Kenneth Schaffner

This article considers claims that biology should seek general theories similar to those found in physics but argues for an alternative framework for biological theories as collections of prototypical interlevel models that can be extrapolated by analogy to different organisms. This position is exemplified in the development of the Hodgkin‐Huxley giant squid model for action potentials, which uses equations in specialized ways. This model is viewed as an “emergent unifier.” Such unifiers, which require various simplifications, involve the types of heuristics discussed in Wimsatt’s writings on reduction, but with a twist. Here, the heuristics are used to generate emergent rather than reductive explanations. †To contact the author, please write to: Department of History and Philosophy of Science, University of Pittsburgh, 1017 Cathedral of Learning, Pittsburgh, PA 15260; e‐mail: [email protected].

In this paper, I propose two theses, and then examine what the consequences of those theses are for discussions of reduction and emergence. The first thesis is that what have traditionally been seen as robust, reductions of one theory or one branch of science by another more fundamental one are a largely a myth. Although there are such reductions in the physical sciences, they are quite rare, and depend on special requirements. In the biological sciences, these prima facie sweeping reductions fade away, like the body of the famous Cheshire cat, leaving only a smile.... The second thesis is that the "smiles" are fragmentary patchy explanations, and though patchy and fragmentary, they are very important, potentially Nobel-prize winning advances. To get the best grasp of these "smiles," I want to argue that, we need to return to the roots of discussions and analyses of scientific explanation more generally, and not focus mainly on reduction models, though three conditions based on earlier reduction models are retained in the present analysis. I briefly review the scientific explanation literature as it relates to reduction, and then offer my account of explanation. The account of scientific explanation I present is one I have discussed before, but in this paper I try to simplify it, and characterize it as involving field elements and a preferred causal model system abbreviated as FE and PCMS. In an important sense, this FE and PCMS analysis locates an "explanation" in a typical scientific research article. This FE and PCMS account is illustrated using a recent set of neurogenetic papers on two kinds of worm foraging behaviors: solitary and social feeding. One of the preferred model systems from a 2002 Nature article in this set is used to exemplify the FE and PCMS analysis, which is shown to have both reductive and nonreductive aspects. The paper closes with a brief discussion of how this FE and PCMS approach differs from and is congruent with Bickle's "ruthless reductionism" and the recently revived mechanistic philosophy of science of Machamer, Darden, and Craver.

Caenorhabditis elegans is a tiny worm that has become the focus of a large number of worldwide research projects examining its genetics, development, neuroscience, and behavior. Recently several groups of investigators have begun to tie together the behavior of the organism and the underlying genes, neural circuits, and molecular processes implemented in those circuits. Behavior is quintessentially organismal—it is the organism as a whole that moves and mates—but the explanations are devised at the molecular and neurocircuit levels, and tested in populations using protocols that span many levels of aggregation. Following a brief review of the main relevant features of C. elegans, I describe some of these circuits, and then discuss two contrasting approaches in behavioral genetics and neural network analysis of the worm. Finally, I outline the rudiments of a “field and focus” explanation model using the two contrasting approaches.

In this rejoinder to the three preceding comments, I provide some additional philosophical warrant for the biomedical sciences' focus on model organisms. I then relate the inquiries on model systems to the concept of 'deep homology', and indicate that the issues that appear to divide my commentators and myself are in part empirical ones. I cite recent work on model organisms, and especially C. elegans that supports my views. Finally, I briefly readdress some of the issues raised by Developmental Systems Theory

This article examines how a molecular "solution" to an important biological problem-how is antibody diversity generated? was obtained in the 1970s. After the primarily biological clonal selection theory (CST) was accepted by 1967, immunologists developed several different contrasting theories to complete the SCST. To choose among these theories, immunology had to turn to the new molecular biology, first to nucleic acid hybridization and then to recombinant DNA technology. The research programs of Tonegawa and Leder that led to the "solution" are discussed, and some of their strategies and heuristics are broadly characterized: (1) to what extent does the new recombinant DNA technology provide what the scientists claim is "direct evidence," what does that term mean, and what are the implications of that claim for biological "realism," and (2) is this episode one of reduction, partial reduction, or explanatory extension, and what do these terms mean in the context of a successful molecular "solution" to a biological problem.

This paper examines the nature of theory structure in biology and considers the implications of those theoretical structures for theory reduction. An account of biological theories as interlevel prototypes embodying causal sequences, and related to each other by strong analogies, is presented, and examples from the neurosciences are provided to illustrate these middle-range theories. I then go on to discuss several modifications of Nagel''s classical model of theory reduction, and indicate at what stages in the development of reductions these models might best apply. Finally I consider several implications of these analyses of theory structure and reduction for disciplinary integration in biology.

This two-part article examines the competition between the clonal selection theory and the instructive theory of the immune response from 1957–1967. In Part I the concept of a temporally extended theory is introduced, which requires attention to the hitherto largely ignored issue of theory individuation. Factors which influence the acceptability of such an extended theory at different temporal points are also embedded in a Bayesian framework, which is shown to provide a rational account of belief change in science. In Part II these factors, as elaborated in the Bayesian framework, are applied to the case of the success of the clonal selection theory and the failure of the instructive theory.

Caenorhabditis elegans (C. elegans) is a tiny worm that has become the focus of a large number of worldwide research projects examining its genetics, development, neuroscience, and behavior. Recently several groups of investigators have begun to tie together the behavior of the organism and the underlying genes, neural circuits, and molecular processes implemented in those circuits. Behavior is quintessentially organismal--it is the organism as a whole that moves and mates--but the explanations are devised at the molecular and neurocircuit levels, and tested in populations using protocols that span many levels of aggregation. Following a brief review of the main relevant features of C. elegans, I describe some of these circuits, and then discuss two contrasting approaches in behavioral genetics and neural network analysis of the worm. Finally, I outline the rudiments of a "field and focus" explanation model using the two contrasting approaches

Assessing the normative status of concepts of health and disease involves one in questions regarding the relationship between fact and value. Some have argued that Christopher Boorse's conception of health and disease lacks such a valuational element because it cannot account for types of harms which, while disvalued, do not have evolutionarily dysfunctional consequences. I take Boorse's account and incorporate some Humean-like sociobiological assumptions in order to respond to this challenge. The possession of moral sentiments, I argue, offers an evolutionary advantage (thus falling within Boorse's definition of normal functional abilities). However, this does not amount to emotivism: on the contrary, these sentiments can be the basis of a value system. This value structure introduces the concept of sympathizing with a fellow being's suffering as the basis of a normative dimension to disease. For example, it holds the disvalue of disease to lie in the fact that disease involves suffering and functional limitations.The naturalistic Humean type of account presented here thus jumps the normative-descriptive divide. When Boorse's account is extended to include social sentiments and behaviors, a conception of health emerges which is broader than Boorse's or Kass's, but narrower than the WHO's.

the structure of medical science with a special focus on the role of generalizations and universals in medicine, and (2) philosophy of medicine's relation with the philosophy of science. I argue that a usually overlooked aspect of Kuhnian paradigms, namely, their characteristic of being "exemplars", is of considerable significance in the biomedical sciences. This significance rests on certain important differences from the physical sciences in the nature of theories in the basic and the clinical medical sciences. I describe those differences and maintain that they are these differentiating features that require the use of more comparative and analogical reasoning in medicine. I suggest that Kitcher's recent introduction of the notion of a ‘practice’ may have similar implications if it is construed to contain more analogical elements than he appears to recognize in his initial formulation. Finally I argue that though Gorovitz and MacIntyre's characterization of medicine as a "science of particulars" bears some similarities with my thesis, I maintain that such a position without careful qualification can lead to ignoring both the nature of generalizations in these sciences and their role as positive analogies tying together a family of overlapping models. Keywords: medical reasoning, biomedical theories/paradigms, science of particulars, philosophy of medicine CiteULike Connotea Del.icio.us What's this?