This set collects together a vital selection of works on Existentialism, including the key Introduction to the New Existentialism by Colin Wilson. Some of the titles were early works written as this new philosophy spread into the English language, while others are more recent examinations.

Reissuing works originally published between 1949 and ‘79, this set presents a rich selection of renowned scholarship across the subject, touching also on ethics, religion, and psychology and other behavioural science. Classic previously out-of-print works are brought back into print here in this set of important discourse and theory.

This 20 volume Routledge Revivals collection brings together a selection of groundbreaking Philosophy titles, from the rich and diverse Routledge backlist. With titles published between 1933 and 1991, this is a truly wide-ranging selection, encompassing works by distinguished authors such as: Simone Weil, Hilary Putnam, Franz Brentano, Anthony Kenny, Karl Jaspers and Israel Scheffler. Dealing with everything from the notion of freewill, to concepts of time and space, to theories of morality, this set offers a collection of the (...) best of Routledge publishing in the field of Philosophy from across the Twentieth Century. Please note that all titles have been previously available for sale individually through the Routledge Revivals programme. (shrink)

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s (...) but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units.The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals. (shrink)

The notion of structure of evolution is proposed to capture what it means to say that two situations exhibit the same or similar constellations of factors affecting evolution. The key features of holobiont evolution and the hologenome theory are used to define a holobiont structure of evolution. Finally, Cultural Group Selection, a set of hypotheses regarding the evolution of human cognition, is shown to match the holobiont structure closely though not perfectly.

Human cooperation is highly unusual. We live in large groups composed mostly of non-relatives. Evolutionists have proposed a number of explanations for this pattern, including cultural group selection and extensions of more general processes such as reciprocity, kin selection, and multi-level selection acting on genes. Evolutionary processes are consilient; they affect several different empirical domains, such as patterns of behavior and the proximal drivers of that behavior. In this target article, we sketch the evidence from five (...) domains that bear on the explanatory adequacy of cultural group selection and competing hypotheses to explain human cooperation. Does cultural transmission constitute an inheritance system that can evolve in a Darwinian fashion? Are the norms that underpin institutions among the cultural traits so transmitted? Do we observe sufficient variation at the level of groups of considerable size for group selection to be a plausible process? Do human groups compete, and do success and failure in competition depend upon cultural variation? Do we observe adaptations for cooperation in humans that most plausibly arose by cultural group selection? If the answer to one of these questions is “no,” then we must look to other hypotheses. We present evidence, including quantitative evidence, that the answer to all of the questions is “yes” and argue that we must take the cultural group selection hypothesis seriously. If culturally transmitted systems of rules that limit individual deviance organize cooperation in human societies, then it is not clear that any extant alternative to cultural group selection can be a complete explanation. (shrink)

Multi-level selection can be understood via the Price equation or contextual analysis, which offer incompatible statistical decompositions of evolutionary change into components of group and individual selection. Okasha argued that each approach suffers from problem cases. I introduce further problem cases for the Price approach, arguing that it is appropriate for MLS 2 group selection but not MLS 1. I also show that the problem cases Okasha raises for contextual analysis can be resolved. For some (...) such cases, however, it emerges that there is no determinate answer to the question of how much of the total selective effect was due to group selection compared to individual selection. This suggests that when there is interaction between the effect of group character and individual character, one cannot separate selection into distinct ‘levels’ at all. (shrink)

Group selection is one acknowledged mechanism for the evolution of altruism. It is well known that for altruism to spread by natural selection, interactions must be correlated; that is, altruists must tend to associate with one another. But does group selection itself require correlated interactions? Two possible arguments for answering this question affirmatively are explored. The first is a bad argument, for it rests on a product/process confusion. The second is a more subtle argument, whose (...) validity (or otherwise) turns on issues concerning the meaning of multi-level selection and how it should be modelled. A cautious defence of the second argument is offered. Introduction Multi-level selection and the evolution of altruism Price's equation and multi-level selection Contextual analysis and multi-level selection The neighbour approach Recapitulation and conclusion. (shrink)

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s (...) but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as "replicators" which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be "vehicles" of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units. The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to "organs" of group-level "organisms." Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals. (shrink)

Adaptations can occur at different hierarchical levels, but it can be difficult to identify the level of adaptation in specific cases. A major problem is that selection at a lower level can filter up, creating the illusion of selection at a higher level. We use optimality modeling of the volvocine algae to explore the emergence of genuine group adaptations. We find that it is helpful to develop an explicit model for what group fitness would be in (...) the absence of group-level relationships between traits and group fitness. We call this “counterfactual fitness,” because in many actual cases of interest there are group-level relationships. Once counterfactual fitness is modeled, the difference between effects that filter up and genuine group selection is explicit and so, therefore, is the distinction between apparent and genuine group adaptations. We call the latter group-specific adaptations. Recognizing group-specific adaptations is important because only group-specific adaptations would cause the lower-level units to be maladapted if they were to leave the group and enter a global cell-level population. Thus, as group-specific adaptations evolve, they create selective pressure for increased cohesiveness and individuality of groups. This article suggests that group-specific adaptations could be present in the simplest, earliest branching colonial volvocine species, which do not have distinct specialized cells. The article also makes predictions about the kind of empirical evidence needed to support or refute the hypothesis that a particular trait is a group-level adaptation. (shrink)

Various results show the ‘formal equivalence’ of kin and group selectionist methodologies, but this does not preclude there being a real and useful distinction between kin and group selection processes. I distinguish individual- and population-centred approaches to drawing such a distinction, and I proceed to develop the latter. On the account I advance, the differences between kin and group selection are differences of degree in the structural properties of populations. A spatial metaphor provides a useful (...) framework for thinking about these differences: kin and group selection may be conceptualized as large, overlapping regions of K - G space. I then consider some implications of the account, defend it from possible objections, and further argue that the structural features characteristic of both kin and group selection may recur at multiple levels of biological organization. (shrink)

The aim of this paper is to make an unlikely connection between the old question about the meaning of life and some important concepts in philosophy of biology. More precisely, I argue that while biology is unlikely to help us to figure out the meaning of life, the fact that this question has been considered to be such a crucial one could be explained with the help of some consideration of our evolutionary past. I argue that if there is evidence (...) for group selection in the course of human evolution, this may explain not the meaning of life but rather the reason why we are preoccupied with this question. First, I examine what group selection is and what role it played in human evolution. After surveying the evidence for the claim that in the course of human evolution we lived in isolated group societies, I analyse what influence this social structure had on our present psychological dispositions, including our quest for the meaning of life. (shrink)

In the scientific literature on religious evolution, two competing theories appeal to group selection to explain the relationship between religious belief and altruism, or costly, prosocial behavior. Both theories agree that group selection plays an important role in cultural evolution, affecting psychological traits that individuals acquire through social learning. They disagree, however, about whether group selection has also played a role in genetic evolution, affecting traits that are inherited genetically. Recently, Jonathan Haidt has defended (...) the most fully developed account based on genetic group selection, and I argue here that problems with this account reveal good reasons to doubt that genetic group selection has played any important role in human evolution at all. Thus, considering the role of group selection in religious evolution is important not just because of what it reveals about religious psychology and religious evolution, but also because of what it reveals about the role of group selection in human evolution more generally. (shrink)

Group selection, as advocated by Sober and Wilson, is theoretically plausible, although it remains an open question as to what extent it occurs in nature. If group selection has operated in hominids, it is likely to have selected cultural not genetic variation. A focus on niche construction helps delineate the conditions under which cooperation is favoured. Group selection may favour between-group conflict as well as within-group cooperation.

The key problem in the controversy over group selection is that of defining a criterion of group selection that identifies a distinct causal process that is irreducible to the causal process of individual selection. We aim to clarify this problem and to formulate an adequate model of irreducible group selection. We distinguish two types of group selection models, labeling them type I and type II models. Type I models are invoked to (...) explain differences among groups in their respective rates of production of contained individuals. Type II models are invoked to explain differences among groups in their respective rates of production of distinct new groups. Taking Elliott Sober's model as an exemplar, we argue that although type I models have some biological importance--they force biologists to consider the role of group properties in influencing the fitness of organisms--they fail to identify a distinct group-level causal selection process. Type II models if properly framed, however, do identify a group-level causal selection process that is not reducible to individual selection. We propose such a type II model and apply it to some of the major candidates for group selection. (shrink)

The aim of this paper is to make an unlikely connection between the old question about the meaning of life and some important concepts in philosophy of biology. More precisely, I argue that while biology is unlikely to help us to figure out the meaning of life, the fact that this question has been considered to be such a crucial one could be explained with the help of some consideration of our evolutionary past. I argue that if there is evidence (...) for group selection in the course of human evolution, this may explain not the meaning of life but rather the reason why we are preoccupied with this question. First, I examine what group selection is and what role it played in human evolution. After surveying the evidence for the claim that in the course of human evolution we lived in isolated group societies, I analyse what influence this social structure had on our present psychological dispositions, including our quest for the meaning of life. (shrink)

The six commentaries raise five issues about multi-level selection theory that we attempt to address: (1) replicators without vehicles, (2) group selection and movement between groups, (3) absolute versus relative fitness, (4) group-level psychological adaptions, and (5) multi-level selection as a predictive theory.

The cultural group selection hypothesis is supported by considerations of short-term and long-term behavioral patterns of group members, and the short-term and long-term consequences of that behavior. The key to understanding cooperation lies in understanding that the effect of an extended behavioral pattern does not equal – and might even be opposite to – the added effects of its parts.

Using criteria of relative plausibility, it is possible to make a case for significant group selection over the 100,000 years that Anatomically Modern Humans have been both moral and egalitarian. Our nomadic forebears surely lived in egalitarian communities that levelled social differences and moralistically curbed free-riding behaviour, and this egalitarian syndrome would have had profound effects on levels of selection. First, it reduced phenotypic variation at the within-group level. Second, it increased phenotypic variation at the between- (...) class='Hi'>group level. Third, and crucially, moral sanctioning also permitted groups to sharply curtail free-riding tendencies at the level of phenotype. The result was group selection strong enough to support altruistic genes, and a human nature that was set up for social ambivalence: that nature was mainly selfish and strongly nepotistic, but it was at least modestly and socially significantly altruistic. The effects on human social and moral life were pervasive, both in hunting bands and in more recent manifestations of human society. (shrink)

The evidence compiled in the target article demonstrates that the assumptions of cultural group selection theory are often met, and it is therefore a useful framework for generating plausible hypotheses. However, more can be said about how we can test the predictions of CGS hypotheses against competing explanations using historical, archaeological, and anthropological data.

Humans appear to be possible candidates for group selection because they are often said to live in bands, clans, and tribes. These terms, however, are only names for conceptual categories of people. They do not designate enduring bounded gatherings of people that might be “vehicles of selection.” Hence, group selection has probably not been a major force in human evolution.

If selection at the group level is to be considered more than a mere possibility, it is important to find phenomena that are best explained at this level of selection. I argue that human religious phenomena provide evidence for the selection of a “pious gene” at the group level, which results in a human tendency to believe in a transcendental reality that encourages behavioral conformity to collective as opposed to individual interest.

The group selection controversy is about whether natural selection ever operates at the level of groups, rather than at the level of individual organisms. Traditionally, group selection has been invoked to explain the existence of altruistic behaviour in nature. However, most contemporary evolutionary biologists are highly sceptical of the hypothesis of group selection, which they regard as biologically implausible and not needed to explain the evolution of altruism anyway. But in their recent book, (...) Elliot Sober and David Sloan Wilson [1998] argue that the widespread opposition to group selection is founded on conceptual confusion. The theories that have been propounded as alternatives to group selection are actually group selection in disguise, they maintain. I examine their arguments for this claim, and John Maynard Smith's arguments against it. I argue that Sober and Wilson arrive at a correct position by faulty reasoning. In the final section, I examine the issue of how to apply the principle of natural selection at different levels of the biological hierarchy, which underlies the dispute between Sober and Wilson and Maynard Smith. (shrink)

This article is primarily a study of the group selection controversy, with special emphasis on the period from 1962 to the present, and the rise of inclusive fitness theory. Interest is focused on the relations between individual fitness theory and other fitness theories and on the methodological imperatives used in the controversy over the status of these theories. An appendix formalizes the notion of "assertive part" which is used in the informal discussion of the methodological imperatives elicited from (...) the controversy. (shrink)

The capacity to engage with art is a human universal present in all cultures and just about every individual human. This indicates that this capacity is evolved. In this Critical Notice of Denis Dutton's The Art Instinct, I discuss various evolutionary scenarios and their consequences. Dutton and I both reject the "spandrel" approach that originates from the work of Gould and Lewontin. Dutton proposes, following work of Geoffrey Miller, that art is sexually selected--that art-production is a sign of a fit (...) genome in males. I argue that while assortative mating may well have had a role in the evolution of "the art instinct", group selection is a better explanation. I also take issue with Dutton's "cluster concept" approach to defining art, and argue that it is a universal and essential characteristic of art that it is appreciated both for what it expresses and for the way that it expresses. It thus requires a reflexive capacity that is not operative in the appreciation of sport spectacles and pornography. (shrink)

As various kinds of resources become scarce within the context of today's population, consumption, and environmental problems, conflicts of interest will become more evident, competition become more intense, and certain kinds of ‘unwanted’ behavioural strategies might have a tendency to emerge and be used by a growing number of individuals. In such situations, humans may activate group adaptations. If we have group adaptations, like a tendency to classify humans into in-groups and out-groups and to develop moralities favouring one's (...) in-group, it may be problematic to extend our morality outside our own group, especially in environmental situations where resources become scarce. For such reasons, Unto Others touches upon important topics which cannot be ignored. It is crucial to focus on the conditions under which it will be possible to develop a morality for all humans. (shrink)

Are humans genetically predisposed to exhibit prosocial behaviours? Elliott Sober and David Sloan Wilson have made major contributions to our understanding of this question. In my remarks here I will propose a revision in their definition of altruism, suggest a broader term, ‘prosociality', to account for cooperation in humans, and present evidence for a particular set of human prosocial traits that likely evolved with our species and may account for our unique ability to maintain intricate cooperative networks not based on (...) ties of kinship. (shrink)

Kin selection and group selection were once seen as competing explanatory hypotheses but now tend to be seen as equivalent ways of describing the same basic idea. Yet this ‘equivalence thesis’ seems not to have brought proponents of kin selection and group selection any closer together. This may be because the equivalence thesis merely shows the equivalence of two statistical formalisms without saying anything about causality. W.D. Hamilton was the first to derive an equivalence (...) result of this type. Yet Hamilton was aware of its limitations, and saw that, while illuminating, it papered over some biologically important distinctions. Attending to these distinctions leads to the concept of ‘K-G space’, which helps us see where the biological disagreements between proponents of kin selection and group selection really lie. (shrink)

The question of the levels at which natural selection can be said to operate is much discussed by biologists today and is a key factor in the recent controversy about sociobiology. It is shown that this problem is one to which Charles Darwin addressed himself at some length. It is argued that apart from some slight equivocation over man, Darwin opted firmly for hypotheses supposing selection always to work at the level of the individual rather than the (...) class='Hi'>group. However, natural selection's co-discoverer, Alfred Russel Wallace, endorsed group selection hypotheses. (shrink)

Abstract. Scientists have long puzzled over how homosexual orientation has evolved, given the assumed low relative fitness of homosexual individuals compared to heterosexual individuals. A number of theoretical models for the evolution of homosexuality have been postulated including balance polymorphism, "Fertile females", hypervariability of DNA sequences, kin selection, and "parental manipulation". In this paper, I propose a new group-selection model for the evolution of homosexuality which offers two advantages over existing models: (1) its non-assumption of genetic determinism, (...) and (2) its lack of dependency on an inefficient altruism relation and family dynamics theory. (shrink)

The application of phylogenetic methods to cultural variation raises questions about how cultural adaption works and how it is coupled to cultural transmission. Cultural group selection is of particular interest in this context because it depends on the same kinds of mechanisms that lead to tree-like patterns of cultural variation. Here, we review ideas about cultural group selection relevant to cultural phylogenetics. We discuss why group selection among multiple equilibria is not subject to the (...) usual criticisms directed at group selection, why multiple equilibria are a common phenomena, and why selection among multiple equilibria is not likely to be an important force in genetic evolution. We also discuss three forms of group competition and the processes that cause populations to shift from one equilibrium to another and create a mutation-like process at the group level. (shrink)

Evolutionary anthropology has focused on the origins of war, or rather ethnocentricity, because it epitomizes the problem of group selection, and because war may itself have been the main agent of group selection. The neo-Darwinian synthesis in biology has explained how ethnocentricity might evolve by group selection, and the distinction between evoked culture and adopted culture, suggested by the emerging synthesis in evolutionary psychology, has explained how it might be transmitted. Ethnocentric mechanisms could have (...) evolved by genetic selection in ancestral hominids, or through the interaction of genetic and cultural selection in modern humans, or both. The existence of similar behaviors in chimpanzees and the parallel development of early human societies around the globe are arguments for such inherited mechanisms. There may have been some adaptive breakthroughs in purely cultural evolution, but this process does not seem likely to produce long-term Darwinian adaptations because of the prolificity of cultural traits. Warfare may once have been a major agent of group selection, but the rates of extinction among human groups are so slow as to render this improbable since the rise of state-level societies, whose warfare tends to become a cyclical balance-of-power situation. Perhaps the most serious implication of current evolutionary thought is that the individualistic model of culture common in the social sciences and humanities is outmoded, and should be replaced by a new model that recognizes the organismic nature of human societies. (shrink)

argues that correlated interactions are necessary for group selection. His argument turns on a particular procedure for measuring the strength of selection, and employs a restricted conception of correlated interaction. It is here shown that the procedure in question is unreliable, and that while related procedures are reliable in special contexts, they do not require correlated interactions for group selection to occur. It is also shown that none of these procedures, all of which employ partial (...) regression methods, are reliable when correlated interactions of a specific kind arise, and it is argued that such correlated interactions will likely be ubiquitous in natural populations. Introduction Process and Product Fitness, Mean Fitness, and Phenotypic Change Correlated Interactions Causation Implications CiteULike Connotea Del.icio.us What's this? (shrink)

Abstract.Human altruistic behavior has received a great deal of scientific attention over the past forty years. Altruistic‐like behaviors found among insects and animals have illumined certain human behaviors, and the revival of interest in group selection has focused attention on how sacrificial altruism, although not adaptive for individuals, can be adaptive for groups. Curiously, at the same time that sociobiology has placed greater emphasis on the value of sacrificial altruism, Protestant ethics in America has moved away from it. (...) While Roman Catholic ethics has a longstanding tradition emphasizing an ordering of love, placing love of self second only to love for God, Protestant ethics in America has adopted a similar stance only recently, replacing a strong sacrificial ethic with one focusing on mutual regard for self and others. If sociobiology is correct about the significance of sacrificial altruistic behaviors for the survival of communities, this shift away from sacrificial agape by American Christianity may cut the community off from important resources for the development of a global ethic crucial for the survival of that faith community and humankind itself. (shrink)

Human altruistic behavior has received a great deal of scientific attention over the past forty years. Altruistic-like behaviors found among insects and animals have illumined certain human behaviors, and the revival of interest in group selection has focused attention on how sacrificial altruism, although not adaptive for individuals, can be adaptive for groups. Curiously, at the same time that sociobiology has placed greater emphasis on the value of sacrificial altruism, Protestant ethics in America has moved away from it. (...) While Roman Catholic ethics has a longstanding tradition emphasizing an ordering of love, placing love of self second only to love for God, Protestant ethics in America has adopted a similar stance only recently, replacing a strong sacrificial ethic with one focusing on mutual regard for self and others. If sociobiology is correct about the significance of sacrificial altruistic behaviors for the survival of communities, this shift away from sacrificial agape by American Christianity may cut the community off from important resources for the development of a global ethic crucial for the survival of that faith community and humankind itself. (shrink)

We consider the Stag Hunt in terms of Maynard Smith’s famous Haystack model. In the Stag Hunt, contrary to the Prisoner’s Dilemma, there is a cooperative equilibrium besides the equilibrium where every player defects. This implies that in the Haystack model, where a population is partitioned into groups, groups playing the cooperative equilibrium tend to grow faster than those at the non-cooperative equilibrium. We determine under what conditions this leads to the takeover of the population by cooperators. Moreover, we compare (...) our results to the case of an unstructured population and to the case of the Prisoner’s Dilemma. Finally, we point to some implications our findings have for three distinct ideas: Ken Binmore’s group selection argument in favor of the evolution of efficient social contracts, Sewall Wright’s Shifting Balance theory, and the equilibrium selection problem of game theory. (shrink)

This paper explores two philosophical issues related to Darwin’s treatment of the sterile castes of insects in the Origin of Species. The first aim is to review the scholarly articles on the subjects of Darwin’s acceptance or rejection of natural selection acting at levels above that of the individuals. The second aim is to see whether Darwin’s position on group selection informs in any way contemporary debates on group selection and multilevel selection. The paper (...) arrives at the conclusion that, there is significant evidence in the Origin that Darwin did see natural selection acting at the level of the community, but it is hard to say anything more than evolutionary biology is compatible with multilevel selection if we take this point into account. Many present-day individualistic and pluralistic accounts of natural selection that seek legitimacy from Darwin’s views on the subject open up to charges of anachronism. (shrink)

The evolution of the myxoma virus in Australia has been presented for many years as a test case for the hypothesis that group selection can function effectively `in the wild.' This paper critically examines the myxoma case, and argues that its failure as a test case for this hypothesis has broader implications for debates over the levels of selection.

Group selection may be defined either broadly or narrowly. Narrowly defined group selection may involve either selection for altruism or group selection between alternative evolutionarily stable states. The last variety of group selection is likely to have been particularly important in human evolution.

© Cambridge University Press 2016.Richerson et al. propose cultural group selection as the basis for understanding the evolution of cultural systems. Their proposal does not take into account the nature of cultural idea systems as being constituted at an organizational rather than an individual level. The sealing partners of the Netsilik Inuit exemplify the problem with their account.

We develop an account of laboratory models, which have been central to the group selection controversy. We compare arguments for group selection in nature with Darwin's arguments for natural selection to argue that laboratory models provide important grounds for causal claims about selection. Biologists get information about causes and cause-effect relationships in the laboratory because of the special role their own causal agency plays there. They can also get information about patterns of effects and (...) antecedent conditions in nature. But to argue that some cause is actually responsible in nature, they require an inference from knowledge of causes in the laboratory context and of effects in the natural context. This process, cause detection, forms the core of an analogical argument for group selection. We discuss the differing roles of mathematical and laboratory models in constructing selective explanations at the group level and apply our discussion to the units of selection controversy to distinguish between the related problems of cause determination and evaluation of evidence. Because laboratory models are at the intersection of the two problems, their study is crucial for framing a coherent theory of explanation for evolutionary biology. (shrink)

Studies of group selection have been done with both natural and manipulated populations using plants, insects and birds. Group selection occurred in all studies and often the strength of group selection was equal to that of individual selection. Laboratory selection experiments resulted in the opposite response to individual selection than that predicted. Selection with plants for high leaf area resulted in plants with smaller leaf area and selection for high (...) emigration rate in beetles produced lines with lower rates. The selected traits included interactions among individuals. Theoretical studies have shown that genetically based interactions among individuals can interfere with individual selection. Evolution can be partitioned into selection and the response to selection. A response to selection requires genetic variation. Properties of group genetic structure for the natural populations are discussed. The experimental populations had controlled group structure and demonstrate that populations can respond to group selection under some genetic structures. (shrink)