What is Life? I & II

The definition of life in modern biology has been ignored in both theory and philosophical analysis. We will use this session as an invitation to reflect upon and discuss questions about the concept of life, its history and philosophy, the ontology of life, life's emergence and autonomy, standard as well as non-standard approaches to living systems in theoretical biology, the generality, specificity and unity (or disunity) of biology, and the role of definitions and base concepts in science.

[Program Chair's Note:] A similar session was held at the ISHPSSB Meetings in 1993 (Brandeis). Organizer C. Gordon Winder summarizes its outcome. This session revisits the issue with new perspectives, from minimal functional genomes and GAIA to "artificial" and non-carbon-based life.

Organized by: Naomi Dar, Claus Emmeche and Kelly Smith

Ina Roy, University of Pennsylvania [tentative]
"What We Talk about When We Talk about Life"

Both the philosophical and historical literature on definitions of life note repeatedly the difficulty of providing an intensional definition of "life." The difficulty is thrown into relief as entities which we once uneasily as life-like, without quite being live, are now the subjects of everyday parlance and the substance of day to day work and discourse in the biological sciences. An alternative approach to defining life should be considered, one based on the function or functions of the concept of "life" (and the related category, "living things") in biological theories. In one sense, this is an indirect way to define life ñ rather than creating criteria which objects must fit to be considered "living" we can delineate it using the shadow that life throws on scientific theories to determine its size, shape and extent. The benefits and problems of such an approach will be discussed, as well as its potential use in future work in the philosophy of biology. E-mail author for copy of paper.

Naomi Dar, Hebrew University of Jerusalem
"The Definition of Life - Can it be Generalized?"

The definition of life, usually ignored in biology, flows from origin of life theories, as well as from the efforts to search for life on other planets. In order to distinguish between living, or life-like structures, and the non-living ones, within these research domains, a definition of life is essential. The difficulty herein lies in the fact that these definitions of life are embedded in a biochemical analysis of life, and are, therefore, confined to the properties of carbon compounds substances. However, since life is defined in these theories according to its general properties, this begs the question of the generality of life itself - is life a general phenomenon which is likely to emerge in any substance or is it restricted to carbon compounds? The answer to this question depends on our understanding of the properties of life, and the explanation of their derivation. The properties of life may be regarded as both general and abstract, and the detailed biochemical explanation of their origin as a local incidental one limited to the form of life at hand. Alternatively, life can be viewed as emerging out of the physical and chemical forces of carbon compounds and as bound by the possibilities they may yield. The properties of life as delineated by these approaches are general and cannot be abstracted. In other words, the properties of life are common to all the chemical forms defined by biological theories, but are bound by its material properties. In this paper, I shall be arguing that theories of life are more intelligible using the second approach, and therefore the concept of life can be generalized but not abstracted. This argument will be analyzed by applying various philosophical theories to properties, their abstractions and generalizations, and to relations of resemblance. [ Full Paper ]

Claus Emmeche, University of Copenhagen
"Semiosis and the Definition of Life: Universal and Situated Knowledge"

This note attempts to address the apparent conflict between analytic philosophy of biology discussing in a very abstract way the eventual existence of universal definitions of life and the realization that scientific knowledge as other forms of knowledge is always situated, local, context-dependent, so the meaning of concepts must always already be determined by a particular context. This conflict will be elucidated by a case to be briefly introduced, that is, the definition of life as a sign activity (semiosis: the production, action an interpretation of signs, such as 'genetic information' in molecular biology), as recently proposed by one of the non-standard varieties of philosophy of biology; biosemiotics, which is a kind of qualitative organicism.

Some additional work-in-progress remarks about (1) biosemiotics as a philosophy of biology in general, and (2) the relation between biofunction and biosemiotics are available online at: Defining Life, Explaining Emergence (go to the section "Life as a semiotic phenomenon").

Marina de Lima-Tavares and Charbel NiÒo El-Hani, Federal University of Bahia [tentative]
"Is the Earth Living? Analyzing the Gaia Hypothesis from the Point of View of Three Different Definitions of Life"

The Gaia hypothesis claims that the biosphere acts as an adaptive control system, maintaining the Earth in homeostasis. James Lovelock, one of the proponents of this hypothesis, surmises that an analogy between the Earth and typical organisms can be proposed on the grounds of the Gaia concept. Thus, he often characterizes the Earth as a living being. Nonetheless, Lovelock does not elucidate what definition of 'life' or 'living being', if any, provides the basis for such a characterization. In this paper, the claim that the Earth is a living being is analyzed in the light of definitions of life found in three different paradigms of theoretical biology, as established by Claus Emmeche: neo-Darwinian theory of evolution (life as the natural selection of replicators), autopoietic theory (life as the self-defining, circular organization of the autopoietic system), and biosemiotics (life as the functional interpretation of signs in self-organized material code-systems). We argue that the concept of the Earth as a living being is not compatible with the definitions of life found in the neo-Darwinian theory of evolution and biosemiotics, while it may be supported, somewhat doubtfully, when life is defined as autopoiesis. We conclude that the testability and empirical content of the Gaia hypothesis could be more properly emphasized if the assertion that the Earth is living is clearly detached from its hard core or even eliminated. The crucial issue lies in the difficulty of holding this metaphysical claim when we analyze it in the light of the above-mentioned definitions of life. There is no problem, to be sure, with the presence of metaphysical claims in a scientific theory. It is rather a question of whether the claim that the Earth is living can be supported by the definitions of life we examined. This work is part of a project aiming at the analysis of the status of Gaia as a putative scientific theory.

David Magnus, University of Pennsylvania [tentative]
"What is Life?"

Recent research to construct the "minimal genome" for a living organism has been presented as genomics' answer to the question, "what is life"? This research makes several reductionist assumptions about the centrality of the genes in the functioning of cellular life. In this talk, I will place this research in the context of reductionist and metabolist approaches to the definition of life in origins of life research and argue that while the reductionist assumptions may be a useful heuristic they can be problematic if reified. [ Full Paper ]

Robert Pennock, Michigan State University
"Getting A-Life: Negotiating the Border between Virtual and Real"

Is "artificial life" just life that is artificial or does it not even begin to qualify as life in the first place? Advocates of the view that a-life is indeed a form of life generally place emphasis on fact that a-life systems incorporate evolutionary algorithms and thus evolve on their own, exhibiting emergent properties. What might Wittgenstein have said about this? I'll compare Conway's "Game of Life" and Adami's "Avida" system to illustrate the issues. I'll argue that systems like Avida do not just simulate evolution, but actually instantiate it. However, that may be not sufficient to conclude that the "artificial organisms" in such systems are alive. [E-mail author for copy of paper ]