This paper addresses the recent resurgence of Nagel style reduction in the philosophical literature. In particular, it considers the so-called multiple realizability objection to reductionism presented most forcefully by Sober in 1999. It is argued that this objection misses the point of multiple realizability and that there remain serious problems for reductionist methodologies in science.
Joint paper with Collin Rice, forthcoming in Philosophy of Science.
This paper discusses minimal model explanations, which we argue are distinct from various causal, mechanical, difference making, etc., strategies prominent in the philosophical literature. We contend that what accounts for the explana- tory power of these models is not that they have certain features in common with real systems. Rather, the models are explanatory because of a story about why a class of systems will all display the same large-scale behavior because the details that distinguish them are irrelevant. This story explains patterns across extremely diverse systems and shows how minimal models can be used to understand real systems.
Bridging Across Scales: Emergence and Effective Theories
Robert Batterman, Principal Investigator
May 1, 2013 - October 31, 2015
This project addresses the problem of modeling behaviors of systems at widely separated scales. Top-down, continuum modeling is safe and successful. Bottom-up atomic scale modeling is also appropriate and necessary. However, questions arise about why the continuum strategies are safe and successful and about how they relate to bottom-up atomic scale strategies. What explains the relative autonomy of continuum modeling? This autonomy is, we believe, a key feature of emergence. These questions are intimately connected with understanding how effective (field) theories are constructed and how they characterize emergent phenomena. Similar questions arise in new work on synthesis at the nanoscale. The construction of nanoparticles with specific properties involve attempts to fit atomic lattice properties with nanoscale features that often require continuum-like concepts such as surfaces and boundaries. The aim is to understand emergence and the relative autonomy of emergent effective theories in terms of mixed scale methods. These methods, involving homogenization theory and renormalization group theory, allow for a sophisticated and precise understanding of phenomena and theories that have been characterized, sometimes rather uncritically, using the term "emergent". The project is important because the term "emergent" is employed in various incompatible ways. This has led to considerable confusion. By focusing on the means for explaining the autonomy and safety of various modeling strategies and theories that characterize systems at relatively large scales, the project will settle a number of philosophical questions relating to issues about emergence and reduction. Specific activities include workshops and a conference bringing together applied mathematicians, physicists, and philosophers.
Mark Wilson, University of Pittsburgh
Christopher Smeenk, University of Western Ontario
The Oxford Handbook of Philosophy of Physics, Oxford University Press (New York), 2013.
This Oxford Handbook provides an overview of many of the topics that currently engage philosophers of physics. It surveys new issues and the problems that have become a focus of attention in recent years. It also provides up-to-date discussions of the still very important problems that dominated the field in the past.
In the late 20th Century, the philosophy of physics was largely focused on orthodox Quantum Mechanics and Relativity Theory. The measurement problem, the question of the possibility of hidden variables, and the nature of quantum locality dominated the literature on the quantum mechanics, whereas questions about relationalism vs. substantivalism, and issues about underdetermination of theories dominated the literature on spacetime. These issues still receive considerable attention from philosophers, but many have shifted their attentions to other questions related to quantum mechanics and to spacetime theories. Quantum field theory has become a major focus, particularly from the point of view of algebraic foundations. Concurrent with these trends, there has been a focus on understanding gauge invariance and symmetries.
The philosophy of physics has evolved even further in recent years with attention being paid to theories that, for the most part, were largely ignored in the past. For example, the relationship between thermodynamics and statistical mechanics---once thought to be a paradigm instance of unproblematic theory reduction---is now a hotly debated topic. The implicit, and sometimes explicit, reductionist methodology of both philosophers and physicists has been severely criticized and attention has now turned to the explanatory and descriptive roles of "non-fundamental,'' phenomenological theories. This shift of attention includes "old'' theories such as classical mechanics, once deemed to be of little philosophical interest. Furthermore, some philosophers have become more interested in "less fundamental'' contemporary physics such as condensed matter theory. Questions abound with implications for the nature of models, idealizations, and explanation in physics. This Handbook showcases all these aspects of this complex and dynamic discipline.