Elisabeth Lloyd

Climate scientists have been engaged in a decades-long debate over the standing of satellite measurements of the temperature trends of the atmosphere above the surface of the earth. This is especially significant because skeptics of global warming and the greenhouse effect have utilized this debate to spread doubt about global climate models used to predict future states of climate. I use this case from an understudied science to illustrate two distinct philosophical approaches to the relations among data, scientist, measurement, models, and theory. I argue that distinguishing between “direct” empiricist and “complex” empiricist approaches helps us understand and analyze this important scientific episode. I introduce a complex empiricist account of testing and evaluation, and contrast it with the basic hypothetico-deductive approach to the climate models used by the direct empiricists. This more developed complex empiricist approach will serve philosophy of science well, as computational models become more widespread in the sciences.

Modern science’s ability to produce, store, and analyze big datasets is changing the way that scientific research is practiced. Philosophers have only begun to comprehend the changed nature of scientific reasoning in this age of “big data.” We analyze data-focused practices in biology and climate modeling, identifying distinct species of data-centric science: phenomena-laden in biology and phenomena-agnostic in climate modeling, each better suited for its own domain of application, though each entail trade-offs. We argue that data-centric practices in science are not monolithic because the opportunities and challenges presented by big data vary across scientific domains.

In this paper we consider some questions surrounding whether or not regional climate models “add value,” a controversial issue in climate science today. We highlight some objections frequently made about regional climate models both within and outside the community of modelers, including several claims that regional climate models do not “add value.” We show that there are a number of issues involved in the latter claims, the primary ones centering on the fact that different research questions are being pursued by the modelers making the complaints against regional climate models. Further issues focus on historical deficiencies of particular—but not generalizable—failures of individual regional models. We provide tools to sort out these different research questions and particular failures, and to improve communication and understanding surrounding added value in climate modeling and philosophy of climate science.

Natural selection causes adaptation, the fit between an organism and its environment. For example, the white and grey coloration of snowy owls living and breeding around the Arctic Circle provides camouflage from both predators and prey. In this Element, we explore a variety of such outcomes of the evolutionary process, including both adaptations and alternatives to adaptations, such as nonadaptive traits inherited from ancestors. We also explore how the concept of adaptation is used in evolutionary psychology and in animal behavior, and the adequacy of methods used to confirm evolutionary accounts of human traits and behaviors.

Since the fundamental challenge that I laid at the doorstep of the pluralists was to defend, with nonderivative models, a strong notion of genic cause, it is fatal that Waters has failed to meet that challenge. Waters agrees with me that there is only a single cause operating in these models, but he argues for a notion of causal ‘parsing’ to sustain the viability of some form of pluralism. Waters and his colleagues have some very interesting and important ideas about the sciences, involving pluralism and parsing or partitioning causes, but they are ideas in search of an example. He thinks he has found an example in the case of hierarchical and genic selection. I think he has not.

As we advance into the twenty-first century, the evidence of climate change is all around us. In the introduction to this volume, we discuss some of the successes of climate science in understanding and attributing the causes of these changes, as well as some of the challenges it faces in addressing questions for which we do not yet have the answers. We focus on the role of climate models and the philosophical and conceptual problems facing climate modelers and climate modeling. We then give the reader an outline of what they will find in each of the 15 Chapters in the volume. The book is divided into three major parts: Part 1 “Confirmation and Evidence”; Part 2 “Uncertainties and Robustness”; and Part 3 “Climate Models as Guides to Policy”.

In this brief chapter, Lloyd sets the stage for the following three papers, most centrally, Santer et al., which discusses whether the satellite data fit with climate models. Its target is a paper by Douglass et al., which claimed that satellite and weather balloon data showed that the climate models were wrong and could not be trusted. The Santer and Wigley “Fact Sheet” gives a nontechnical summary of what is wrong with the Douglass paper, while the full story is in Chap. 5, a reprint of the Santer et al. paper. The context and import of this work is discussed in Lloyd. In this introduction, Lloyd emphasizes the timeliness of this work, as climate deniers testify in Congress presently.

The conflation of two fundamentally distinct issues has generated serious confusion in the philosophical and biological literature concerning the units of selection. The questions of how a unit of selection is defined, theoretically, is rarely distinguished from the question of how to determine the empirical accuracy of claims--either specific or general--concerning which unit(s) are undergoing selection processes. In this paper, I begin by refining a definition of the unit of selection, first presented by William Wimsatt, that is grounded in the structure of natural selection models. I then explore the implications of this definition for empirical evaluation of group selection models. I examine an objection to Wimsatt’s definition raised by Elliott Sober, and I conclude by indicating how the proposed refined definition can clarify which sorts of empirical evidence could be brought to bear on group selection controversies.

The structure of evolutionary theory has proved difficult to characterize. Most available analyses focus on the existence of evolutionary laws and on the axiomatizability of the theory; such analyses pay insufficient attention to mathematical evolutionary models and their structure, and to the structural complications arising from the variety of evolutionary sub-theories. ;The primary goal of this dissertation is to introduce and develop an analysis of the structure of evolutionary theory that is both precise and useful. The secondary goal is to offer further evidence of the appropriateness and utility of the semantic view of theories, as developed by P. Suppes, B. C. van Fraassen, and F. Suppe, in which the theory is viewed as a family of related mathematical models. ;After reviewing the semantic approach, I provide a formal framework for describing and distinguishing among population genetics models. The interrelations among the models are described through a set of notions developed and made precise through the analysis of several evolutionary sub-theories, including genic selection and species selection. The framework of model specification, combined with the notions describing formal relations among models, are offered as a system capable of describing any part or aspect of the structure of evolutionary theory. ;Finally, I present a view of confirmation that relies on the distinctions present in the above system of theory description. I argue that this view of confirmation has two advantages over a hypothetico-deductive view of confirmation. First, it is possible to establish the reasonableness of viewing a variety of evidence as a form of confirmation. Second, as I show in the analysis of a controversial model, distinctions can be made due to the subtlety of the view that do not appear under the usual approaches. ;I conclude that a semantic approach to the structure of theories offers a natural, precise framework for the characterization of contemporary evolutionary theory. As such, it may provide a means with which progress on outstanding theoretical and philosophical problems can be achieved