This paper describes a pattern of explanation prevalent in the biological sciences that I call a ‘lineage explanation’. The aim of these explanations is to make plausible certain trajectories of change through phenotypic space. They do this by laying out a series of stages, where each stage shows how some mechanism worked, and the differences between each adjacent stage demonstrates how one mechanism, through minor modifications, could be changed into another. These explanations are important, for though it is widely accepted (...) that there is an ‘incremental constraint’ on evolutionary change, in an important class of cases it is difficult to see how to satisfy this constraint. I show that lineage explanations answer important questions about evolutionary change, but do so by demonstrating differences between individuals rather than invoking population processes, such as natural selection.1. Introduction2. Turning a ‘Scale’ into a ‘Plume’3. Lineage Explanations in Biology3.1. The evolution of eyes3.2. The evolution of feathers4. The Two Dimensions of a Lineage Explanation4.1. The production dimension4.2. The continuity dimension4.3. The dual role of the parts5. Constraining the Explanations6. Operational and Generative Lineages7. Explaining Change Without Populations8. Conclusion. (shrink)

The ArgumentTo describe the attitude of the Jewish tradition toward eugenic ideology and policies, it is necessary to examine classical sources from a contemporary perspective. In the heyday of eugenics, Rabbi Max Reichler (1916) enthusiastically endorsed its ideology, supporting his position with numerous traditional texts. Similar views of traditional teachings on “chosen people” and on the importance of lineage have a certain contemporary following as well. The paper argues, however, that these views involve a one-sided reading of the Jewish tradition (...) and, particularly, the suppression of traditional critiques of lineage and of the notion of a “Jewish race.”. (shrink)

Work was conducted among traditional, subsistence whale hunters in Lamalera, Indonesia, in order to test if strict biological kinship or lineage membership is more important for explaining the organization of cooperative hunting parties ranging in size from 8 to 14 men. Crew identifications were collected for all 853 hunts that occurred between May 3 and August 5, 1999. Lineage identity and genetic relatedness were determined for a sample of 189 hunters. Results of matrix regression show that genetic kinship explains little (...) of the hunters’ affiliations independent of lineage identity. Crew members are much more closely related to each other than expected by chance, but this is due to the correlation between lineage membership and genetic kinship. Lineage members are much more likely to affiliate in crews, but kin with r<0.5 are just as likely not to affiliate. The results are discussed vis-à-vis the evolution of cooperation and group identity. (shrink)

This paper aims to contribute to the existing literature on normative cognition by providing a lineage explanation of human social norm psychology. This approach builds upon theories of goal-directed behavioral control in the reinforcement learning and control literature, arguing that this form of control defines an important class of intentional normative mental states that are instrumental in nature. I defend the view that great ape capacities for instrumental reasoning and our capacity (or family of capacities) for shared intentionality coadapted to (...) each other and argue that the evolution of this capacity has allowed the representation of social norms and the emergence of our capacity for normative guidance. (shrink)

The nonreproductive role of religious women in the European Middle Ages presents the ideal forum for the discussion of elite family strategies within a historical context. I apply the evolutionary concept of kin selection to this group of women in order to explain how a social formation in which religious women failed to reproduce benefited medieval noble lineages. After a brief review of the roles of noble women in the later Middle Ages, I identify two benefits that nonreproductive women (...) provided within a patrilineal inheritance system. First, spatial segregation and Christian ideology together served to curtail the production of offspring who could pose a threat to lineage interests. Second, cloistered noble women served as a strong political and economic bloc that could further lineage interests within a religious context. Finally, I discuss the evolutionary basis for the formation of groups of nonreproductive women. Using the foundation provided by animal behavioral studies, I apply the twin concepts of cooperative breeding and parental manipulation to noble lineages of the medieval period. (shrink)

There are in the Iliad nine examples of individuals, either human or divine, who recount their ancestry in some detail. The overlap of situation, assertion and vocabulary among these nine examples seems to be sufficient to constitute a theme of lineage-boasting.

Charbonneau (2014) and Papale (2021) challenge the necessity of reproduction for evolution by natural selection (ENS) by contending that what really matter for ENS are memory and (re)generation at the population level, rather than lineage-forming reproduction at the local level. In this article, we critically evaluate their reproduction-independent accounts of ENS and defend the importance of lineage-forming reproduction in paradigmatic ENS on both empirical and theoretical grounds. We argue that none of the empirical cases they cite can be used as (...) evidence to demonstrate the existence of paradigmatic ENS without lineage-forming reproduction, and adopting their reproduction-independent views would lead to an account of ENS that is both too liberal and too strict. (shrink)

Supporting Hamilton’s inclusive fitness theory, archival analyses of inheritance patterns in wills have revealed that people invest more of their estates in kin of closer genetic relatedness. Recent classroom experiments have shown that this genetic relatedness effect is stronger for relatives of direct lineage (children, grandchildren) than for relatives of collateral lineage (siblings, nieces, nephews). In the present research, multilevel modeling of more than 1,000 British Columbian wills revealed a positive effect of genetic relatedness on proportions of estates allocated to (...) relatives. This effect was qualified by an interaction with lineage, such that it was stronger for direct than for collateral relatives. Exploratory analyses of the moderating role of benefactors’ sex and estate values showed the genetic relatedness effect was stronger among female and wealthier benefactors. The importance of these moderators to understanding kin investment in modern humans is discussed. (shrink)

This article defends lineage pluralism; the view that biological lineages are not a single, unified type of entity. I analyze aspects of evolutionary theory, phylogenetics, and developmental biology to show that these areas appeal to distinct notions of lineage. I formulate three arguments for lineage pluralism. These arguments undercut the main motivations for lineage monism; the view that biological lineages are a single, unified type of entity. Although this view is rarely made explicit, it is often assumed in (...) philosophy and biology. Hence, this article sheds light on this monistic assumption and shows why lineage pluralism should be adopted instead. (shrink)

This article defends a selective eliminativist position with respect to the concept of “biological lineage” as used in certain areas of contemporary evolutionary biology. We argue that its primary epistemic roles in these contexts—explaining social evolution and cumulative selection—clash with empirical evidence, and that enforcing the concept of “lineage” even obstructs fruitful research avenues in several biological research fields, including phylogenetic research. Drawing on this, we suggest that, in many instances, it would be best to get rid of the concept (...) of “lineage” and think in terms that are more closely aligned with the empirical complexity of the biological world. Specifically, this entails that, instead of looking for the lineage that may have given rise to the entities possessing certain biological characteristics, biologists should generally look for any potential process allowing such possession, with the formation of a lineage just one possibility among many. (shrink)

Frequent evolutionary birth and death events have created a large quantity of biologically important, lineage‐specific DNA within mammalian genomes. The birth and death of DNA sequences is so frequent that the total number of these insertions and deletions in the human population remains unknown, although there are differences between these groups, e.g. transposable elements contribute predominantly to sequence insertion. Functional turnover – where the activity of a locus is specific to one lineage, but the underlying DNA remains conserved – can (...) also drive birth and death. However, this does not appear to be a major driver of divergent transcriptional regulation. Both sequence and functional turnover have contributed to the birth and death of thousands of functional promoters in the human and mouse genomes. These findings reveal the pervasive nature of evolutionary birth and death and suggest that lineage‐specific regions may play an important but previously underappreciated role in human biology and disease. (shrink)

Nature is replete with borderline cases that fall somewhere between organisms and communities, such as lichens, biofilms, and the Portuguese Man-of-War. At first glance, the existence of such borderline cases might suggest that the concept of what constitutes an organism is too fuzzy to be useful in evolutionary biology. Yet, the notion of organisms is entrenched within central debates in evolution, including discussions over how fitness should be measured, what the bearers of adaptations and fitness are, and the status of (...) holobionts. Finally, accounts of organisms can set the stage for explanations of how multicellularity evolved. In particular, characterizing multicellular organisms in terms of the level of cooperation between their cells suggests that their evolution required the presence of mechanisms that could suppress conflict between cells. (shrink)

Mapping the paths that stem and progenitor cells take en route to differentiate and elucidating the underlying molecular controls are key goals in developmental and stem cell biology. However, with population level analyses it is difficult − if not impossible − to define the transition states and lineage trajectory branch points within complex developmental lineages. Single‐cell RNA‐sequencing analysis can discriminate heterogeneity in a population of cells and even identify rare or transient intermediates. In this review, we propose that using (...) these data, one can infer the lineage trajectories of individual stem cells and identify putative branch points. Clonal lineage tracing of stem cells allows one to define the outcome of differentiation. Integrating these single cell‐based approaches provides a robust strategy for establishing and testing models of how an individual stem cell changes through time to differentiate and self‐renew. (shrink)

The fundamental dialectic of Science as a Process is the interaction between two narrative levels. At one level, the book is a historical narrative of one aspect of one ongoing problem in systematics. At the second level, Hull presents a theoretical model of the scientific process which draws heavily on invoked similarities between biological and scientific change. I first situate the model as one alternative among several which loosely fit under the umbrella of 'evolutionary epistemologies.' Second, I explore one of (...) the implications of Hull's model, namely, that insofar as scientific theories are [parts of] "conceptual lineages," they are "conceptual individuals.". (shrink)

The posthumously published diaries and letters of Beauvoir and Sartre challenge the traditional account of Beauvoir as Sartre's philosophical follower. They show Sartre drawing on Beauvoir's account of relations with the Other in her metaphysical novel, She Came to Stay, as he began writing Being and Nothingness, and point to an unexplored Beauvoirean lineage of existentialism, including Bergson as well as Hegel, Kierkegaard, Husserl and Heidegger, and the African-American writer, Richard Wright.

Standard accounts of mental powers are forward-looking: They individuate powers through their potential manifestations. In this article, the authors argue that mental powers are backward-looking as well. The backward-looking dimension of a power—what they call its lineage—opens up and constrains possibilities for potential manifestations, and in doing so, individuates mental powers just as readily as standard, forward-looking accounts. The idea of lineages thus incorporates standard accounts of mental powers, even while broadening the theoretical, rhetorical, and practical reach of an (...) empowered account. (shrink)

Ontologies of living things are increasingly grounded on the concepts and practices of current life science. Biological development is a process, undergone by living things, which begins with a single cell and (in an important class of cases) ends with formation of a multicellular organism. The process of development is thus prima facie central for ideas about biological individuality and organismality. However, recent accounts of these concepts do not engage developmental biology. This paper aims to fill the gap, proposing the (...) lineage view of stem cells as an ontological framework for conceptualizing organismal development. This account is grounded on experimental practices of stem cell research, with emphasis on new techniques for generating biological organization in vitro. On the lineage view, a stem cell is the starting point of a cell lineage with a specific organismal source, time-interval of existence, and ‘tree topology’ of branch-points linking the stem to developmental termini. The concept of ‘enkapsis’ accommodates the cell-organism relation within the lineage view; this hierarchical notion is further explicated by considering the methods and results of stem cell experiments. Results of this examination include a (partial) characterization of stem cells’ developmental versatility, and the context-dependence of developmental processes involving stem cells. (shrink)

The relation between method, concept and theory in science is complicated. I seek to shed light on that relation by considering an instance of it in systematics: The additional challenges phylogeneticists face when reconstructing phylogeny not at a single level, but simultaneously at multiple levels of the hierarchy. How does this complicate the task of phylogenetic inference, and how might it inform and shape the conceptual foundations of phylogenetics? This offers a lens through which the interplay of method, theory and (...) concepts may be understood in systematics, which, in turn, provides data for a more general account. (shrink)

The philosophy of Gilles Deleuze is increasingly gaining the prestige that its inventiveness calls for in the Anglo-American theoretical context. His wide-ranging works on the history of philosophy, cinema, painting, literature, and politics are being taken up and put to work across disciplinary divides, and in interesting and surprising ways. However, the backbone of Deleuze's philosophy – the many and varied sources from which he draws the material for his conceptual innovation – has until now remained relatively obscure and unexplored. (...) This book takes as its goal the examination of this rich theoretical background. Presenting essays by a range of Deleuze scholars and theorists of his work, it is composed of in-depth analyses of the key figures in Deleuze's lineage, whose significance – as a result of either their obscurity or the complexity of their place in the Deleuzean text – has not previously been well understood. Included are essays on Deleuze's relationship with figures as varied as Marx, Simondon, Wronski, Hegel, Hume, Maimon, Ruyer, Kant, Heidegger, Husserl, Reimann, Leibniz, Bergson, and Freud. (shrink)

Charbonneau ( 2014 ) and Papale ( 2021 ) challenge the necessity of reproduction for evolution by natural selection (ENS) by contending that what really matter for ENS are memory and (re)generation at the population level, rather than lineage-forming reproduction at the local level. In this article, we critically evaluate their reproduction-independent accounts of ENS and defend the importance of lineage-forming reproduction in paradigmatic ENS on both empirical and theoretical grounds. We argue that none of the empirical cases they cite (...) can be used as evidence to demonstrate the existence of paradigmatic ENS without lineage-forming reproduction, and adopting their reproduction-independent views would lead to an account of ENS that is both too liberal and too strict. (shrink)

New methods of marking cells enable single clones to be followed during embryonic development. They can be used for the construction of fate maps and for the investigation of induction and determination.

Mutation and lateral transfer are two categories of processes generating genetic diversity in prokaryotic genomes. Their relative importance varies between lineages, yet both are complementary rather than independent, separable evolutionary forces. The replication process inevitably merges together their effects on the genome. We develop the concept of “open lineages” to characterize evolutionary lineages that over time accumulate more changes in their genomes by lateral transfer than by mutation. They contrast with “closed lineages,” in which most of (...) the changes are caused by mutation. Open and closed lineages are interspersed along the branches of any tree of prokaryotes. This patchy distribution conflicts with the basic assumptions of traditional phylogenetic approaches. As a result, a tree representation including both open and closed lineages is a misrepresentation. The evolution of all prokaryotic lineages cannot be studied under a single model unless new phylogenetic approaches that are more pluralistic about lineage evolution are designed. (shrink)

This paper proposes a new and testable view about the nature of species and other evolving lineages, according to which they are feedback systems. On this view, it is a mistake to think gene flow, niche sharing, and trait frequency similarities between populations are among variables that interact to cause some further downstream variable that distinguishes evolving lineages from each other, some sort of “species cohesion” for example. Instead, gene flow, niche sharing, similarities between populations, and other causal (...) variables feed into each other—instances of these at earlier times help cause instances of these same variables at later times. And any lineage-identifying cohesion just is the recurrence or cycling of these feedback relations within metapopulations over generations. Such cohesion can then be represented as variable M within multi-dimensional variable spaces, where values of M vary dynamically with the frequency and magnitude of feedback relations. Related conditions for being a species or other evolving lineage are then clarified. To argue for the development and testing of this view, the paper shows how it improves upon others. (shrink)

Banaji’s essays offer a powerful plea for a renewal of Marxism, a passionate argument to emancipate Marxism from the dead weight of vulgar traditions – with their simplifications, forced abstractions, mechanical reductions, generalised a-historical theorising, and familiar teleologies. To reinvigorate Marxism, argues Banaji, it is essential to use theory creatively, and recognise the need for complexity in thinking about categories. We cannot generalise about modes of production simply by referring to the forms of labour exploitation in the abstract: associate serfdom (...) or coerced labour with feudalism, and free wage-labour with capitalism. Without historical research into the specific ways in which each economy works – its history and logic of operation – we cannot in the abstract characterise a mode of production: we only end up producing a formal evolutionary sequence of modes. Agreeing with the general thrust of the critique mounted in the book, this essay suggests that Banaji’s own arguments often reproduce the binaries and linearities he opposes, and remain framed within certain forms of reductionism. (shrink)

Our reply focuses on three key themes raised in the symposium. First, we discuss an enduring issue in Marxist International Relations: ‘the problematic of the international’ and the problems of methodological internalism. We examine how our interlocutors have responded to this problematic and why we consider these responses insufficient. Specifically, we suggest that the source of our disagreement is grounded in two divergent understandings of the problem of internalism itself. We then reassert the value of our chosen response to the (...) problematic – uneven and combined development. Second, we respond to the criticism that our extension ofUCDas a ‘transmodal’ general abstraction is problematic by further explicating the significance and role of general abstractions in Marxist theory – a point yet addressed by our critics. Finally, we return to the fundamental question at the core of the transition debate: what is capitalism and how do we theorise it? (shrink)

This collection of essays provides a unique statement of the latest thinking from internationally acclaimed political theorists and intellectual historians on the ways in which the intellectual history and political thought of modern Britain have been saturated with imperial concerns.

Daoist Identity is an exploration of the various means by which Daoists over the centuries have created an identity for themselves. Using modern sociological studies of identity formation as its foundation, it brings together a representative sample of in-depth analyses by eminent American and Japanese scholars in the field. The discussion begins with critical examinations of the ways identity was found among the early movements of the Way of Great Peace and the Celestial Masters. The role of sacred texts and (...) literary culture in Daoist identity formation is discussed. The volume then focuses on lineage formation and the increasing role of popular religious practices, such as spirit-writing, in modern Daoism since the Song dynasty. Finally it discusses the Daoist adaptation and reinterpretation of Buddhist rites, such as the feeding of souls in hell and the use of ritual gestures, and the changes made in contemporary Daoism in relation to traditional rites and popular practices. Contributors: Asano Haruji, Suzanne Cahill, M. Csikszentmihalyi, Edward L. Davis, Terry F. Kleeman, Livia Kohn, Mabuchi Masaya, Maruyama Hiroshi, Mitamura Keiko, Mori Yuria, Peter Nickerson, Charles D. Orzech, Harold D. Roth, Shiga Ichiko, Tsuchiya Masaaki. (shrink)

China has undergone a rapid process of modernization since 1949. The modernization process has accelerated with the development of the market economy and rural-to-urban migration after the 1980s. Nevertheless, Chinese regions still exhibit substantial differences in terms of individualist/collectivist cultural orientations. The rice theory and the climato-economic theory have attempted to explain this variation by analyzing provincial-level data. Based on a quantitative analysis of more granular, county-level variables spanning from the early 1990s until 2010, we offer an alternative account of (...) this cultural variety based on lineage development in different Chinese regions. Using the ArcGIS geographic information system, we first present the regional distribution of individualism/collectivism indicators at the county level through descriptive statistics and spatial analysis. We also run a regression model to analyze county-level data on individualism/collectivism that includes three periods. Our multi-level analysis shows that lineage development is a critical variable that explains more regional variation of culture in China when compared to other variables. While rice farming, the key variable of the rice theory, is a significant variable, its explanatory power is less than the lineage variable. Finally, our analysis shows that the climato-economic theory fails to explain the regional variation of culture. (shrink)

The development of T cells and B cells from pluripotent hematopoietic precursors occurs through a stepwise narrowing of developmental potential that ends in lineage commitment. During this process, lineage-specific genes are activated asynchronously, and lineage-inappropriate genes, although initially expressed, are asynchronously turned off. These complex gene expression events are the outcome of the changes in expression of multiple transcription factors with partially overlapping roles in early lymphocyte and myeloid cell development. Key transcription factors promoting B-cell development and candidates for this (...) role in T-cell development are discussed in terms of their possible modes of action in fate determination. We discuss how a robust, stable, cell-type–specific gene expression pattern may be established in part by the interplay between endogenous transcription factors and signals transduced by cytokine receptors, and in part by the network of effects of particular transcription factors on each other. BioEssays 21:726–742, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

“But in the history of cross-breeding, the union effected outside marriage was of infinitely greater importance. The tales of the chroniclers and missionaries often paint a dark picture of the relations between conqueror and Indian woman—rape, kidnapping, sale and exchange of women, a system of concubinage and harems etc.” (Angel Rosenblatt, La Población indigena de América)“There is racial conflict in Latin America and racial harmony which can be seen only by those who have eyes. The governments and the people themselves (...) see them only very late.” (Sarmiento, Conflicto y Armonías de las razas en América)The colonial period left no fertile seeds for a culture in the soil of South America. As Ricardo Rojas assures us, “We do not find a single imaginative work in prose in these three hundred years.” “All of our colonial literature is confined within the limits of the historical genre…everything in it is the unfolding of a chronicle. To fix the memory of social facts, memorials were written to military conquests and hagiographies of spiritual ones, poems on the English invasions and the emancipation of America. Even the brief erotic and religious poems are only monuments in verse, and so are Tejeda's works whose autobiographical character cannot be denied.” (La Literatura Argentina). (shrink)

This essay presents an interpretation of the juridical thought of Cicero, Hugo Grotius and Adam Smith. Focussing upon questions of property, capital accumulation and violence, the essay traces a tension within their writings between a social ethic of human fellowship and compassion, and, a theory of the utility of ‘unsocial’ commercial self-interest. This tension forms a key problem for the tradition of liberal international law. For Grotius and Smith one response to this tension is to attempt to reign in capitalist (...) markets by asserting a range of moral duties to individuals and to the nation-state. The importance of stressing such an interpretation is to reject the flattening-out of the liberal political and juridical tradition by contemporary neoliberal thought, and to reclaim a number of ways of thinking about the global economy and international law in which moral action and political intervention are understood as playing a necessary and essential role. (shrink)

Contemporary biology has inherited two key assumptions from the Modern Synthesis about the nature of population lineages: sexual reproduction is the exemplar for how individuals in population lineages inherit traits from their parents, and random mating is the exemplar for reproductive interaction. While these assumptions have been extremely fruitful for a number of fields, such as population genetics and phylogenetics, they are increasingly unviable for studying the full diversity and evolution of life. I introduce the “mixture” account of (...) population lineages that escapes these assumptions by dissolving the Modern Synthesis’s sharp line separating reproduction and development and characterizing reproductive integration in population lineages by the ephemerality of isolated subgroups rather than random mating. The mixture account provides a single criterion for reproductive integration that accommodates both sexual and asexual reproduction, unifying their treatment under Kevin de Queiroz’s generalized lineage concept of species. The account also provides a new basis for empirically assessing the effect of random mating as an idealization on the empirical adequacy of population genetic models. (shrink)

Many natural and technological systems are complex, with organizational structures that exhibit characteristic patterns but defy concise description. One effective approach to analyzing such systems is in terms of repeated topological motifs. Here, we extend the motif concept to characterize the dynamic behavior of complex systems by introducing developmental motifs, which capture patterns of system growth. As a proof of concept, we use developmental motifs to analyze the developmental cell lineage of the nematode Caenorhabditis elegans, revealing a new perspective on (...) its complex structure. We use a family of computational models to explore how biases arising from the dynamics of the developmental gene network, as well as spatial and temporal constraints acting on development, contribute to this complex organization. © 2010 Wiley Periodicals, Inc. Complexity 16: 48‐57, 2011. (shrink)

The hematopoietic system consists of more than ten differentiated cell types, all of which are derived from a single type of hematopoietic stem cell. The accessibility and interest of this system have made it a model for understanding normal and abnormal differentiation of mammalian cells. Newer techniques have generated a mass of data that requires integrative approaches for analysis and interpretation. The traditional view of the differentiation program holds that a small number of regulators are involved in each stage of (...) cell specification. However, this may not be the case. Recent analyses have shown that almost all substantial subsets of genes, including the set of broadly expressed transcription factors, are expressed in patterns that are unique for each lineage. Further, much of this difference between lineages can be captured in two‐dimensional graphs. Understanding the biologic significance, mechanisms and constraints underlying these differences is a challenge for experimentalists and computational biologists alike. BioEssays 26:1276–1287, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Biologists are nearing the creation of the first fully synthetic eukaryotic genome. Does this mean that we still soon be able to create genomes that are parts of an existing genetic lineage? If so, it might be possible to bring back extinct species. But do genomes that are synthetically assembled, no matter how similar they are to native genomes, really belong to the genetic lineage on which they were modelled? This article will argue that they are situated within the same (...) genetic lineage. To see why requires closely examining whether material overlap between parents and offspring is a necessary feature of biological reproduction. The processes used to create synthetic genomes shows that these processes are a form of scaffolded reproduction because they use external machinery and take ownership of the material parts used to create synthetic genomes. Closely examining these processes also reveals, surprisingly, that ‘synthetic reproduction’ can take place between entities that don’t participate in the same biological lineages. 1Introduction2The Argument for Lineage-less Genomes3Synthetic Eukaryotic Chromosomes and Material Overlap4Biological Reproduction, Material, and Information5Synthetic Reproductive Processes and Their Implications. (shrink)

We address three fundamental questions: What does it mean for an entity to be living? What is the role of inter-organismic collaboration in evolution? What is a biological individual? Our central argument is that life arises when lineage-forming entities collaborate in metabolism. By conceiving of metabolism as a collaborative process performed by functional wholes, which are associations of a variety of lineage-forming entities, we avoid the standard tension between reproduction and metabolism in discussions of life – a tension particularly evident (...) in discussions of whether viruses are alive. Our perspective assumes no sharp distinction between life and non-life, and does not equate life exclusively with cellular or organismal status. We reach this conclusion through an analysis of the capabilities of a spectrum of biological entities, in which we include the pivotal case of viruses as well as prions, plasmids, organelles, intracellular and extracellular symbionts, unicellular and multicellular life-forms. The usual criterion for classifying many of the entities of our continuum as non-living is autonomy. This emphasis on autonomy is problematic, however, because even paradigmatic biological individuals, such as large animals, are dependent on symbiotic associations with many other organisms. These composite individuals constitute the metabolic wholes on which selection acts. Finally, our account treats cooperation and competition not as polar opposites but as points on a continuum of collaboration. We suggest that competitive relations are a transitional state, with multi-lineage metabolic wholes eventually outcompeting selfish competitors, and that this process sometimes leads to the emergence of new types or levels of wholes. Our view of life as a continuum of variably structured collaborative systems leaves open the possibility that a variety of forms of organized matter – from chemical systems to ecosystems – might be usefully understood as living entities. (shrink)