To date, no definition of life has been unequivocally accepted by the scientific community. In frustration, some authors advocate alternatives to standard definitions. These include using a list of characteristic features, focusing on life’s effects, or categorizing biospheres rather than life itself; treating life as a fuzzy category, a process or a cluster of contingent properties; or advocating a ‘wait-and-see’ approach until other examples of life are created or discovered. But these skeptical, operational, and pluralistic approaches have intensified the debate, (...) rather than settled it. Given the failure of even these approaches, we advocate a new strategy. In this paper, we reverse the usual line of reasoning and argue that the “life problem” arises from thinking incorrectly about the nature of life. Scientists most often conceptualize life as a class or kind, with earthly life as a single instance of it. Instead, we advocate thinking about Earth’s Life as an individual, in the way that species are now thought to be. In this view, Life is a monophyletic clade that originated with a last universal common ancestor, and includes all its descendants. We can continue to use the category ‘life’ pragmatically to refer to similarities between various phenomena and Life. But the relevant similarities are a matter of interest and preference, not a matter of fact. The search for other life in the Universe, then, is merely a search for entities that resemble parts of Life in whatever sense astrobiologists find most appealing. This does not mean that the search for evolved complexity elsewhere in the universe or its creation in the lab are futile endeavors, but that debates over whether they count as ‘life’ are. Ironically, finally abandoning the concept ‘life’ may make our searches for evolved complexity more fruitful. We explain why. (shrink)

Explores the development of the ideas of evolutionary biology, particularly as affected by the increasing understanding of genetics and of the chemical basis of inheritance.

Widely acclaimed as the most authoritative and accessible one-volume dictionary available in English this second edition offers an even richer, more comprehensive, and more up-to-date survey of ideas and thinkers written by an international team of 436 contributors. Includes the most comprehensive entries on major philosophers, 400 new entries including over 50 on preeminent contemporary philosophers, extensive coverage of rapidly developing fields such as the philosophy of mind and applied ethics, more entries on non-Western philosophy than any comparable volume, and (...) increased coverage of Continental philosophy. (shrink)

The central insight of Darwin's Origin of Species is that evolution is an ecological phenomenon, arising from the activities of organisms in the 'struggle for life'. By contrast, the Modern Synthesis theory of evolution, which rose to prominence in the twentieth century, presents evolution as a fundamentally molecular phenomenon, occurring in populations of sub-organismal entities - genes. After nearly a century of success, the Modern Synthesis theory is now being challenged by empirical advances in the study of organismal development and (...) inheritance. In this important study, D. M. Walsh shows that the principal defect of the Modern Synthesis resides in its rejection of Darwin's organismal perspective, and argues for 'situated Darwinism': an alternative, organism-centred conception of evolution that prioritises organisms as adaptive agents. His book will be of interest to scholars and advanced students of evolutionary biology and the philosophy of biology. (shrink)

What do biologists want? If, unlike their counterparts in physics, biologists are generally wary of a grand, overarching theory, at what kinds of explanation do biologists aim? A history of the diverse and changing nature of biological explanation in a particularly charged field, "Making Sense of Life" draws our attention to the temporal, disciplinary, and cultural components of what biologists mean, and what they understand, when they propose to explain life.

Concentrating on problems that commonly perplex general readers and beginning students, John Maynard Smith discusses fundamental issues in biology, with emphasis on evolution, development, and cognition. He provides a nontechnical account of molecular genetics, which is the foundation of modern biology, and explores such issues as heredity, animal behavior, the definition and origin of life, the brain and how we know things, artificial and natural intelligence, and genetics. The book is unique in presenting modern ideas in terms that can be (...) understood without an in-depth knowledge of biology. (shrink)

The book Fundamentals of Life is a bold attempt at gathering all basic knowledge of Humanity regarding the 'Mother of all questions': the essence and origin of life. The Editors are aided by first-class prominence in realising these high-set goals, including Christian de Duve (NP Medicine/Biology, 1972), George A. Olah (NP Chemistry, 1994), Gustaf 0. Arrhenius (Origins-of-Life Science, San Diego, CA, USA), Günther von Kiedrowski (Biochemistry, Bochum, Germany), Brian Johnstone (moral Theology, Rome), Paul G. Mezey (Theoretical Chemistry, Saskatoon, Canada) or (...) Julius Rebek, Jr (Chemical Biology, La Jolla, CA, USA) and Kenso Soai (Autocatalysis, Tokyo) [only to name a few] and several others, together with will-be prominences of the youngest generation as Robert Szilagyi (Stereochemistry, Stanford, CA, USA), Massimo Nardello (Theology, Modena) or Alec A. Schaerer (Philosophy, Zurich). The spectrum of the scientific approach is unusually broad. The 48 Chapters are divided into four sections: 'Definitions of Life'; 'Origin(s) of Life', - 'Basic ('background') Research' as well as 'Moral, Religious and Philosophical Aspects'. The sections are of equilibrated size and joined together by an excellent introductory chapter of the Editors: 'Dimensions of Life'. A rich source of concentrated speculations is collected in the chapter 'Short Definitions of Life', where the answers of 81 excellent scientists, all creative in this field, offer unusual intellectual fireworks. The book will become a reference work for a very broad readership ranging from college students to highly specialised research scientists and even clergymen or philosophers. (shrink)

In this short contribution we explore the historical roots of recent synthetic approaches in biology and try to assess their real potential, as well as identify future hurdles or the reasons behind some of the main difficulties they currently face. We suggest that part of these difficulties might not be just the result of our present lack of adequate technical skills or understanding, but could spring directly from the nature of the biological phenomenon itself. In particular, if life is conceived (...) as autonomy in open-ended evolution, which would help to explain the highly complex and dynamic organization of the simplest known organisms (i.e., genetically-instructed cellular metabolisms), external synthetic implementations of such systems, or interventions on them, are bound to interfere with some of their characteristic transformation processes, both at the ontogenetic and phylogenetic scales. In any case, this will prove very revealing and productive, technologically and scientifically speaking, since the knowledge gathered from those implementations/interventions will be extremely valuable in establishing our capacities and limitations to fully comprehend, utilize, and expand the living domain as we know it today. (shrink)

The question ‘what is life?’ has long been a source of philosophical debate and in recent years has taken on increasing scientific importance. The most popular approach among both philosophers and scientists for answering this question is to provide a “definition” of life. In this article I explore a variety of different definitional approaches, both traditional and non-traditional, that have been used to “define” life. I argue that all of them are deeply flawed. It is my contention that a scientifically (...) compelling understanding of the nature of life presupposes an empirically adequate scientific theory (vs. definition) of life; as I argue, scientific theories are not the sort of thing that can be encapsulated in definitions. Unfortunately, as I also discuss, scientists are currently in no position to formulate even a tentative version of such a theory. Recent discoveries in biology and biochemistry have revealed that familiar Earth life represents a single example that may not be representative of life. If this is the case, life on Earth today provides an empirically inadequate foundation for theorizing about life considered generally. I sketch a strategy for procuring the needed additional examples of life without the guidance of a definition or theory of life, and close with an application to NASA’s fledgling search for extraterrestrial life. (shrink)

This book presents the concept of “complementary science” which contributes to scientific knowledge through historical and philosophical investigations. It emphasizes the fact that many simple items of knowledge that we take for granted were actually spectacular achievements obtained only after a great deal of innovative thinking, painstaking experiments, bold conjectures, and serious controversies. Each chapter in the book consists of two parts: a narrative part that states the philosophical puzzle and gives a problem-centred narrative on the historical attempts to solve (...) the puzzle; and the analysis part which provides in-depth analyses of certain scientific, historical, and philosophical aspects of the story. (shrink)

There is no broadly accepted definition of ‘life.’ Suggested definitions face problems, often in the form of robust counter-examples. Here we use insights from philosophical investigations into language to argue that defining ‘life’ currently poses a dilemma analogous to that faced by those hoping to define ‘water’ before the existence of molecular theory. In the absence of an analogous theory of the nature of living systems, interminable controversy over the definition of life is inescapable.

Bringing together the latest scientific advances and some of the most enduring subtle philosophical puzzles and problems, this book collects original historical and contemporary sources to explore the wide range of issues surrounding the nature of life. Selections ranging from Aristotle and Descartes to Sagan and Dawkins are organised around four broad themes covering classical discussions of life, the origins and extent of natural life, contemporary artificial life creations and the definition and meaning of 'life' in its most general form. (...) Each section is preceded by an extensive introduction connecting the various ideas discussed in individual chapters and providing helpful background material for understanding them. With its interdisciplinary perspective, this fascinating collection is essential reading for scientists and philosophers interested in astrobiology, synthetic biology and the philosophy of life. (shrink)

In several disciplines within science—evolutionary biology, molecular biology, astrobiology, synthetic biology, artificial life—and outside science—primarily ethics—efforts to define life have recently multiplied. However, no consensus has emerged. In this article, I argue that this is no accident. I propose a dilemma showing that the project of defining life is either impossible or pointless. The notion of life at stake in this project is either the folk concept of life or a scientific concept. In the former case, empirical evidence shows that (...) life cannot be defined. In the latter case, I argue that, although defining life may be possible, it is pointless. I conclude that scientists, philosophers, and ethicists should discard the project of defining life. (shrink)

This new volume in the acclaimed Oxford Readings in Philosophy sereis offers a selection of the most important philosophical work being done in the new and fast-growing interdisciplinary area of artificial life. Artificial life research seeks to synthesize the characteristics of life by artificial means, particularly employing computer technology. The essays here explore such fascinating themes as the nature of life, the relation between life and mind, and the limits of technology.

According to the received tradition, the language used to to refer to natural kinds in scientific discourse remains stable even as theories about these kinds are refined. In this illuminating book, Joseph LaPorte argues that scientists do not discover that sentences about natural kinds, like 'Whales are mammals, not fish', are true rather than false. Instead, scientists find that these sentences were vague in the language of earlier speakers and they refine the meanings of the relevant natural-kind terms to make (...) the sentences true. Hence, scientists change the meaning of these terms, This conclusions prompts LaPorte to examine the consequences of this change in meaning for the issue of incommensurability and for the progress of science. This book will appeal to students and professional in the philosophy of science, the philosophy of biology and the philosophy of language. (shrink)

All of the attempts to date to find a set of necessary and sufficient conditions for life, in order to provide an essential definition of life, have failed. We only have at our disposal series of lists that contain diverse characteristics usually found in living beings. Some authors have drawn from this fact the conclusion that life is not a natural kind. It will be argued here that this conclusion is too hasty and that if life is understood as a (...) natural kind in the non-essentialist sense of a homeostatic property cluster, it is easy to see why the attempts to find a unique and essentialist definition of life have failed. Understanding life in this way would imply that the pretension to find such a type of definition should be abandoned. (shrink)

Bibliographical Note Abstract Explaining things - introductory remarks General attitudes and the standard view Requirements for a definition Life as the natural selection of replicators Life as an autopoietic system Life as a semiotic phenomenon Downward causation Implicitly well-defined general objects Emergence as explanatory strategy: the observer reappears Concluding remarks Acknowledgements Notes References Bibliographical note: Earlier versions of this paper were presented at the Princeton History of Science Workshop on "Growing Explanations", Princeton University, February 15, 1997; and at the meeting (...) in the International Society for the History, Philosophy and Social Studies of Biology (ISHPSSB) in Seattle, USA, July 16-21, 1997. Different parts were published in a modified form as 1) Emmeche (1997): "Autopoietic systems, replicators, and the search for a meaningful biologic definition of life", Ultimate Reality and Meaning 20 (4): 244-264 [the original title was: "Is the definition of life important?"], and 2) Emmeche (1998): "Defining life as a semiotic phenomenon", Cybernetics & Human Knowing 5 (1): 3-17. The present web version below contains the complete argument of both articles. A further thoroughly rewritten version, accessible also for non-specialists, was made in collaboration with Charbel Niño El-Hani, and translated by him into Portuguese as a contribution to a book (this version can be found at www.nbi.dk/~emmeche/coPubl/99.DefVida.CE.EH.html). (shrink)

This Special Issue of Origins of Life and Evolution of Biospheres contains papers based on the contributions presented at the Conference "Defining Life" held in Paris (France) on 4-5 February, 2008. The main objective of this Conference was to confront speakers from several disciplines--chemists, biochemists, biologists, exo/astrobiologists, computer scientists, philosophers and historians of science--on the topic of the definition of life. Different viewpoints of the problem approached from different perspectives have been expounded and, as a result, common grounds as well (...) as remaining diverging arguments have been identified. In addition to individual talks, two large roundtables gave ample room for speakers to discuss their diverging viewpoints. This volume collects almost all the contributions presented during the Conference and provides a rich spectrum of renewed answers to the ever-standing question "What is Life?". Besides the arguments directly regarding this question, more philosophical or historical reflections are also proposed in this issue that were not presented during the Conference. This volume also offers a synthesis written by J. Gayon taking each contribution into account. To conclude this foreword, we would like to thank all the participants and speakers who made this Conference a most stimulating event. Each provided novel ideas to "Defining Life" while highlighting the extreme difficulty to reach a consensus on this topic. We are also very grateful to the French CNRS Interdisciplinary Program Origines des Planètes et de la Vie (Origins of Planets and Life) for its generous support, as well as to the National Museum of Natural History in Paris for hosting the Conference. We also thank Alan W. Schwartz for generously offering this space for publishing the Proceedings of the Conference. (shrink)