Kotarbiński is one of the leading figures in the Lvov-Warsaw school of Polish philosophy. We summarize the development of Kotarbiński’s thought from his early nominalism and ‘pansomatistic reism’ to the later doctrine of ‘temporal phases’. We show that the surface clarity and simplicity of Kotarbiński’s writings mask a number of profound philosophical difficulties, connected above all with the problem of giving an adequate account of the truth of contingent (tensed) predications. The paper will examine in particular the attempts to resolve (...) these difficulties on the part of Leśniewski. It will continue with an account of the relations of Kotarbińskian reism to the ontology of things or entia realia defended by the later Brentano. Kotarbiński’s identification of Brentano as a precursor of reism is, it will be suggested, at least questionable, and the paper will conclude with a more careful attempt to situate the Brentanian and Kotarbińskian ontologies within the spectrum of competing ontological views. (shrink)

This book is a survey of the most important developments in Austrian philosophy in its classical period from the 1870s to the Anschluss in 1938. Thus it is intended as a contribution to the history of philosophy. But I hope that it will be seen also as a contribution to philosophy in its own right as an attempt to philosophize in the spirit of those, above all Roderick Chisholm, Rudolf Haller, Kevin Mulligan and Peter Simons, who have done so much (...) to demonstrate the continued fertility of the ideas and methods of the Austrian philosophers in our own day. For some time now, historians of philosophy have been gradually coming to terms with the idea that post-Kantian philosophy in the German-speaking world ought properly to be divided into two distinct traditions which we might refer to as the German and Austrian traditions, respectively. The main line of the first consists in a list of personages beginning with Kant, Fichte, Hegel and Schelling and ending with Heidegger, Adorno and Bloch. The main line of the second may be picked out similarly by means of a list beginning with Bolzano, Mach and Meinong, and ending with Wittgenstein, Neurath and Popper. As should be clear, it is the Austrian tradition that has contributed most to the contemporary mainstream of philosophical thinking in the Anglo-Saxon world. For while there are of course German thinkers who have made crucial contributions to the development of exact or analytic philosophy, such thinkers were outsiders when seen from the perspective of native German philosophical culture, and in fact a number of them found their philosophical home precisely in Vienna. When, in contrast, we examine the influence of the Austrian line, we encounter a whole series of familiar and unfamiliar links to the characteristic concerns of more recent philosophy of the analytic sort. As Michael Dummett points out in his Origins of Analytic Philosophy, the newly fashionable habit of referring to analytic philosophy as "Anglo-American" is in this light a "grave historical distortion". If, he says, we take into account the historical context in which analytic philosophy developed, then such philosophy "could at least as well be called "Anglo-Austrian" (1988, p. 7). Much valuable scholarly work has been done on the thinking of Husserl and Wittgenstein, Mach and the Vienna Circle. The central axis of Austrian philosophy, however, which as I hope to show in what follows is constituted by the work of Brentano and his school, is still rather poorly understood. Work on Meinong or Twardowski by contemporary philosophers still standardly rests upon simplified and often confused renderings of a few favoured theses taken out of context. Little attention is paid to original sources, and little effort is devoted to establishing what the problems were by which the Austrian philosophers in general were exercised -- in spite of the fact that many of these same problems have once more become important as a result of the contemporary burgeoning of interest on the part of philosophers in problems in the field of cognitive science. (shrink)

The rediscovery in the mid-1970s of Ludwik Fleck's initially neglected monograph, Entstehung und Entwicklung einer Wissenschaftlichen Tatsache, published in 1935 and translated in 1979 as Genesis and Development of a Scientific Fact, has resulted in extensive, still ongoing, secondary writings, mainly within the humanities. Fleck has been interpreted as furthering a relativistic conception of science. Nowadays, he is often viewed as an important contributor to contemporary sociology of science and a forerunner to Thomas Kuhn. Fleck's account of the Wassermann reaction, (...) which forms the basis of his epistemology, has been praised as developed by a scientist well acquainted with the field in question. Because of the scarcity of available material on Fleck, however, the question of his sources has remained an unsolved issue. In the present article, an alternative reading is suggested. By focusing on the scientific content of the monograph, mainly neglected in the modern interpretations of Fleck, and on the so far overlooked sources of his writings traced back to their German origin, a better understanding of Fleck's account of the Wassermann reaction can be given. The consequences of this alternative reading for the conception of Fleck's monograph and for the impetus of his mission are discussed. (shrink)

The sociotechnical domain is the realm of scientists, the communities and institutions they form, and the tools and instruments they use to create, disseminate, and preserve knowledge. This paper reviews current scientonomic theory concerning this domain. A core scientonomic concept is that of an epistemic agent. Generally, an agent is an entity capable of intentional action—action that has content or meaning due to its purposeful direction towards a goal. An epistemic agent is one whose actions are the taking of epistemic (...) stances, such as acceptance or rejection, towards epistemic elements, like theories or questions. An epistemic agent must semantically understand the propositions in question, and their alternatives, and choose among them with reason, with the motive of acquiring knowledge. The most obvious example of an epistemic agent is an individual human being. Rejecting the network of practitioners view, current scientonomic theory argues that appropriately organized communities of scientists can also function as epistemic agents. Communal epistemic agents are of particular scientonomic importance. Whereas the methods of theory assessment of individual scientists can be idiosyncratic, scientonomic theory contends that the taking of epistemic stances by scientific communities is a lawful, rule governed process. A second concept of central importance is that of an epistemic tool. A physical object or system is an epistemic tool for some epistemic agent if there is a procedure by which the tool can provide an acceptable source of knowledge under the method employed by that agent. (shrink)

Ludwik Fleck is known mainly for his pioneering studies of science as a social activity. This text investigates a different aspect of Fleck’s epistemological thought—his engagement with normative aspects of medicine and public health and their political underpinnings. In his sinuous professional trajectory, Fleck navigated between two distinct thought styles: fundamental microbiological research and practice-oriented investigations of infectious diseases. Fleck’s awareness of tensions between these two approaches favored the genesis of his theoretical reflections. At the same time, his close observation (...) of medical and epidemiological practices led him to the conclusion that collectively produced scientific facts are situated and fragile. Thought collectives, Fleck explained, can err or yield to external pressures, with potentially disastrous consequences. While Fleck the reflexive experimental scientist has been creatively translated into the science studies idiom, Fleck the reflexive practical microbiologist and public health expert still awaits inspired translation. (shrink)

Ludwik Fleck is remembered for his monograph published in German in 1935. Reissued in 1979 as Genesis and development of a scientific fact Fleck’s monograph has been claimed to expound relativistic views of science. Fleck has also been portrayed as a prominent scientist. The description of his production of a vaccine against typhus during World War II, when imprisoned in Buchenwald, is legendary in the scholarly literature. The claims about Fleck’s scientific achievements have been justified by referring to his numerous (...) publications in international scientific journals. Though frequently mentioned, these publications have scarcely been studied. The present article discusses differences in interpretation and evaluation of science in relation to the background of the interpreters. For this purpose Fleck’s scientific publications have been scrutinized. In conjunction with further sources reflecting the desperate situation at the time in question, the results of the study account for a more restrained picture of Fleck’s scientific accomplishments. Furthermore, based on the review of the latter, certain demands characterizing good science could be articulated. The restricted possibilities of those not trained in science or not possessing field specific knowledge, evaluating science are discussed, as are also formal aspects of scientific papers and questions related to research ethics. (shrink)

Ludwik Fleck’s theory of thought-styles has been hailed as a pioneer of constructivist science studies and sociology of scientific knowledge. But this consensus ignores an important feature of Fleck’s epistemology. At the core of his account is the ideal of ‘objective truth, clarity, and accuracy’. I begin with Fleck’s account of modern natural science, locating the ideal of scientific objectivity within his general social epistemology. I then draw on Fleck’s view of scientific objectivity to improve upon reflexive accounts of the (...) origin and development of the theory of thought-styles, and reply to objections that Fleck’s epistemological stance is self-undermining or inconsistent. Explicating the role of scientific objectivity in Fleck’s epistemology reveals his view to be an internally consistent alternative to recent social accounts of scientific objectivity by Harding, Daston and Galison. I use these contrasts to indicate the strengths and weaknesses of Fleck’s innovative social epistemology, and propose modifications to address the latter. The result is a renewed version of Fleck’s social epistemology, which reconciles commitment to scientific objectivity with integrated sociology, history and philosophy of science. (shrink)

This article analyses the slippery notions of the normal and normality in select works of Richard von Krafft-Ebing (1840–1902) and Sigmund Freud (1856–1939) and argues that homosexuality became a ‘boundary object’ between the normal and the abnormal in their works. Constructing homosexuality as ‘normal enough’ provided these two key thinkers of the fin de siècle with an opportunity to challenge societal and medical norms: Krafft-Ebing did this through mapping perversions; Freud, by challenging perceived norms about sexual development more broadly. The (...) article submits that the scientific logic presented in Krafft-Ebing’s seminal case study compilation Psychopathia Sexualis and Freud’s early theoretical writings and cases, including Three Essays on the Theory of Sexuality (1905), was itself haunted by notions of norms and the normal that were not always easy to resolve, and sometimes involved a certain amount of inspired conjecture on the part of both thinkers in order to develop and validate their differing tripartite models of normality. Krafft-Ebing imagined homosexuality as a variation of the normal by generalizing a gay male experience. He also recorded the obstreperous cases of homosexual women based largely inside the clinic but by and large ignored this evidence. Freud inextricably bound homosexuality to normality (and vice versa) by redefining homosexuals as a group to include individuals with unconscious same-sex desire. Doing so allowed him to conceptualize the fear of homosexuality as crucial in the formation of neurosis and psychosis, and at the same time put him at odds with relevant early identity politics. (shrink)

Ludwik Fleck is widely recognized as a precursor of Science and Technology Studies, but his case study on the development of the Wassermann reaction as a test for detecting syphilis has never been subjected to detailed empirical scrutiny. The fact that Fleck?s monograph is based on a limited set of documentary sources makes his work vulnerable to uncharitable critics. The problematic relation between thought collective and individual scientists in Fleck?s theoretical approach is another reason for a systematic re-examination of his (...) case study, using materials on the early period in the history of the Wassermann reaction (1906?1912). My re-examination highlights several problems in Fleck?s account: a misinterpretation of the switch from antigen detection to antibody detection; a neglect of the ?clinical connection?; an overemphasis on the importance of collective experience leading to implausible views on gross retrospective distortions supposedly inflicted by this experience upon the memories of individual participants; and, finally, a misjudgement of the significance of the acrimonious dispute over the intellectual ownership of the Wassermann reaction. What remains unscathed is Fleck?s picture of a zig-zag course of development from false initial assumptions via detours and cul-de-sacs to a clinically usable test in the end. (shrink)

The present thesis is based on a scientifically informed reading of Fleck. In addition to the monograph, the material includes his additional philosophical writings and also his internationally published scientific articles. The sources provided by Fleck have been traced back to the time of their origin. Based on the above material, it is argued that rather than relativizing science, and thereby deeply influencing Kuhn, Fleck, attempting to participate in the current debates, is an ardent proponent of science, offering an internal (...) account of its pursuit that accords with his often-contested epistemic concepts. The exposure of his description of the Wassermann reaction discloses a highly selected reading of the, at the time, available sources, but also its relation to the current debate on Einzelwissenschaften, or the standing of new emerging disciplines versus age-old ones, all occasioned by the remarkable progress of science that also affected philosophy. The divide between philosophers and scientists on the philosophical implications of modern physics is exposed as well as Fleck’s heuristic use of the latter topic in his epistemology. A more realistic account of his scientific accomplishment is provided that includes the unfeasibility of the manufacturing of an anti-typhus vaccine based on urine. It is finally argued that the modern interpretation, or the received humanist view of Fleck, is based on the, at the time of the rediscovery of the monograph, already endorsed program of STS writers opposing a scientifically informed reading of his texts. (shrink)

This paper considers the foundational role of the contagium vivum fluidum—first proposed by the Dutch microbiologist Martinus Beijerinck in 1898—in the history of virology, particularly in shaping the modern virus concept, defined in the 1950s. Investigating the cause of mosaic disease of tobacco, previously shown to be an invisible and filterable entity, Beijerinck concluded that it was neither particulate like the bacteria implicated in certain infectious diseases, nor soluble like the toxins and enzymes responsible for symptoms in others. He offered (...) a completely new explanation, proposing that the agent was a “living infectious fluid” whose reproduction was intimately linked to that of its host cell. Difficult to test at the time, the contagium vivum fluidum languished in obscurity for more than three decades. Subsequent advances in technologies prompted virus researchers of the 1930s and 1940s—the first to separate themselves from bacteriologists—to revive the idea. They found in it both the seeds for their emerging virus concept and a way to bring hitherto opposing thought styles about the nature of viruses and life together in consensus. Thus, they resurrected Beijerinck as the founding father, and contagium vivum fluidum as the core concept of their discipline. (shrink)

This paper discusses essential elements of the philosophical works of Ludwik Fleck and their potential interpretation for the teaching and learning of science. In the early twentieth century, Fleck made substantial contributions to understanding the sociological character of the nature of science and explaining the embedding of science in society. His works have several parallels to the later and very popular work, The Structure of Scientific Revolutions, by Thomas S. Kuhn, although Kuhn only indirectly referred to the influence of Fleck (...) on his own theories. Starting from a short review of the life of Ludwik Fleck, his philosophical work and its connections to Kuhn, this paper elaborates upon and illustrates how his theories can be considered for science education in order to provide learners with a better understanding of the nature of scientific endeavor and the bi-directional science-to-society links. (shrink)

The present thesis is based on a scientifically-informed, contextualized and historicized reading of Ludwik Fleck. In addition to his monograph, the material studied includes his additional philosophical writings, his internationally-published scientific articles and two, thus-far-unstudied postwar Polish papers related to his Buchenwald experiences. The sources provided by Fleck have been traced back to the time of their origin. Based on the above material, it is argued that, rather than relativizing science and deeply influencing Kuhn, Fleck, attempting to participate in the (...) current debates, is an ardent proponent of science, offering an internal account of its pursuit that accords with his oft-contested epistemic concepts, e.g., Denkzwang, Sinnsehen and Kopplungen. The exposure of his description of the Wassermann reaction discloses a highly selective reading of the sources available at the time, but also reveals its relation to the current debate on Einzelwissenschaften, or the standing of new emerging disciplines versus age-old ones, all occasioned by the remarkable progress of science that has also affected philosophy. The divide between philosophers and scientists on the philosophical implications of modern physics is exposed, as is Fleck’s heuristic use of the latter topic in his epistemology. A more realistic account of his often-valued scientific accomplishments is provided. It is argued that the modern interpretation or received humanist view of Fleck is based on the opposition, at the time Fleck’s monograph was rediscovered, of STS writers to a scientifically-informed reading of his texts. An additional corrective to the received view of Fleck is found in some of his postwar Polish papers related his Buchenwald experiences. The latter might also provide an answer to some of the contradictions inherent in the modern mythology surrounding Fleck. In amply exposing the precarious situation of the time, and the complexity of the ethical issues at stake, Fleck’s papers in fact generate age-old philosophical questions still worth contemplating. (shrink)

This paper deals with Ludwik Fleck’s theory of thought styles and Michael Polanyi’s theory of tacit knowledge. Though both concepts have been very influential for science studies in general, and both have been subject to numerous interpretations, their accounts have, somewhat surprisingly, hardly been comparatively analyzed. Both Fleck and Polanyi relied on the physiology and psychology of the senses in order to show that scientific knowledge follows less the path of logical principles than the path of accepting or rejecting specific (...) conventions, where these may be psychologically or sociologically grounded. It is my aim to show that similarities and differences between Fleck and Polanyi are to be seen in the specific historical and political context in which they worked. Both authors, I shall argue, emphasized the relevance of perception in close connection to their respective understanding of science, freedom, and democracy. (shrink)

The concept of natural kind is center stage in the debates about scientific realism. Champions of scientific realism such as Richard Boyd hold that our most developed scientific theories allow us to “cut the world at its joints” (Boyd, 1981, 1984, 1991). In the long run we can disclose natural kinds as nature made them, though as science progresses improvements in theory allow us to revise the extension of natural kind terms.

The ArgumentWhen we actually perform an experiment, we do many different things simultaneously – some belonging to the realm of theory, some to the realms of methodology and technique; however, a great deal of what happens is expressible in terms of socially determined images of knowledge or in terms of concepts of reflectivity – second-order concepts – namely thoughts about thoughts.The emergence of experiment as a second-order concept in late antiquity exemplifies the historical development of second-order concepts; it is shown (...) to be rooted in the Sophists' cunning reason and is followed up in the work of Ptolemy, Copernicus and Galileo.Then, by way of epistemological explication, the three levels of representation of an experiment are shown to be analogous to Baxandall's three levels of representation of a picture.Finally it is shown that such an interpretation only makes sense in terms of two-tier thinking: realism, inside a conceptual framework which is chosen or arrived at, relativistically. (shrink)

Based on the paradigm of Constructive Descriptions and Situations, we introduce NIC, an ontology of social collectives that includes social agents, plans, norms, and the conceptual relations between them. Norms are distinguished from plans, and their relations are formalized. A typology of social collectives is also proposed, including collection of agents, knowledge community, intentional collective, and normative intentional collective. NIC, represented as a first-order theory as well as a description logic for applications requiring automated reasoning, provides the expressivity to talk (...) about the contexts (social, informational, circumstantial, and conceptual), in which collectives make and produce sense within the interplay of plans and norms. (shrink)

The problem of how to handle interesting but ignored thinkers of the past is discussed through an analysis of the case of Ludwik Fleck. Fleck was totally ignored in the ?30s and declared an important thinker in the 70s and ?80s. In the first case fashion ignored him and in the second it praised him. The praise has been as poor as the silence was unjust. We may do such thinkers more justice if we recognize that intellectual society is fickle, (...) that we cannot make amends in many cases, but that we can do such thinkers justice by treating them critically ? even if this means explaining away any impact they might have had. If we wish to be autonomous and independent of fashion, we must abandon efforts to use the making of amends the occasion for making intellectual society seem fairer than it is. (shrink)

In 1948 Ludwik Fleck published a paper in Polish discussing the use of humans in medical experiments, thereby addressing his peers. Though the paper has so far not been translated or studied, it has been taken to indicate Fleck’s deep commitment to ethical questions, notably the question of informed consent. In being written by a former victim of the Nazi policy and a survivor of the Holocaust also acting as an expert witness in the trial of the IG Farben in (...) Nuremberg, the paper is of interest. A scrutiny of Fleck’s text and related sources discloses, however, not only the complexity of the issue at the centre of the Nuremberg trial, but also Fleck’s unexpected stance in seemingly adducing his arguments from both the German defendants and the prosecution, heavily informed by US scientists. Further, the contentious discussion of the past in Fleck’s paper reveals its links to modern bioethical discussion. Though sometimes oblivious of that past, it still faces the same questions. (shrink)

Kollaboration und Konkurrenz gibt es in der Wissenschaft zwischen Individuen oder verschiedenen Gruppen, größeren Organisationen, Schauplätzen und Nationalstaaten. Die Spannung zwischen individuellem Ansehen und Gruppenmeriten oder individuellem Ehrgeiz und Gruppenleistung ist der wissenschaftlichen Arbeit inhärent und trägt zu ihrem Erfolg bei. Die Autorin vergleicht zwei soziale Modelle der Wissenschaft, die entwickelt wurden, als Wissenschaftler im 20. Jahrhundert zunehmend begannen kollaborativ zu forschen: Michael Polanyis individualistische Freie-Markt-Republik der Wissenschaft und Ludwik Flecks Denkkollektiv. Diese beiden Modelle sollten Praktiken beschreiben und Ideale für (...) die Wissenschaft im allgemeinen auf der Grundlage der Erfahrungen spezialisierter Forschungsgruppen vorschreiben. Die Arbeitsgruppen von Linus Pauling und Dorothy Crowfoot Hodgkin dienen hier der Erläuterung der beiden Modelle. Die Autorin untersucht verschiedene Auswirkungen von Paulings und Hodgkins Praktiken auf das persönliche Ansehen des Direktors und der Mitarbeiter, und schließt mit der Frage, ob eine kollektive Wissenschaft möglich ist. (shrink)

: Since its almost serendipitous rediscovery in the late seventies, Fleck's monograph, Entstehung und Entwicklung einer wissenschaftlichen Tatsachee, initially published in 1935, translated into English in 1979 (Genesis and Development of a Scientific Fact), has been met with increasing acclaim within the philosophy and the sociology of science. In historizing, sociologizing and relativizing science, Fleck is claimed to have expressed prescient views on the history, philosophy and sociology of science and in deeply influencing Kuhn. Though the neglect of Fleck by (...) his contemporaries has been difficult to account for, the basis of his epistemology has evoked little interest, partly due to the lack of apparent sources. Fleck's philosophical writings, published between 1927 and 1939, indicate, however, a polemic, deeply ingrained in an ongoing debate, on the standing of old established scientific disciplines versus new and emerging ones, occasioned by the rapid changes within the natural sciences. Most obvious to the lay community, and also reflected in the new positivist philosophy, were the revolutionary changes within physics. As a participant in the debate, eagerly striving for recognition, Fleck used modern physic heuristically as the basis of his epistemology. The tracing of his sources, and the voices of other contemporaneous scientists opposing his views, are attempted. (shrink)

This volume, The Brazilian Studies in the Philosophy and History of Science, is the first attempt to present to a general audience, works from Brazil on this subject. The included papers are original, covering a remarkable number of relevant topics of philosophy of science, logic and on the history of science. The Brazilian community has increased in the last years in quantity and in quality of the works, most of them being published in respectable international journals on the subject. The (...) chapters of this volume are forwarded by a general introduction, which aims to sketch not only the contents of the chapters, but it is conceived as a historical and conceptual guide to the development of the field in Brazil. The introduction intends to be useful to the reader, and not only to the specialist, helping them to evaluate the increase in production of this country within the international context. (shrink)

Kollaboration und Konkurrenz gibt es in der Wissenschaft zwischen Individuen oder verschiedenen Gruppen, größeren Organisationen, Schauplätzen und Nationalstaaten. Die Spannung zwischen individuellem Ansehen und Gruppenmeriten oder individuellem Ehrgeiz und Gruppenleistung ist der wissenschaftlichen Arbeit inhärent und trägt zu ihrem Erfolg bei. Die Autorin vergleicht zwei soziale Modelle der Wissenschaft, die entwickelt wurden, als Wissenschaftler im 20. Jahrhundert zunehmend begannen kollaborativ zu forschen: Michael Polanyis individualistische Freie-Markt-Republik der Wissenschaft und Ludwik Flecks Denkkollektiv. Diese beiden Modelle sollten Praktiken beschreiben und Ideale für (...) die Wissenschaft im allgemeinen auf der Grundlage der Erfahrungen spezialisierter Forschungsgruppen vorschreiben. Die Arbeitsgruppen von Linus Pauling und Dorothy Crowfoot Hodgkin dienen hier der Erläuterung der beiden Modelle. Die Autorin untersucht verschiedene Auswirkungen von Paulings und Hodgkins Praktiken auf das persönliche Ansehen des Direktors und der Mitarbeiter, und schließt mit der Frage, ob eine kollektive Wissenschaft möglich ist. (shrink)

I shall elaborate more on the idea of anti-irrationalism proposed by the Polish analytic philosopher Kazimierz Ajdukiewicz, a prominent member of the Lvov-Warsaw School of philosophy and logic. In my reading, anti-irrationalism stands in opposition not only to overt irrationalism, which is made clear by the term itself, but also to all forms of rationalism that tip toward something like worship of reason. Having characterized anti-irrationalism as it originally appeared in Ajdukiewicz’s works, I shall propose a certain reformulation of it, (...) so as to capture a broader philosophical legacy in Poland, primarily, yet not exclusively the Lvov-Warsaw School. (shrink)

Although Ludwik Fleck is today recognized as one of the pioneers of the historical sociology of science, his historical and epistemological writings, most of them dating from the 1930s, long remained practically unknown. They were rediscovered following the mention of Fleck's principal work, the monographGenesis and Development of a Scientific Fact(1935) in the preface of Kuhn'sThe Structure of Scientific Revolutions(1962), and thanks to the efforts of W. Baldamus (1977) and his student T. Schnelle (1982) and of the editors of the (...) English translation of Fleck's book, R. K. Merton and T. J. Trenn. Fleck's work was studied by several scholars and was the subject of two meetings: “Colloquium Ludwik Fleck” (Hamburg, 1981) organized by L. Schaffer and T. Schnelle, and a symposium organized by R. S. Cohen (Berlin, 1984). Some of the papers presented at these meetings were published in Cohen and Schnelle 1986. Today, more than fifty years after the publication of his principal study, Fleck is on his way to becoming a “classic” of the sociology of science and of epistemology. (shrink)

This paper aims to trace individual as well as collective aspects of ‘sight styles’ in diagnostic computed tomography. Radiologists need to efficiently translate the visualized data from the living human body into a reliable and significant diagnosis. During this process, their visual thinking and the created images are incorporated into a complex network of other visualizations, communication strategies, professional traditions, and (tacit) visual knowledge. To investigate the interplay of collective as well as individual dimensions of diagnostic seeing, the concept of (...) ‘sight collective’ (Sehkollektiv) is developed. On the one hand, this concept is based on critical reading of Ludwik Fleck’s epistemological writings and his notions of thought collective (Denkkollektiv) and thought style (Denkstil). On the other hand, it is tested by means of qualitative empirical studies in a radiological university clinic (participatory observations and informal interviews). By employing this approach, the paper traces the collective foundations of a certain diagnostic sight. Moreover, it shows how the individual abilities of radiologists to perform stylized seeing rely remarkably on software-based interactions with the processed images and on tacit dimensions of visual knowledge. (shrink)