Henk de Regt

Currently, a scientific debate is ongoing about modeling nerve impulse propagation. One of the models discussed is the celebrated Hodgkin-Huxley model of the action potential, which is central to the electricity-centered conception of the nerve impulse that dominates contemporary neuroscience. However, this model cannot represent the nerve impulse completely, since it does not take into account non-electrical manifestations of the nerve impulse for which there is ample experimental evidence. As a result, alternative models of nerve impulse propagation have been proposed in contemporary (neuro)scientific literature. One of these models is the Heimburg-Jackson model, according to which the nerve impulse is an electromechanical density pulse in the neural membrane. This model is usually contrasted with the Hodgkin-Huxley model and is supposed to potentially be able to replace the latter. However, instead of contrasting these models of nerve impulse propagation, another approach integrates these models in a general unifying model. This general unifying model, the Engelbrecht model, is developed to unify all relevant manifestations of the nerve impulse and their interaction(s). Here, we want to contribute to the debate about modeling nerve impulse propagation by conceptually analyzing the Engelbrecht model. Combining the results of this conceptual analysis with insights from philosophy of science, we make recommendations for the study of nerve impulse propagation. The first conclusion of this analysis is that attempts to develop models that represent the nerve impulse accurately and completely appear unfeasible. Instead, models are and should be used as tools to study nerve impulse propagation for varying purposes, representing the nerve impulse accurately and completely enough to achieve the specified goals. The second conclusion is that integrating distinct models into a general unifying model that provides a consistent picture of nerve impulse propagation is impossible due to the distinct purposes for which they are developed and the conflicting assumptions these purposes often require. Instead of explaining

It is often claimed—especially by scientific realists—that science provides understanding of the world only if its theories are (at least approximately) true descriptions of reality, in its observable as well as unobservable aspects. This paper critically examines this ‘realist thesis’ concerning understanding. A crucial problem for the realist thesis is that (as study of the history and practice of science reveals) understanding is frequently obtained via theories and models that appear to be highly unrealistic or even completely fictional. So we face the dilemma of either giving up the realist thesis that understanding requires truth, or allowing for the possibility that in many if not all practical cases we do not have scientific understanding. I will argue that the first horn is preferable: the link between understanding and truth can be severed. This becomes a live option if we abandon the traditional view that scientific understanding is a special type of knowledge. While this view implies that understanding must be factive, I avoid this implication by identifying understanding with a skill rather than with knowledge. I will develop the idea that understanding phenomena consists in the ability to use a theory to generate predictions of the target system’s behavior. This implies that the crucial condition for understanding is not truth but intelligibility of the theory, where intelligibility is defined as the value that scientists attribute to the theoretical virtues that facilitate the construction of models of the phenomena. I will show, first, that my account accords with the way practicing scientists conceive of understanding, and second, that it allows for the use of idealized or fictional models and theories in achieving understanding.

This paper approaches the scientific realism question from a naturalistic perspective. On the basis of a historical case study of the work of James Clerk Maxwell and Ludwig Boltzmann on the kinetic theory of gases, it shows that scientists’ views about the epistemological status of theories and models typically interact with their scientific results. Subsequently, the implications of this result for the current realism debate are analysed. The case study supports Giere’s moderately realist view of scientific models and theories, based on the notion of similarity, and it highlights the crucial role of model users. The paper concludes with a discussion of Boltzmann’s Bildtheorie, the sophisticated form of realism that he developed in response to the scientific problems of kinetic theory.

Boltzmann’s Bildtheorie, which asserts that scientific theories are ‘mental pictures’ having at best a partial similarity to reality, was a core element of his philosophy of science. The aim of this article is to draw attention to a neglected aspect of it, namely its significance for the issue of scientific explanation and understanding, regarded by Boltzmann as central goals of science. I argue that, in addition to being an epistemological view of the interpretation of scientific theories Boltzmann’s Bildtheorie has implications for the nature of scientific understanding. This aspect has as yet been ignored because discussion of the Bildtheorie has been restricted to the realism-instrumentalism debate. To elucidate my analysis of Boltzmann’s Bildtheorie concrete examples are presented, and the pragmatist and Darwinist roots of Boltzmann’s view are discussed. Moreover, I propose to use Boltzmann’s ideas as a starting-point for developing a novel analysis of the notion of scientific understanding, of which a brief impression is given. It shows that the study of Boltzmann’s philosophy is not only of historical interest but can be relevant also to modern philosophy of science and to the methodology of theoretical physics.

This article analyses an episode in the earlyhistory of quantum theory: the controversy betweenPauli and Heisenberg about the anomalous Zeemaneffect, which was a main stumbling block for the oldquantum theory of Bohr. It is argued that theindividual philosophical views of both Pauli andHeisenberg directed their attempts to solve theanomaly and decisively influenced the solutions theyproposed. The results of this case study arecompared with the assertions of four theories ofscientific change, namely those of Kuhn, Lakatos,Laudan and Giere.

This book is about scientific understanding. It is widely acknowledged that a central aim of science is to achieve understanding of the world around us, and that possessing such understanding is highly important in our present-day society. But what does it mean to achieve this understanding? What precisely is scientific understanding? These are philosophical questions that have not yet received satisfactory answers. While there has been an ongoing debate about the nature of scientific explanation since Carl Hempel advanced his covering law model in 1948, the related notion of understanding has been largely neglected because most philosophers regarded understanding as merely a subjective byproduct of objective explanations. By contrast, this book puts scientific understanding center stage. It is primarily a philosophical study, but also contains detailed historical case studies of scientific practice. In contrast to most existing studies in this area, it takes into account scientists’ views and analyzes their role in scientific debate and development. The aim of the book is to develop and defend a philosophical theory of scientific understanding that can describe and explain the historical variation of criteria for understanding actually employed by scientists. The theory does justice to the insights of such famous physicists as Werner Heisenberg and Richard Feynman, while bringing much-needed conceptual rigor to their intuitions. The scope of the proposed account of understanding is the natural sciences: while the detailed case studies derive from physics, examples from other sciences are presented to illustrate its wider validity.

TABLE OF CONTENTS
1. Introduction: The desire to understand
2. Understanding and the aims of science
3. Explanatory understanding: A plurality of models
4. A contextual theory of scientific understanding
5. Intelligibility and metaphysics: Understanding gravitation
6. Models and mechanisms: Physical understanding in the nineteenth
7. Visualizability and intelligibility: Insight into the quantum world
8. Conclusion: The many faces of understanding