Melinda Bonnie Fagan

I have previously argued that stem cell experiments cannot demonstrate that a single cell is a stem cell (Fagan 2013a, b). Laplane and others dispute this claim, citing experiments that identify stem cells at the singlecell level. This paper rebuts the counterexample, arguing that the alleged ‘crucial stem cell experiments’ do not measure self-renewal for a single cell, do not establish a single cell’s differentiation potential, and, if interpreted as providing results about single cells, fall into epistemic circularity. I then discuss the source of the dispute, locating it in differences between philosophical and experimental perspectives.

This paper aims to bring the epistemic dimensions of stem cell experiments out of the background, and show that they can be critically evaluated. After introducing some basic concepts of stem cell biology, I set out the current “gold standard” for experimental success in that field (§2). I then trace the origin of this standard to a 1988 controversy over blood stem cells (§3). Understanding the outcome of this controversy requires attention to the details of experimental techniques, the organization of epistemic communities, and relations between the two (§4). With its resolution, a standard for experimental success was established for HSC research, which in turn serves as an exemplar for studies of other stem cells. This historical case study reveals a robust standard for experimental success in stem cell biology: to trace processes of development at the single-cell level, in the form of cell lineage hierarchies. Experiments conforming to this standard can be further critically assessed as means to the therapeutic end of stem cell research: use of stem cells to repair human organs and tissues.

There is a pervasive contrast in the early natural history writings of the co-discoverers of natural selection, Alfred Russel Wallace and Charles Darwin. In his writings from South America and the Malay Archipelago (1848-1852, 1854-1862). Wallace consistently emphasized species and genera, and separated these descriptions from his rarer and briefer discussions of individual organisms. In contrast, Darwin's writings during the Beagle voyage (1831-1836) emphasized individual organisms, and mingled descriptions of individuals and groups. The contrast is explained by the different practices of the two naturalists in the field. Wallace and Darwin went to the field with different educational experiences and social connections, constrained by different responsibilities and theoretical interests. These in turn resulted in different natural history practices; i.e., different habits and working routines in the field. Wallace's intense collecting activities aimed at a complete inventory of different species and their distributions at many localities. Darwin's less intense collecting practice focused on detailed observations of individual organisms. These different practices resulted in different material, textual and conceptual products. Placing natural history practices at the center of analysis reveals connections among these diverse products, and throws light on Wallace and Darwin's respective treatment of individuals and groups in natural history. In particular, this approach clarifies the relation between individuals and groups in Wallace's theory of natural selection, and provides an integrative starting point for further investigations of the broader social factors that shaped Victorian natural history practices and their scientific products.

Philosophy of scientific practice aims to critically evaluate as well as describe scientific inquiry. Epistemic norms are required for such evaluation. Social constructivism is widely thought to oppose this critical project. I argue, however, that one variety of social constructivism, focused on epistemic justification, can be a basis for critical epistemology of scientific practice, while normative accounts that reject this variety of social constructivism cannot., idealized epistemic norms cannot ground effective critique of our practices. I propose a new approach, placing SCj within a general framework of social action theory. This framework can be used to explicate epistemic norms implicit in our scientific practices. *Received July 2009; revised July 2009. †To contact the author, please write to: MS 14, P.O. Box 1892, Houston, TX 77251‐1892; e‐mail: [email protected]

It is widely assumed that mechanistic explanations are causal explanations. Many prominent new mechanists endorse interventionism as the correct analysis of explanatory causal models in biology and other fields. This article argues that interventionism is not entirely satisfactory in this regard. A case study of Jacob and Monod’s operon model shows that at least some important mechanistic explanations in biology present significant contrasts with the interventionist account. This result motivates a more inclusive approach to mechanistic explanation, allowing for noncausal aspects.

Philosophical debates about collective scientific knowledge concern two distinct theses: groups are necessary to produce scientific knowledge, and groups have scientific knowledge in their own right. Thesis has strong support. Groups are required, in many cases of scientific inquiry, to satisfy methodological norms, to develop theoretical concepts, or to validate the results of inquiry as scientific knowledge. So scientific knowledge‐production is collective in at least three respects. However, support for is more equivocal. Though some examples suggest that groups have scientific knowledge independently of their individual members, these cases are also explained in terms of relational complexes of members’ beliefs