Mechanisms in Science

by

Carl Craver, Beate Krickel

• LAST REVIEWED: 30 October 2019
• LAST MODIFIED: 30 October 2019
• DOI: 10.1093/obo/9780195396577-0395

Introduction

Many areas of science are animated by the search for mechanisms: experiments are designed to find them, explanations are built to reveal them, models are constructed to describe them, funding is disbursed to prioritize their discovery, and translational research is premised on their value for manipulation and control. Over the last twenty or thirty years, a number of philosophers of science, starting from the biological and neural sciences, have directed attention at the concept of mechanism. They have emphasized that mechanisms play central roles in discovery, explanation, experimentation, modeling, and reduction. At the same time, the idea of mechanism has served for many as a suggestive hint as to the metaphysics of the middle range: covering that domain of phenomena above the size scale of atomic physics and beneath that of planets, encompassing biology, physiology, psychology, and the human and so-called special sciences more generally. What must mechanisms be if they are to play these diverse roles? The term “new mechanism” (to distinguish the modern account from the classical mechanical worldview defended by philosophers such as Descartes or La Mettrie), introduced to describe this research area, runs the risk of homogenizing what has become a heterogeneous body of work, serving many masters and tugging the analysis in many directions at once. Here, we attempt to collect some points of consensus while highlighting areas of productive disagreement and criticism going forward. The authors thank Stuart Glennan and Lindley Darden for feedback on an earlier draft, Sue McKinney for assistance formatting references, and Paola Hernandez-Chavez for support in finding non-English texts.

Central Articles and Books

This section contains central articles and books of notable historical significance within the new mechanism for understanding what the new mechanism sought to achieve and the diverse areas of the philosophy of science in which it was thought to do useful service. Bechtel and Richardson 1993 sketches a road map (or decision-tree) that researchers face in the search for mechanisms. The authors focus specifically on the effort to decompose complex functions into subfunctions, and to localize those subfunctions to different locations in a system, such as a cell or a body. These strategies, they point out, make sense against the background idea that the scientists aim, in their research, to discover mechanisms. Bechtel and Abrahamsen 2005 extends this work to offer a mechanistic theory of explanation opposed to the idea that explanations require knowing the laws of nature. Glennan 1996 also deploys the concept of mechanism, but in the service of a philosophical analysis of causation. For Glennan, mechanisms are the hidden connection Hume sought between a cause and its effect. He has subsequently refined and revised his views in light of criticism and theory development (see Glennan 2002 for contrasts with Salmon’s mechanistic view; see also Glennan 2017 for its latest development, emphasizing nominalism and an activities-based view of causation). Machamer, Darden, and Craver (commonly known as MDC) were less concerned with a particular set of research strategies and with Hume’s search for a hidden connection between cause and effect than they were with the suggestion that attention to mechanisms could revolutionize the philosophy of science, transforming discussions of causation, discovery, functions, laws, levels, and reduction. They characterize mechanisms as entities and activities organized in the production of regular changes from start or set-up conditions to finish and termination conditions, and they argue that the drive to satisfy this explanatory demand shapes the practice of the biological and neural sciences (see Machamer, et al. 2000). Following this publication, Darden pursued the issue of mechanism discovery, both alone and in cooperation with Craver and others. Key papers in this development are compiled in Darden 2006. Darden’s view perhaps has its fullest development in Craver and Darden 2013. Craver, in contrast, began to work on the relevance of mechanism to the topic of scientific explanation. In Craver 2001 he explores how Cummins’ idea of an analytic account of functional explanation applies to the multilevel mechanistic theories of the physiological sciences. His most systematic treatment of the topic can be found in Craver 2007, which became a focus of much subsequent discussion.

• Bechtel, William, and Adele Abrahamsen. “Explanation: A Mechanist Alternative.” In Special Issue: Mechanisms in Biology. Edited by Carl F. Craver and Lindley Darden. Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 36.2 (2005): 421–441.

  DOI: 10.1016/j.shpsc.2005.03.010

  Bechtel and Abrahamsen set the grounds for the epistemic interpretation of mechanisms as explanatory models. They discuss the benefits of this view over law-based accounts of explanation.

• Bechtel, William, and Robert C. Richardson. Discovering Complexity: Decomposition and Localization as Strategies in Scientific Research. Princeton, NJ: Princeton University Press, 1993.

  Analyzes the heuristics of decomposition and localization that are crucial for the discovery of mechanisms and in the development of mechanistic models in cell biology, cognitive neuroscience, and genetics.

• Craver, Carl F. “Role Functions, Mechanisms and Hierarchy.” Philosophy of Science 68 (2001): 31–55.

  DOI: 10.1086/392866

  Craver unifies Cummins’ view of functions with his multilevel mechanistic picture of explanation (Cummins 1975), arguing that contextual role functions constitute a third aspect of causal-mechanical explanation, beyond etiological and constitutive.

• Craver, Carl F. Explaining the Brain: Mechanisms and the Mosaic Unity of Neuroscience. New York: Oxford University Press, 2007.

  DOI: 10.1093/acprof:oso/9780199299317.001.0001

  Discusses the nature of explanations in neuroscience and defends the view that good neuroscientific explanations are descriptions of multilevel mechanisms.

• Craver, Carl F., and Lindley Darden. In Search of Mechanisms: Discoveries across the Life Sciences. Chicago: University of Chicago Press, 2013.

  DOI: 10.7208/chicago/9780226039824.001.0001

  Explains the relevance of mechanism to discovery, with detailed examples and case-studies from the history of biology and contemporary biology, including the neural sciences. Details stages of mechanism discovery and strategies for solving specific discovery problems.

• Darden, Lindley. Reasoning in Biological Discoveries: Essays on Mechanism, Interfield Relations, and Anomaly Resolution. New York: Cambridge University Press, 2006.

  DOI: 10.1017/CBO9780511498442

  Contains many of Darden’s papers, alone and with coauthors, on how the search for mechanisms constrains scientific discovery, in addition to Darden’s earlier work on interfield theories and an anomaly-driven theory change.

• Glennan, Stuart. “Mechanisms and the Nature of Causation.” Erkenntnis 44 (1996): 49–71.

  DOI: 10.1007/BF00172853

  Proposes a mechanistic theory of causation according to which A and B causally interact only if there is a mechanism between them.

• Glennan, Stuart. “Rethinking Mechanistic Explanation.” Philosophy of Science 69.S3 (2002): S342–S353.

  DOI: 10.1086/341857

  Develops Glennan’s complex system view of mechanisms and contrasts it with Wesley Salmon’s and Peter Railton’s accounts.

• Glennan, Stuart. The New Mechanical Philosophy. Oxford: Oxford University Press, 2017.

  DOI: 10.1093/oso/9780198779711.001.0001

  See especially Glennan’s discussion in chapter 2 of the many ways of solving problems of both defining and demarcating mechanisms.

• Machamer, Peter, Lindley Darden, and Carl F. Craver. “Thinking About Mechanisms.” Philosophy of Science 67.1 (2000): 1–25.

  DOI: 10.1086/392759

  This is probably the most prominent article of the new mechanistic literature. It provides starting points for many discussions, such as how to characterize mechanisms and how to describe the relationship between mechanisms and mechanistic explanation and the role of mechanisms in discovery.