Melinda Bonnie Fagan

Stem cells are defined as having capacities for both self-renewal and differentiation. Many different entities satisfy this working definition. I show that this general stem cell concept is relative to a cell lineage, temporal duration, and characters of interest. Experiments specify values for these variables. So claims about stem cells must be understood in terms of experimental methods used to identify them. Furthermore, the stem cell concept imposes evidential constraints on interpretation of experimental results. From these constraints, it follows that claims about stem cell capacities are inherently uncertain. This result has important implications for stem cell research

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

Evolutionary systems biology (ESB) aims to integrate methods from systems biology and evolutionary biology to go beyond the current limitations in both fields. This article clarifies some conceptual difficulties of this integration project, and shows how they can be overcome. The main challenge we consider involves the integration of evolutionary biology with developmental dynamics, illustrated with two examples. First, we examine historical tensions between efforts to define general evolutionary principles and articulation of detailed mechanistic explanations of specific traits. Next, these tensions are further clarified by considering a recent case from another field focused on developmental dynamics: stem cell biology. In the stem cell case, incompatible explanatory aims block integration. Experimental approaches aim at mechanistic explanation while dynamical system models offer explanation in terms of general principles. We then discuss an ESB case in which integration succeeds: search for general attractors using a dynamical systems framework synergizes with the experimental search for detailed mechanisms. Contrasts between the positive and negative cases suggest general lessons for achieving an integrated understanding of developmental and evolutionary dynamics. The key integrative move is to acknowledge two complementary aims, both relevant to explanation: identifying the space of possible dynamic states and trajectories, and mechanistic understanding of causal interactions underlying a specific phenomenon of interest. These two aims can support one another in a joint project characterizing dynamic aspects of evolving lineages. This more inclusive project can lead to insights that cannot be reached by either approach in isolation.

Stem cell biology is driven by experiment. Its major achievements are striking experimental productions: "immortal" human cell lines from spare embryos (Thomson et al. 1998); embryo-like cells from "reprogrammed" adult skin cells (Takahashi and Yamanaka 2006); muscle, blood and nerve tissue generated from stem cells in culture (Lanza et al. 2009, and references therein). Well-confirmed theories are not so prominent, though stem cell biologists do propose and test hypotheses at a profligate rate. 1 This paper aims to characterize the role of experiment in stem cell biology, so as to answer the following question: how do experiments contribute to our knowledge of stem cells and related phenomena? The ..

If there is collective scientific knowledge, then at least some scientific groups have beliefs over and above the personal beliefs of their members. Gilbert's plural-subjects theory makes precise the notion of ‘over and above’ here. Some philosophers have used plural-subjects theory to argue that philosophical, historical and sociological studies of science should take account of collective beliefs of scientific groups. Their claims rest on the premise that our best explanations of scientific change include these collective beliefs. I argue that Gilbert's account of collective scientific belief does not provide a better explanation of scientific change than a non-collective alternative. A different defence of collective scientific belief and knowledge is needed

Philosophical understanding of experimental scientific practice is impeded by disciplinary differences, notably that between philosophy and sociology of science. Severing the two limits the stock of philosophical case studies to narrowly circumscribed experimental episodes, centered on individual scientists or technologies. The complex relations between scientists and society that permeate experimental research are left unexamined. In consequence, experimental fields rich in social interactions have received only patchy attention from philosophers of science. This paper sketches a remedy for both the symptom and its root cause. An empirical study of social interactions in an established field of biomedicine grounds a robust account of success in experimental practice. The core idea is the concept of collaboration, of participants working together on a common project toward a shared goal. The interactive social integument of experimental research is both examined and enacted in a study integrating socio-historical research and philosophical investigation. The two approaches are used in concert to explicate the concept of scientific objectivity. Their joint explication of this contested epistemic ideal demonstrates that philosophical and sociological approaches can work together toward a social epistemology of scientific practice. The explication is in three stages. First, a minimal framework for investigating collaborative activities is established. Social action is understood and evaluated in terms of the connection between shared goals that participants hope to accomplish together, and the coordinated means by which they try to do so. This connection is explicated as participation, a relation mediating between a group and its members, which includes minimal constraints of instrumental rationality. Second, this framework is fleshed out via empirical study of scientific practices. The focal case examines the intersection of immunology and stem cell research in mid-20th century biomedicine, tracing the key social interactions within and among laboratory groups, as the field of blood stem cell research emerged in the 1960s and advanced throughout the next four decades. The study yields a robust empirical result. Participants consistently recognize two aspects of scientific success: construction of improved models of blood cell development, and formation of new boundaries among scientific groups. In the third and final stage, this result is generalized to other experimental episodes and shown to fit with recent accounts of models in scientific practice. The generalized result approximates a familiar normative view of scientific knowledge. An epistemic ideal of scientific objectivity in practice is then derived from this robust general result, using the minimal constraints on rational participation. The derivation is analogous to specification of ends in moral philosophy; given the means taken and assuming some hope of success, what must the goal of scientific inquiry be like? The aim of science so conceived corresponds to a classic conception of scientific objectivity: knowledge independent of epistemic criteria specific to particular persons or groups. This result weaves together sociological and philosophical accounts of science, explicating the epistemic ideal of objectivity in relation to social aspects of scientific practice. This undercuts the entrenched dualism between normative, vs. descriptive approaches to scientific knowledge. Socio-historical study of science does not deflate, but vindicates, scientific objectivity. Philosophy and sociology are recast as collaborating participants in articulating social epistemology of science

Epistemology of science is currently polarized. Descriptive accounts of the social aspects of science coexist uneasily with normative accounts of scientific knowledge. This tension leads students of science to privilege one of these important aspects over the other. I use an episode of recent immunology research to develop an integrative account of scientific inquiry that resolves the tension between sociality and epistemic success. The search for the hematopoietic stem cell by members of Irving Weissman’s laboratory at Stanford University Medical Center exhibits both the goal-oriented character of contemporary immunology and the importance of social interactions in successful achievement of those goals. This episode includes three kinds of epistemic success: characterization of HSC, formation of new interdisciplinary interfaces, and reconciliation of apparently incompatible models. All three depend on coordinating the work of diverse participants via social interactions. Together, they reveal the crucial role of social interactions within and between research groups in producing epistemic success. These features of the search for the HSC generalize to immunology as a whole, and plausibly to other disciplines. This account thus resolves the polarizing tension in epistemology of science, and complements individualistic accounts of scientific knowledge and rationality

This essay examines the role of social interactions in the search for blood stem cells, in a recent episode of biomedical research. Linked to mid-20th century cell biology, genetics and radiation research, the search for blood stem cells coalesced in the 1960s and took a developmental turn in the late 1980s, with significant ramifications for immunology, stem cell and cancer biology. Like much contemporary biomedical research, this line of inquiry exhibits a complex social structure and includes several prominent scientific successes, recognized as such by participating researchers. I use personal interviews and the published record to trace the social interactions crucial for scientific success in this episode. All recognized successes in this episode have two aspects: improved models of blood cell development, and new interfaces with other lines of research. The narrative of the search for blood stem cells thus yields a robust account of scientific success in practice, which generalizes to other scientific episodes and lends itself to expansion to include wider social contexts