This paper follows the circuitous path of theories concerning the origins of viruses from the early years of the twentieth century until the present, considering RNA viruses in particular. I focus on three periods during which new understandings of the nature of viruses guided the construction and reconstruction of origin hypotheses. During the first part of the twentieth century, viruses were mostly viewed from within the framework of bacteriology and the discussion of origin centered on the “degenerative” or the “retrograde (...) evolution theory.” However, concomitantly, in the context of origin-of-life theorizing, the notion that viruses are vestiges of a prebiotic world was also being contemplated. In the 1960s the idea that viruses were genetic elements that “escaped” from cells became prevalent. These traditional hypotheses are being revisited nowadays by evolutionary virologists, who have placed them within a new conceptual framework that is supported by cutting-edge genomic and proteomic data. Two current, opposing scenarios of virus origin are presented. The philosophical dimensions of “revisiting” the original hypotheses are briefly discussed. (shrink)

In spite of several attempts to explicate the relationship between a scientific hypothesis and evidence, the issue still cries for a satisfactory solution. Logical approaches to confirmation, such as the hypothetico-deductive method and the positive instance account of confirmation, are problematic because of their neglect of the semantic dimension of hypothesis confirmation. Probabilistic accounts of confirmation are no better than logical approaches in this regard. An outstanding probabilistic account of confirmation, the Bayesian approach, for instance, is found to be defective (...) in that it treats evidence as a formal entity and this creates the problem of relevance of evidence to the hypothesis at issue, in addition to the difficulties arising from the subjective interpretation of probabilities. This essay purports to satisfy the need for a successful account of hypothesis confirmation by offering an original formulation based on the notion of instantiation of the relation urged by an hypothesis. (shrink)

This article shows how Lamarckism was essential in the birth of the French school of molecular biology. We argue that the concept of inheritance of acquired characters positively shaped debates surrounding bacteriophagy and lysogeny in the Pasteurian tradition during the interwar period. During this period the typical Lamarckian account of heredity treated it as the continuation of protoplasmic physiology in daughter cells. Félix d’Hérelle applied this conception to argue that there was only one species of bacteriophage and Jules Bordet applied (...) it to develop an account of bacteriophagy as a transmissible form of autolysis and to analyze the new phenomenon of lysogeny. In a long-standing controversy with Bordet, Eugène Wollman deployed a more morphological understanding of the inheritance of acquired characters, yielding a particulate, but still Lamarckian, account of lysogeny. We then turn to André Lwoff who, with several colleagues, completed Wollman’s research program from 1949 to 1953. We examine how he gradually set aside the Lamarckian background, finally removing inheritance of acquired characters from the resulting account of bacteriophagy and lysogeny. In the conclusion, we emphasize the complex dual role of Lamarckism as it moved from an assumed explanatory framework to a challenge that the nascent molecular biology had to overcome. (shrink)

In 1936, Frank Macfarlane Burnet published a paper entitled “Induced lysogenicity and the mutation of bacteriophage within lysogenic bacteria,” in which he demonstrated that the introduction of a specific bacteriophage into a bacterial strain consistently and repeatedly imparted a specific property – namely the resistance to a different phage – to the bacterial strain that was originally susceptible to lysis by that second phage. Burnet’s explanation for this change was that the first phage was causing a mutation in the bacterium (...) which rendered it and its successive generations of offspring resistant to lysogenicity. At the time, this idea was a novel one that needed compelling evidence to be accepted. While it is difficult for us today to conceive of mutations and genes outside the context of DNA as the physico-chemical basis of genes, in the mid 1930s, when this paper was published, DNA’s role as the carrier of hereditary information had not yet been discovered and genes and mutations were yet to acquire physical and chemical forms. Also, during that time genes were considered to exist only in organisms capable of sexual modes of replication and the status of bacteria and viruses as organisms capable of containing genes and manifesting mutations was still in question. Burnet’s paper counts among those pieces of work that helped dispel the notion that genes, inheritance and mutations were tied to an organism’s sexual status. In this paper, I analyze the implications of Burnet’s paper for the understanding of various concepts – such as “mutation,” and “gene,” – at the time it was published, and how those understandings shaped the development of the meanings of these terms and our modern conceptions thereof. (shrink)

This article concerns itself with the reception of Rous' 1911 discovery of what later came to be known as the Rous Sarcoma Virus (RSV). Rous made his discovery at the Rockefeller Institute for Medical Research which had been primarily established to conduct research into infectious diseases. Rous' chance discovery of a chicken tumor led him to a series of conjectures about cancer causation and about whether cancer could have an extrinsic cause. Rous' finding was received with some scepticism by the (...) scientific community that held that cancer was not infectious and favored explanations which located the origins of cancer in the inner mechanism of the cell. After 4 years of unsuccessful effort to isolate and further determine the virus Rous felt compelled to discontinue his work on cancer viruses. When 55 years later, the significance of Rous's discovery was attested by the award of the Nobel Prize, it opened up debates about the issues of delayed recognition and scientific reputation. This article also considers why Rous' hypothesis of a viral origin of cancer could not be incorporated into the existing body of knowledge about cancer before the 1950s. (shrink)

As soon as the SARS‐Cov2 disease was recognized by experts to potentially cause a serious pandemic, a three dimensional diagrammatic image of the virus, colored in strong red, conquered public media globally.This study confronts this iconic virus image with a historic image analysis of 33,000 biomedical articles on coronaviruses published between 1968–2020 and interviews with some of their authors.Only a small fraction of scientific virus publications entail images of the complete virus. Red as an alarm color is not used at (...) all by scientists who don't aim for a non‐scientific public.Circulation in this case concerns the movement of iconic images from a scientific context into a general public. On the basis of hps‐studies on scientific diagrams and especially on color use in scientific diagrams to convey specific messages in public, the paper discusses the role of the claim of public corona‐virus diagram as “scientific.”It points at relevant differences between most frequent scientific corona‐virus images and the diagrammatic image used in public. Both author‐ and readerships (in science and public) follow contrasting aims and values. Thus, the images meet non‐expert readers for whom the images entail very different – and potentially unintended – meanings then to virus experts. (shrink)

Incommensurability may be regarded as driving specialisation, on the one hand, and as posing some problems to interdisciplinarity, on the other hand. It may be argued, however, that incommensurability plays no role in either specialisation or interdisciplinarity. Scientific specialties could be defined as simply 'different' (that is, about different things), rather than 'incommensurable' (that is, competing for the explanation of the same phenomena). Interdisciplinarity could be viewed as the co- ordinated effort of scientists possessing complemetary and interlocking skills, and not (...) as the overcoming of some sort of incommensurable divide. This article provides a comprehensive evaluative examination of the relations between specialisation, interdisciplinarity, and incommensurability. Its aim is to defend the relevance of incommensurability to both specialisation and interdisciplinarity. At the same time, it aims at correcting the tendency, common among many philosophers, to regard incommensurability in a restrictive manner - such as, for example, as an almost purely semantic issue. (shrink)

An important question facing contemporary philosophy of science is whether the natural sciences in terms of their historical records exhibit distinguishing developmental patterns or structures. At least two philosophical stances are possible in answering this question. The first pertains to the plurality of the individual sciences. From this stance, the various sciences are analyzed individually and compared with one another in order to derive potential commonalities, if any, among them. The second stance involves a general philosophy of science in which (...) a thorough theory of the natural sciences is developed. The latter stance strives to account for more than possible commonalities among the sciences but also to provide a broad-spectrum philosophical framework to account for, or to explicate, the nature of science itself and its progress. In this paper, the second stance is taken in which an evolutionary philosophy of science is proposed. To that end, Thomas Kuhn’s evolutionary philosophy of science is initially discussed and critiqued. An evolutionary philosophy of science is then proposed based on a revision of Kuhn’s evolutionary philosophy of science in terms of George Gaylord Simpson’s various tempos and modes for biological evolution. Next, two historical case studies from the biological sciences are reconstructed to illustrate the robustness of the proposed evolutionary philosophy of science for explicating the progress of the natural sciences. A concluding section discusses the proposed evolutionary philosophy of science with respect to providing a broad-spectrum framework or general philosophy of science for understanding the nature and progress of the natural sciences. (shrink)

This article concerns itself with the reception of Rous’ 1911 discovery of what later came to be known as the Rous Sarcoma Virus. Rous made his discovery at the Rockefeller Institute for Medical Research which had been primarily established to conduct research into infectious diseases. Rous’ chance discovery of a chicken tumor led him to a series of conjectures about cancer causation and about whether cancer could have an extrinsic cause. Rous’ finding was received with some scepticism by the scientific (...) community that held that cancer was not infectious and favored explanations which located the origins of cancer in the inner mechanism of the cell. After 4 years of unsuccessful effort to isolate and further determine the virus Rous felt compelled to discontinue his work on cancer viruses. When 55 years later, the significance of Rous’s discovery was attested by the award of the Nobel Prize, it opened up debates about the issues of delayed recognition and scientific reputation. This article also considers why Rous’ hypothesis of a viral origin of cancer could not be incorporated into the existing body of knowledge about cancer before the 1950s. (shrink)

This paper examines the vital role played by electron microscopy toward the modern definition of viruses, as formulated in the late 1950s. Before the 1930s viruses could neither be visualized by available technologies nor grown in artificial media. As such they were usually identified by their ability to cause diseases in their hosts and defined in such negative terms as “ultramicroscopic” or invisible infectious agents that could not be cultivated outside living cells. The invention of the electron microscope, with magnification (...) and resolution powers several orders of magnitude better than that of optical instruments, opened up possibilities for biological applications. The hitherto invisible viruses lent themselves especially well to investigation with this new instrument. We first offer a historical consideration of the development of the instrument and, more significantly, advances in techniques for preparing and observing specimens that turned the electron microscope into a routine biological tool. We then describe the ways in which the electron microscopic images, or micrographs, functioned as forms of new knowledge about viruses and resulted in a paradigm shift in the very definition of these entities. Micrographs were not mere illustrations since they did the work for the electron microscopists. Drawing extensively on primary publications, we adduce the role of the new instrument in understanding the so-called eclipse phase in virus multiplication and the unexpected spinoffs of data from electron microscopy in naming and classifying viruses. Thus, we show that electron microscopy functioned not only to provide evidence, but also arguments in facilitating a reordering of the world that it brought into the visual realm. (shrink)

Viruses have been virtually absent from philosophy of biology. In this editorial introduction, we explain why we think viruses are philosophically important. We focus on six issues, and we show how they relate to classic questions of philosophy of biology and even general philosophy.

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 examines the successful campaign in Britain to develop canine distemper vaccine between 1922 and 1933. The campaign mobilized disparate groups around the common cause of using modern science to save the nation's dogs from a deadly disease. Spearheaded by landed patricians associated with the country journalThe Field, and funded by dog owners and associations, it relied on collaborations with veterinary professionals, government scientists, the Medical Research Council (MRC) and the commercial pharmaceutical house the Burroughs Wellcome Company (BWC). The (...) social organization of the campaign reveals a number of important, yet previously unexplored, features of interwar science and medicine in Britain. It depended on a patronage system that drew upon a large base of influential benefactors and public subscriptions. Coordinated by theFieldDistemper Fund, this system was characterized by close relationships between landed elites and their social networks with senior science administrators and researchers. Relations between experts and non-experts were crucial, with high levels of public engagement in all aspects of research and vaccine development. At the same time, experimental and commercial research supported under the campaign saw dynamic interactions between animal and human medicine, which shaped the organization of the MRC's research programme and demonstrated the value of close collaboration between veterinary and medical science, with the dog as a shared object and resource. Finally, the campaign made possible the translation of ‘laboratory’ findings into field conditions and commercial products. Rather than a unidirectional process, translation involved negotiations over the very boundaries of the ‘laboratory’ and the ‘field’, and what constituted a viable vaccine. This paper suggests that historians reconsider standard historical accounts of the nature of patronage, the role of animals, and the interests of landed elites in interwar British science and medicine. (shrink)