Roberta L. Millstein

I examine the use of the term function in Aldo Leopold’s land ethic, invoked as (1) the healthy functioning of the land community, which is dependent on (2) the maintenance of the characteristic functions of populations that are parts of the land community. The latter can be understood as referring to interactions between species that are the products of coevolution (such as parasite-host, predator-prey) and, thus, in terms of the “selected effect” account of function. The performance of these functions under certain conditions maintain what Leopold took to be the healthy functioning of a land community.

In their book, Defending Biodiversity, Newman, Varner, and Linquist (NVL) cast doubt on whether Leopoldian defenses of biodiversity, in their current form, have been successful. I argue that there is a more accurate interpretation of Leopold that is not subject to the criticisms made by NVL, and that Leopold’s body of work as a whole, including but not limited to the essay “The Land Ethic” in A Sand County Almanac, provides quite a bit of useful guidance and perspective. I begin with a brief summary of some of my own recent work on Leopold. This is intended to orient the reader who is more familiar with J. Baird Callicott’s influential interpretations of Leopold. I then discuss NVL’s Chapter 10 first followed by a discussion of their Chapter 9, responding to their critiques. I then conclude. On the revised interpretation that I have given, Leopold’s land ethic is defended by the method of reflective equilibrium, showing us that the land communities that we are interdependent with have intrinsic value, necessitating preserving their (land) health, which in turn necessitates preserving biodiversity.

In a well-cited book chapter, ecologist Jared Diamond characterizes three main types of experiment performed in community ecology: laboratory experiment, field experiment, and natural experiment. Diamond argues that each form of experiment has strengths and weaknesses, with respect to, for example, realism or the ability to follow a causal trajectory. But does Diamond’s typology exhaust the available kinds of cause-finding practices? Some social scientists have characterized something they call “causal process tracing.” Is this a fourth type of experiment or something else? I examine Diamond’s typology and causal process tracing in the context of a case study concerning the dynamics of wolf and deer populations on the Kaibab Plateau in the 1920s, a case that has been used as a canonical example of a trophic cascade by ecologists but which has also been subject to controversy. I argue that ecologists have profitably deployed causal process tracing together with other types of experiment to help settle questions of causality in this case. It remains to be seen how widespread the use of causal process tracing outside of the social sciences is (or could be), but there are some potentially promising applications, particularly with respect to questions about specific causal sequences.

Sex and sensibility: The role of social selection Content Type Journal Article DOI 10.1007/s11016-010-9464-6 Authors Erika L. Milam, Department of History, University of Maryland, 2115 Francis Scott Key Hall, College Park, MD 20742, USA Roberta L. Millstein, Department of Philosophy, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA Angela Potochnik, Department of Philosophy, University of Cincinnati, P.O. Box 210374, Cincinnati, OH 45221, USA Joan E. Roughgarden, Department of Biology, Stanford University, Stanford, CA 94305-5020, USA Journal Metascience Online ISSN 1467-9981 Print ISSN 0815-0796.

Aldo Leopold’s Land Ethic, an extremely influential view in environmental ethics and conservation biology, is committed to the claim that interdependence between humans, other species, and abiotic entities plays a central role in our ethical responsibilities. Thus, a robust understanding of “interdependence” is necessary for evaluating the viability of the Land Ethic and related views, including ecological ones. I characterize and defend a Leopoldian concept of “interdependence,” arguing that it ought to include both negative and positive causal relations. I also show that strength and type of interdependence can vary with time, space, and context.

The controversy over genetically modified [GM] organisms is often framed in terms of possible hazards for human health. Articles in a previous volume of this *Encyclopedia* give a general overview of GM crops [@Mulvaney2014] and specifically examine human health [@Nordgard2014] and labeling [@Bruton2014] issues surrounding GM organisms. This article explores several other aspects of the controversy: environmental concerns, political and legal disputes, and the aim of "feeding the world" and promoting food security. Rather than discussing abstract, hypothetical GM organisms, this article explores the consequences of the GM organisms that have actually been deployed in the particular contexts that they have been deployed, on the belief that there is little point in discussing GM organisms in an idealized or context-independent way.

Evolutionary theory is thoroughly probabilistic, due to such elements as random mutation, random drift, and stochastic models of speciation and extinction. This uncontroversial claim raises a number of contentious issues: Is evolutionary theory probabilistic in any general sense, or only in a variety of particular, distinct senses? Are these processes inherently probabilistic, or does the use of probabilities simply provide a convenient way to camouflage a multitude of unknown causes? Does chance play an explanatory role in evolutionary theory, and if so, how? My research explores the seemingly disparate meanings of biologists' various usages of the concept of chance in order to shed light on the answers to these questions. ;Recently, philosophers of science have looked to quantum mechanics to settle issues concerning the nature of chance. However, evolutionary theory itself has a decidedly probabilistic character, apart from quantum mechanics; evolutionary theory was given a probabilistic formulation prior to and independently of the development of quantum mechanics. Previous accounts of chance in evolutionary theory have focused primarily on one particular aspect of chance. I examine three distinct areas where chance enters into evolutionary theory in order to provide a comprehensive, synthetic account. Random drift has been the subject of much discussion by philosophers of biology, most notably by Beatty, Brandon, Hodge, Rosenberg, Shanahan, and Sober. My dissertation thus focuses on random drift in order to settle a number of unresolved controversies raised by these philosophers. The discussion of random drift provides a template for exploring random mutation and stochastic models of macroevolution. On the basis of these analyses, I argue that evolutionary theory provides reasons to rethink some of our traditional philosophical ideas about chance

Aldo Leopold's land ethic has been extremely influential among people working in conservation biology, environmental ethics, and related fields. Others have abandoned the land ethic for purportedly being outdated or ethically untenable. Yet, both acceptance of the land ethic and rejection of the land ethic are often based on misunderstandings of Leopold's original meaning – misunderstandings that have become so entrenched as to have the status of myths. This essay seeks to identify and then debunk six myths that have grown up around the land ethic. These myths include misunderstandings about how we should understand key terms like “stability” and “biotic community” as well as the scope and main message of the land ethic. Properly understanding Leopold's original meaning, a meaning derived from ideas he developed after a lifetime of scientific theorizing and hands-on practical knowledge, prevents hasty rejection and provides a sounder basis for conservation policy.

Evolution in its contemporary meaning in biology typically refers to the changes in the proportions of biological types in a population over time (see the entry on the concept of evolution to 1872 for earlier meanings). As evolution is too large of a topic to address thoroughly in one entry, the primary goal of this entry is to serve as a broad overview of contemporary issues in evolution with links to other entries where more in-depth discussion can be found. The entry begins with a brief survey of definitions of evolution, followed by a discussion of the different modes of evolution and related philosophical issues, and ends with a summary of other topics in the philosophy of evolution focusing particularly on topics covered in this encyclopedia.

As a number of biologists and philosophers have emphasized, ‘chance’ has multiple meanings in evolutionary biology. Seven have been identified. I will argue that there is a unified concept of chance underlying these seven, which I call the UCC (Unified Chance Concept). I will argue that each is characterized by which causes are consid- ered, ignored, or prohibited. Thus, chance in evolutionary biology can only be under- stood through understanding the causes at work. The UCC aids in comparing the different concepts and allows us to characterize our concepts of chance in probabilistic terms, i.e. provides a way to translate between ‘chance’ and ‘probability’.

Evolutionary theory (ET) is teeming with probabilities. Probabilities exist at all levels: the level of mutation, the level of microevolution, and the level of macroevolution. This uncontroversial claim raises a number of contentious issues. For example, is the evolutionary process (as opposed to the theory) indeterministic, or is it deterministic? Philosophers of biology have taken different sides on this issue. Millstein (1997) has argued that we are not currently able answer this question, and that even scientific realists ought to remain agnostic concerning the determinism or indeterminism of evolutionary processes. If this argument is correct, it suggests that, whatever we take probabilities in ET to be, they must be consistent with either determinism or indeterminism. This raises some interesting philosophical questions: How should we understand the probabilities used in ET? In other words, what is meant by saying that a certain evolutionary change is more or less probable? Which interpretation of probability is the most appropriate for ET? I argue that the probabilities used in ET are objective in a realist sense, if not in an indeterministic sense. Furthermore, there are a number of interpretations of probability that are objective and would be consistent with ET under determinism or indeterminism. However, I argue that evolutionary probabilities are best understood as propensities of population-level kinds.

The four case studies on chance in evolution provide a rich source for further philosophical analysis. Among the issues raised are the following: Are there different conceptions of chance at work, or is there a common underlying conception? How can a given concept of chance be distinguished from other chance concepts and from nonchance concepts? How can the occurrence of a given chance process be distinguished empirically from nonchance processes or other chance processes? What role does chance play in evolutionary theory? I argue that in order to answer these questions, a careful distinction between process and outcome must be made; however, the purpose of this essay is not to answer these questions definitively, but rather to elaborate on them and to provide a starting point for further discussion

The neutral and nearly neutral theories of molecular evolution are sometimes characterized as theories about drift alone, where drift is described solely as an outcome, rather than a process. We argue, however, that both selection and drift, as causal processes, are integral parts of both theories. However, the nearly neutral theory explicitly recognizes alleles and/or molecular substitutions that, while engaging in weakly selected causal processes, exhibit outcomes thought to be characteristic of random drift. A narrow focus on outcomes obscures the significant role of weakly selected causal processes in the nearly neutral theory.

This paper explores whether natural selection, a putative evolutionary mechanism, and a main one at that, can be characterized on either of the two dominant conceptions of mechanism, due to Glennan and the team of Machamer, Darden, and Craver, that constitute the “new mechanistic philosophy.” The results of the analysis are that neither of the dominant conceptions of mechanism adequately captures natural selection. Nevertheless, the new mechanistic philosophy possesses the resources for an understanding of natural selection under the rubric.

Given the role of values in the deployment of GMOs, given the lack of mandatory and long-term testing of GMOs with outside oversight, and given the demonstrated environmental harms, it is not anti-science to want to GMOs labelled as GMOs. People who would like to avoid GMOs, whether out of concerns for potential health harms or concerns over actual environmental harms, are not being allowed to judge the risks and make choices for themselves and their families. For these reasons—so that people can follow their reasonably held values—we ought to label GMOs as GMOs.

This volume addresses fundamental issues in the philosophy of science in the context of two most intriguing fields: biology and economics. Written by authorities and experts in the philosophy of biology and economics, Mechanism and Causality in Biology and Economics provides a structured study of the concepts of mechanism and causality in these disciplines and draws careful juxtapositions between philosophical apparatus and scientific practice. By exploring the issues that are most salient to the contemporary philosophies of biology and economics and by presenting comparative analyses, the book serves as a platform not only for gaining mutual understanding between scientists and philosophers of the life sciences and those of the social sciences, but also for sharing interdisciplinary research that combines both philosophical concepts in both fields. The book begins by defining the concepts of mechanism and causality in biology and economics, respectively. The second and third parts investigate philosophical perspectives of various causal and mechanistic issues in scientific practice in the two fields. These two sections include chapters on causal issues in the theory of evolution; experiments and scientific discovery; representation of causal relations and mechanism by models in economics. The concluding section presents interdisciplinary studies of various topics concerning extrapolation of life sciences and social sciences, including chapters on the philosophical investigation of conjoining biological and economic analyses with, respectively, demography, medicine and sociology.

Population genetics attempts to measure the influence of the causes of evolution, viz., mutation, migration, natural selection, and random genetic drift, by understanding the way those causes change the genetics of populations. But how does it accomplish this goal? After a short introduction, we begin in section (2) with a brief historical outline of the origins of population genetics. In section (3), we sketch the model theoretic structure of population genetics, providing the flavor of the ways in which population genetics theory might be understood as incorporating causes. In sections (4) and (5) we discuss two specific problems concerning the relationship between population genetics and evolutionary causes, viz., the problem of conceptually distinguishing natural selection from random genetic drift, and the problem of interpreting fitness. In section (6), we briefly discuss the methodology and key epistemological problems faced by population geneticists in uncovering the causes of evolution. Section (7) of the essay contains concluding remarks.

In “‘Population’ is Not a Natural Kind of Kinds,” Jacob Stegenga argues against the claim that the concept of “population” is a natural kind and in favor of conceptual pluralism, ostensibly in response to two papers of mine (Millstein 2009, 2010). Pluralism is often an attractive position in the philosophy of science. It certainly is a live possibility for the concept of population in ecology and evolutionary biology, and I welcome the opportunity to discuss the topic further. However, I argue that the case for conceptual pluralism has not yet been made. In what follows, I first clarify the issues at stake before taking up the topic of conceptual pluralism and responding to Stegenga’s criticisms of the causal interactionist population concept.

Many philosophers have become familiar with Leopold’s land ethic through the writings of J. Baird Callicott, who claims that Leopold bases his land ethic on a ‘protosociobiological’ argument that Darwin gives in the Descent of Man. On this view, which has become the canonical interpretation, Leopold’s land ethic is based on extending our moral sentiments to ecosystems. I argue that the evidence weighs in favor of an alternative interpretation of Leopold; his reference to Darwin does not refer to the Descent, but rather to the Origin of Species, where Darwin discusses the interdependencies between organisms in the struggle for existence.

I respond to Brandon's (2005) criticisms of my earlier (2002) essay. I argue that (1) biologists are inconsistent in their use of the terms 'selection' and 'drift' -- vacillating between 'process' and 'outcome' -- but that the process-oriented definitions I defend make better sense of the neutralist/selectionist debate; (2) Brandon's purported demonstration that there is no qualitative difference between drift and selection as processes begs the question against my account; and (3) biologists (e.g., Kimura) have argued for genuinely neutral variants. Whether any such variants actually exist is an empirical question. However, the philosophical question at hand is conceptual, not empirical.

A number of areas of biology raise questions about what is of value in the natural environment and how we ought to behave towards it: conservation biology, environmental science, and ecology, to name a few. Based on my experience teaching students from these and similar majors, I argue that the field of environmental ethics has much to teach these students. They come to me with pent-up questions and a feeling that more is needed to fully engage in their subjects, and I believe some exposure to environmental ethics can help focus their interests and goals. I identify three primary areas in which environmental ethics can con- tribute to their education. The first is an examination of who (or what) should be considered to be part of our moral community (i.e., the community to whom we owe direct duties). Is it humans only? Or does it include all sentient life? Or all life? Or ecosystems considered holistically? Often, readings implicitly assume one or more of these answers; the goal is to make the student more sensitive to these implicit claims and to get them to think about the different reasons that support them. The second area, related to the first, is the application of the different answers concerning the extent of the ethical community to real environmental issues and problems. Students need to be aware of how the different answers concerning the moral community can imply conflicting answers for how we should act in certain cases and to think about ways to move toward conflict resolution. The third area in which environmental ethics can contribute is a more conceptual one, focusing on central concepts such as biodiversity, sustainability, species, and ecosystems. Exploring and evaluating various meanings of these terms will make students more reflective and thoughtful citizens and biologists, sensitive to the implications that different conceptual choices make.

Recently, philosophers of biology have debated the status of the evolutionary process: is it deterministic or indeterministic? I argue that there is insufficient reason to favor one side of the debate over the other, and that a more philosophically defensible position argues neither for the determinacy nor for the indeterminacy of the evolutionary process. In other words, I maintain that the appropriate stand to take towards the question of the determinism of the evolutionary process is agnosticism. I then suggest that an examination of the phenomenon of developmental noise might yield a solution to the problem.

The latter half of the twentieth century has been marked by debates in evolutionary biology over the relative significance of natural selection and random drift: the so-called “neutralist/selectionist” debates. Yet John Beatty has argued that it is difficult, if not impossible, to distinguish the concept of random drift from the concept of natural selection, a claim that has been accepted by many philosophers of biology. If this claim is correct, then the neutralist/selectionist debates seem at best futile, and at worst, meaningless. I reexamine the issues that Beatty raises, and argue that random drift and natural selection, conceived as processes, can be distinguished from one another.

In the recent philosophical literature, two questions have arisen concerning the status of natural selection: (1) Is it a population-level phenomenon, or is it an organism-level phenomenon? (2) Is it a causal process, or is it a purely statistical summary of lower-level processes? In an earlier work (Millstein, Br J Philos Sci, 57(4):627–653, 2006), I argue that natural selection should be understood as a population-level causal process, rather than a purely statistical population-level summation of lower-level processes or as an organism-level causal process. In a 2009 essay entitled “Productivity, relevance, and natural selection,” Stuart Glennan argues in reply that natural selection is produced by causal pro- cesses operating at the level of individual organisms, but he maintains that there is no causal productivity at the population level. However, there are, he claims, many population-level properties that are causally relevant to the dynamics of evolution- ary processes. Glennan’s claims rely on a causal pluralism that holds that there are two types of causes: causal production and causal relevance. Without calling into question Glennan’s causal pluralism or his claims concerning the causal relevance of natural selection, I argue that natural selection does in fact exhibit causal production at the population level. It is true that natural selection does not fit with accounts of mechanisms that involve decomposition of wholes into parts, such as Glennan’s own. However, it does fit with causal production accounts that do not require decomposition, such as Salmon’s Mark Transmission account, given the extent to which populations act as interacting “objects” in the process of natural selection.

Alexander Rosenberg (1994) claims that the omniscient viewpoint of the evolutionary process would have no need for the concept of random drift. However, his argument fails to take into account all of the processes which are considered to be instances of random drift. A consideration of these processes shows that random drift is not eliminable even given a position of omniscience. Furthermore, Rosenberg must take these processes into account in order to support his claims that evolution is deterministic and that evolutionary biology is an instrumental science.

This chapter provides an introduction to the study of the philosophical notions of mechanisms and causality in biology and economics. This chapter sets the stage for this volume, Mechanism and Causality in Biology and Economics, in three ways. First, it gives a broad review of the recent changes and current state of the study of mechanisms and causality in the philosophy of science. Second, consistent with a recent trend in the philosophy of science to focus on scientific practices, it in turn implies the importance of studying the scientific methods employed by researchers. Finally, by way of providing an overview of each chapter in the volume, this chapter demonstrates that biology and economics are two fertile fields for the philosophy of science and shows how biological and economic mechanisms and causality can be synthesized.