and subsequently as an accumulation of collective experience, the formation of a special readiness for directed perception and specialized assimilation of what has been perceived. Some of this esoteric communication of thought occurs already within the scientist himself. He conducts a dialogue with himself as he ponders, compares, and makes decisions. The less his decision rests on adaptation to vademecum science and the more original and bolder his personal thought style, the longer it will take to complete the process of collectivizing his results.

(Fleck, 1979, 120)

Translation issues

Scholars surmise that one reason why Fleck’s ideas took so long to assimilate had to do with language issues: “The reason for the long neglect is clear: all but one [of the articles in Fleck’s philosophical oeuvre, printed in the late 1920s, the mid 1930s, and after the war in 1946 and 1947] were published in the Polish language, and thus difficult to reach for foreign readers.” (Cohen & Schnelle, Introduction, ix)

In addition, his German-language monograph published at Basel, Switzerland in 1935, entitled Entstehung und Entwicklung einer wissenschaftlichen Tatsache. Einführung in die Lehre vom Denkstil und Denkkollektiv, was not an easy book to translate when it did finally come to the attention of those with the resources to launch an international rebirth.

Written in German by a Jewish physician-scholar from Poland, first published in Switzerland, it has been translated in Oxford and Regensburg, edited in New York and Regensburg, and appears under a Chicago imprint. In effect, this translated edition is itself a collective outcome of the very type Fleck describes.

(T. J. Trenn and R. K. Merton, Preface, Genesis and Development of a Scientific Fact, 1979, xiv)

In their Preface, Trenn and Merton attempted to justify their “intepretive translation, which seeks to remain faithful to Fleck’s complex ideas while conveying them in a readable fashion” (Genesis, 1979, xv):

The translation was a difficult task. Fred Bradley in Oxford, who has translated over thirty-five books, accepted this project as a unique challenge. Merton and I agreed that a close and literal translation of the complex and often idiosyncratic original would only result in an unreadable English version. Bradley’s initial translation was largely reworked by the editors from the point of view of interpretation, terminology, and style. In the interests of preserving accuracy and conveying meaning, this edited version departed at times from the German original, and so was resubmitted to Bradley for further discussion and compromise where appropriate. The final result is an interpretative translation, which seeks to remain faithful to Fleck’s complex ideas while conveying them in a readable fashion.
     A word must be added about some of the key terms. Some words quite resist adequate translation, and perhaps none more than the central terms Denkstil and Denkkollektiv. One might have justified the retention of Denkstil following the precedent of Jugendstil, but we preferred to provide a translation. For the German Denkstil it seemed best to adopt “thought style” as a straightforward equivalent, although it transmits few of the cultural overtones inherent in the original and places undue emphasis upon presumed rational processes. The German word Denkstil was introduced by Karl Mannheim in 1925, and remains in current use.
     We were less inclined initially to preserve the original Denkkollektiv, since “thought collective” seemed awkward beyond ready acceptance. The term Denkkollektiv appears to have been introduced by Fleck and is not standard German usage. We considered introducing a neologism, but a close editing of the translation indicated the necessity of retaining “thought collective” if the conceptual balance of the text was to be preserved. Fleck uses the adjective kollektiv and the noun Kollektiv in a great variety of related contexts throughout the text, and it would have been unjustified not to translate this with the intended sociological term “collective.” Since Denkkollektiv refers to that same collective which engages in kollektive Arbeit, has a kollektiven Denkstil, produces kollektive Erfahrung, has both kollektive Gedanken and kollektive Vorstellungen, operates according to kollektiven Denklinien, and produces kollektive Gebilde, we have designated it simply the “thought collective” in order to maintain unity throughout the work. The various and rather different senses in which Fleck uses Denkkollektiv will thus not be assigned different English terms as was initially considered but will in each case be translated as “thought collective.” But for the fact that Fleck explicitly meant “collective” rather than “community” — a highly contentious terminological issue — we might have been able to adopt the symmetry of “style of thought” and “community of thought.” The “thought collective of modern science” (moderne wissenschaftliche Denkkollektiv) could then have been conveniently rendered as the “modern scientific community.” But we have refrained from such license throughout the translation.
     It should be noted that we entertained the possibility of using “school of thought” for Denkstil and/or Denkkollektiv. But “school of thought” is especially ambiguous in the context of Fleck’s ideas, carrying aspects of both Denkstil and Denkkollektiv. It is thus not appropriate in a context where these must be considered distinctive even though they are inseparable one from the other. Utilization of the familiar “cognitive style” and “cognitive community” based on the Latin cognoscere, would be misleading, since both Denkstil and Denkkollektiv are based on the allied but different cogitare.
     There are other difficult terms. The word Lustseuche as used by Fleck cannot always be rendered as “syphilis” but must often retain the crucial element of punitive plague or scourge resulting from lecherous and sinful fornication. While “lecher’s-disease plague,” or “coital plague” were considered, the meaning seems best carried by “carnal plague or scourge.” Thus, depending on the context, Lustseuche has been rendered variously by “the carnal scourge,” “lues venerea,” or “the great pox,” where the latter term balances nicely with “the French pox” as well as with the non­venereal variola “small pox” and “swine pox” in certain portions of the text. A similar difficulty arose in the case of Sinn-Bild and Sinn-Sehen. At one point Fleck identifies Sinn-Bild with the technical term “ideogram,” so that we adopt the neologism “ideovision” for Sinn-Sehen — the faculty to apprehend, visually perceive, or formulate ideograms. Such terms as “collective experience” have sometimes been given in the forms “experience of the collective,” “mood of the collective,” or “effort of the collective” to emphasize the sense conveyed by the original. The “thought style of modern science” seems preferable to the “modern scientific thought style” so as not to overload the term with the significance of a general cultural trait. The frequent appearance of “mood” for Stimmung is generally interchangeable with “disposition” throughout the text; “temper” or even “temperament” could have been used in most contexts. Other terms that are of sufficient difficulty or interest are noted editorially as they arise.

(T. J. Trenn and R. K. Merton, Preface, Genesis and Development of a Scientific Fact, 1979, xv–xvii)

For the most part, scholars able to read Fleck’s work in the original have been unhappy with the resulting “intepretive translation” which one critic, posting to the Science as Culture discussion list on 4/15/1999, described as a “paraphrase with serious defects.”

Cohen and Schnelle, editors of Cognition and Fact: Materials on Ludwick Fleck, are also critical of the 1979 “intepretive translation,” noting,

Fleck’s language was unusual: although very fluent and innovative, it was not always grammatically correct. This is true for his publications in both German and Polish. No doubt, German, or rather an educated Austro-German dialect, was Fleck’s second mother tongue next to Polish. These circumstances alone constitute a heavy burden for any translator who seeks to preserve the originality of Fleck’s language. Translating into the English, there are problems of two different kinds. On the one hand Fleck uses expressions such as “Sinn”, “erkennen”, etc. There are no expressions in the English language which were equivalent to their understanding in the middle-European tradition. On the other hand Fleck invented some expressions himself, such as “Denkkollektiv”, “Denkverkehr”, “Denkzwang”, “Sinnsehen”, “Widerstandsaviso” etc. The translator of such expressions, which had been invented (or used with an innovative connotation), must try also to be innovative, and in a similar way. This is of course nearly impossible. A reader knowing that the text is a translation, not an original manuscript, will usually reject such suggestions as not being adequate. However, when in doubt, we think a translation of an expression should sound awkward rather than go too far from the structures contained in the original.
     Unfortunately to our way of thinking, the English translation of Fleck’s monograph (Fleck 1979) is somewhat imprecise, particularly in its formulation of sociological concepts. For example, Fleck’s term “soziales Gedächtnis” has been translated simply as “society” (1979: 2). There seems to be no reason why “social memory” would not have been adequate. Although Fleck seldom uses this particular term, it exemplifies the shortcomings of this edition: it fails to bring out adequately the aspect of social activity on the part of individuals bound up in social interactions. Another example: “Bedingtheit” is better translated as “conditionally” or “conditionedness” rather than “dependence” (1979: 9, although later on the expression “conditioning” is also used). Similarly, “Koppelungen” are “linkages” (or “couplings”) rather than “associations” or “connections”.
     In view of this disagreement about translation, it seems useful to present here a glossary of the most important expressions employed by Fleck in Polish and German, together with our choice for their corresponding English translation: ....

(R. S. Cohen and T. Schnelle, Introduction, Cognition and Fact: Materials on Ludwick Fleck, 1986, xiv–xv)

I dwell on this at length in order to call attention to the many editorial decisions at play in the “interpretive translation” of Fleck’s original monograph which I have digitized here.

It is all too easy for readers to forget that all texts — not just such a controversial “interpretive translation” — are constructed by multiple voices, and that literal interpretations which ignore the conditionedness of the text are always inadequate.

[ To view all 4 hover-box notes for this Editor’s Introduction,
grouped together on a separate Web page, click/tap here]


Bauer, Henry H. Scientific literacy and the myth of the scientific method. Champaign, IL: University of Illinois Press, 1992.

As reviewed in the trade journal, Publishers Weekly:
   “To put some of the adventure back in everyday science, this study is the place to start. Bauer, chemistry professor at Virginia Polytechnic Institute, upends current contentions about science literacy in a small, dense book that could be the nucleus of a restructuring of how science works in our culture, or, in the author’s terms, how its reputation works. The call for more science literacy is a shibboleth in this STS-based (science, technology, society) exposition, which is a sort of deconstruction of the general image of science. Excising popular fallacies, Bauer argues that science is particular knowledge embedded in its time’s social context and, therefore, in continuous change. His critique is radical: demystify the science we learn as fact (‘textbook science’), keep ‘frontier science’ (research) from being overwhelmed by structural forces in technocracy, avoid ‘scientism’ as a basis of social policy. Science can be made to serve us better, stresses the author, but not as a new mythology.”

Cohen, Robert, and Thomas Schnelle, eds. Cognition and Fact: Materials on Ludwick Fleck. Dordrecht: D. Reidel, 1986.

As described by the editors, “The essays on Ludwik Fleck’s theory of knowledge and science which have been gathered in [Part III of] this book are the results of two scientific meetings organized to honor him: the first took place during three days in 1981 in Hamburg. This ‘Colloquium Ludwik Fleck’ was organized by Lothar Schäfer and Thomas Schnelle within their Fleck research project. The second was a symposium arranged by Robert S. Cohen at the Wissenschaftskolleg zu (West) Berlin in 1984. There it was possible to initiate a discussion with physicians concerning Fleck’s philosophical reflections on medical themes (see, e.g., the papers by Zalc and Löwry).  ¶  These two meetings marked a turning-point in the reception of Fleck as a philosopher and sociologist....” (Cohen & Schnelle, Introduction, xvii)
  Part II reprints Fleck’s published articles on the philosophy of science (most available here for the first time in English):
   2.1 “Some Specific Features of the Medical Way of Thinking” (1927)
   2.2. “On the Crisis of ‘Reality’” (1929)
   2.3 “Scientific Observation and Perception in General” (1935)
   2.4 “The Problem of Epistemology” (1936)
   2.5 “Problems of the Science of Science” (1946)
   2.6 “To Look, To See, To Know” (1947)
   2.7 “Crisis in Science” (unpublished, 1960)

Fleck, Ludwik. Entstehung und Entwicklung einer wissenschaftlichen Tatsache. Einführung in die Lehre vom Denkstil und Denkkollektiv. Basel: Benno Schwabe, 1935.

Fleck’s original German-language monograph of 1935, reissued in English translation (without the subtitle) in 1979.

Fleck, Ludwik. Genesis and Development of a Scientific Fact. Edited by Thaddeus J. Trenn and Robert K. Merton. Translated by Frederick Bradley and Thaddeus J. Trenn. Chicago: University of Chicago Press, 1979.

An “intepretive translation” of the monograph of 1935, “which seeks to remain faithful to Fleck’s complex ideas while conveying them in a readable fashion” (Preface, Genesis and Development of a Scientific Fact, 1979, xv).
   Fleck’s monograph consists of a Prologue and 4 chapters:
  (Chapter 1) “How the Modern Concept of Syphilis Originated”
  (Chapter 2) “Epistemological Conclusions from the Established History of a Concept”
   (Chapter 3) “The Wassermann Reaction and Its Discovery”
   (Chapter 4) “Epistemological Considerations Concerning the History of the Wassermann Reaction”

ornament (quill, at rest in inkpot)

epistemology — I.e., the science which deals with the origin and method of knowledge. ::

“seeing” vs. “seeing as” — An obvious instance of the difference between “seeing” and “seeing as” will be familiar to any of us who have stared blankly at the chaotic medical images produced by x-ray, CT, and MRI machines. It takes quite a while before even the most attentive and studious parent or pet-parent is able to find meaning in these images, nor will we ever be able to see with the same depth of understanding as the radiologist, surgeon, veterinarian, and other trained experts who rely on such images to do their work. ::

constructivist — Epistemologically, Fleck was “an advocate of a radical nominalism and constructivism.” (Cohen & Schnelle, Introduction, xi) He was not, however, a skeptic: “The views outlined here should not be construed as skepticism. We are certainly capable of knowing a great deal. If we cannot know ‘everything,’ according to the traditional position, it is simply because we cannot do much with the term ‘everything,’ for every new finding raises at least one new problem: namely an investigation of what has just been found. The number of problems to be solved thus becomes infinite and the term ‘everything’ meaningless.” (Fleck, 1979, 51)
  Ultimately, Fleck believed in “reality” and the truths of science. “Truth is not ‘relative’ and certainly not ‘subjective’ in the popular sense of the word. It is always, or almost always, completely determined within a thought style.... Truth is not a convention, but rather (1) in historical perspective, an event in the history of thought, (2) in its contemporary context, stylized thought constraint.” (Fleck, 1979, 100) ::

recent — I.e., recent to Fleck, when composing his monograph in 1934. ::