The Philosophy and History of Molecular Biology: New Perspectives

The volume’s title announces a series of studies in the history and philosophy of molecular biology. In fact, however, rather than a mere collection of case studies, it proposes a stimulating, multilevel reflection on the topic “What is molecular biology?” For Doris Zallen, molecular biology includes studies of phenomena on the molecular level, using simple models, techniques borrowed from the physical sciences, and mathematical models. This definition allows her to call attention to the fact that other areas of biological study, such as bioenergetics, can also be called “molecular biology.”

Why, then, do official histories of molecular biology not include bioenergetics? One answer may be sociological: a group of scientists who first proclaimed themselves “molecular biologists” and aggressively promoted what they presented as an innovative approach, keeping competitors who wanted to join a success story at bay. Another answer may be technical and instrumental: Lily Kay proposes that molecular biology was concerned with macromolecules, with a specific submicroscopic level of explanation, with instruments (such as the electron microscope or the ultracentrifuge) specifically designed to study macromolecules, and with the organization of large team projects around these instruments, aimed at the specific goal of controlling life. Bioenergetics does not fit in this definition, because it was not primarily concerned with macromolecules, it employed a different set of instruments and techniques, and it had other aims.

According to Kay, molecular biology deals exclusively with upward mechanisms of causation (from simple events to more complicated ones) and neglects completely the explanatory role of downward causation, central for development studies. Scott Gilbert argues, however, that development studies successfully “assimilated” selected molecular biology approaches: the lac operon model developed by Jacob and Monod was presented as the victory of embryology, a discipline that stresses complexity and environmental effects, over the narrow genetic approach, interested exclusively in genes. With this model, molecular biology was able to explain how nongenetic phenomena affect what genes actually do. Immunology also became molecular, but, as Alfred Tauber explains, not through the “assimilation” of molecular biology approaches, but rather through narrowing its scope of inquiry. Only phenomena that can be fully molecularized were defined as “properly immunological” (p. 156).

In parallel, Sahotra Sarkar stresses the limitation imposed on biological knowledge when attention is paid exclusively to inheritance patterns in which DNA is completely isolated from the soma and can be studied by reductionist methods of classical genetics. David Thaler disagrees: for him, the perception of “classical genetics” as an exclusively reductionist approach is incorrect, for this discipline was also concerned with levels of interaction between phenomena. Thaler, Sarkar, and Kenneth Schaffner (and, to some degree, Gilbert and Tauber) focus on the role of concepts in the development of molecular biology. Richard Burian questions this focus from the philosopher’s point of view. For him, molecular biology is an immense battery of techniques without a central unifying theory, and precisely for this reason it is less reductionist and more adaptable to different settings than was biochemistry. This characteristic of molecular biology affects the nature of philosophical explanations: theory-centered philosophical analysis must be wrong, at least for this science.

The answers to the question “What is molecular biology?” provided in this volume are far from uniform. One may argue that such heterogeneity of opinions faithfully reflects the uncertainty concerning the definition of molecular biology—at least for the reflective scientist, the historian, and the philosopher. By contrast, heads of departments of molecular of biology, popularizers of science, and industrialists seem to agree about the nature and the uses of molecular biology. How such agreement was achieved may be a fitting subject for a different volume.