Yoshinari Yoshida

Plasticity of living systems has long attracted life scientists in different fields, but a detailed philosophical analysis of the very concept has yet to be undertaken. Antonine Nicoglou’s Plasticity in the Life Sciences addresses this problem. By combining a historical examination of the concept of plasticity from Aristotle to contemporary biology and philosophical analysis of its status and roles in biological research, the book provides a rich picture of plasticity as a “boundary concept.” It is also a great example of a highly integrated historical and philosophical inquiry into a scientific concept.

Many philosophers have explored the extensive use of non-universal generalizations in different sciences for inductive and explanatory purposes, analyzing properties such as how widely a generalization holds in space and time. In the present paper, we concentrate on developmental biology to distinguish and characterize two common approaches to scientific generalization—mechanism generalization and principle generalization. The former approach seeks detailed descriptions of causal relationships among specific types of biological entities that produce a characteristic phenomenon across some range of different biological entities; the latter approach abstractly describes relations or interactions that occur during ontogeny and are exemplified in a wide variety of different biological entities. These two approaches to generalization correspond to different investigative aims. Our analysis shows why each approach is sought in a research context, thereby accounting for how practices of inquiry are structured. It also diagnoses problematic assumptions in prior discussions, such as abstraction always being correlated positively with generalizations of wide scope.

How do biologists pursue generalizations given the heterogeneity of biological systems? This paper addresses this question by examining an aspect of scientific generalization that has received little philosophical attention: how scientists _express_ generalizations. Although it is commonly assumed that a scientific generalization takes the form of a representation referring to a property that is shared across a range of things, scientists sometimes express their ideas about generality by displaying multiple representations in certain configurations. Such configurations highlight commonalities between different target systems without eliminating system-specific differences. I analyze visual representations in review articles about collective cell migration as a case study. This illustrates that different types of visualizations, including single diagrams and configurations of multiple representations, function in a complementary way to promote understanding of, and reasoning about, generality, specificity, and diversity of biological mechanisms. I also discuss roles of generalizations in scientific investigations more broadly. I argue that an important role of generalizations in scientific research is to mediate and facilitate cross-fertilization among studies of different target systems. Multiple generalizations in research on collective cell migration together provide perspectives from which different biological systems are characterized and compared. They also provide heuristic hypotheses for studying less-explored systems as well as a basis for comparing developmental, pathological, and regenerative processes. This study sheds new light on how scientists pursue generalizations while embracing system-specific details. It also suggests that philosophical discussions should pay more attention to not only what representations scientists construct, but also how they present such representations.

Biologists often study particular biological systems as models of a phenomenon of interest even if they already know that the phenomenon is produced by diverse mechanisms and hence none of those systems alone can sufficiently represent it. To understand this modeling practice, the present paper provides an account of how multiple model systems can be used to study a phenomenon that is produced by diverse mechanisms. Even if generalizability of results from a single model system is significantly limited, generalizations concerning specific aspects of mechanisms often hold across certain ranges of biological systems, which enables multiple model systems to jointly represent such a phenomenon. Comparing mechanisms that operate in different biological systems as examples of the same phenomenon also facilitates characterization and investigation of individual mechanisms. I also compare my account with two existing accounts of the use of multiple model systems and argue that my account is distinct from and complementary to them.

Although there are many historical and philosophical analyses of evolutionary developmental biology (EvoDevo), its development in the 1980s, when many individual or collective attempts to synthesize evolution and development were made, has not been examined in detail. This article focuses on some interdisciplinary studies during the 1980s and argues that they had important characteristics that previous historical and philosophical work has not recognized. First, we clarify how each set of studies from the 1980s integrated the results or approaches from different biological fields, such as paleontology, developmental genetics, comparative morphology, experimental embryology, theoretical developmental biology, and population genetics. Second, after close examination we show that the interdisciplinary studies during the 1980s adopted different and conflicting views of genes, such as developmental-genetic, epigenetic, or population-genetic ones. We conclude that EvoDevo in the 1980s was a motley aggregation of various kinds of local integration. Finally, we discuss the implications of our analysis by comparing these early EvoDevo studies with those of the Modern Synthesis and with the present state of EvoDevo.