The fitness of any evolutionary unit can be understood in terms of its two basic components: fecundity (reproduction) and viability (survival). Trade-offs between these fitness components drive the evolution of life-history traits in extant multicellular organisms. We argue that these trade-offs gain special significance during the transition from unicellular to multicellular life. In particular, the evolution of germ–soma specialization and the emergence of individuality at the cell group (or organism) level are also consequences of trade-offs between the two basic fitness (...) components, or so we argue using a multilevel selection approach. During the origin of multicellularity, we study how the group trade-offs between viability and fecundity are initially determined by the cell level trade-offs, but as the transition proceeds, the fitness trade-offs at the group level depart from those at the cell level. We predict that these trade-offs begin with concave curvature in single-celled organisms but become increasingly convex as group size increases in multicellular organisms. We argue that the increasingly convex curvature of the trade-off function is driven by the cost of reproduction which increases as group size increases. We consider aspects of the biology of the volvocine green algae – which contain both unicellular and multicellular members – to illustrate the principles and conclusions discussed. (shrink)

This chapter combines formal models of how the fitness of a collective can become decoupled from the fitness with more empirical work on the volvocine algae. It uses the Volvox clade as a model system. It describes the evolution of altruism in the volvocine green algae. This chapter suggests that altruism may evolve from genes involved in life-history trade-offs. It shows the several cooperation, conflict, and conflict mediation cycles in the volvocine green algae. This cycle of cooperation, conflict, and conflict (...) mediation drives evolutionary transitions in individuality. (shrink)

Adaptations can occur at different hierarchical levels (e.g., cells and multicellular organisms), but it can be difficult to identify the level(s) 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 (i.e., colony-level) 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 (cells in this case) 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)

Understanding good design requires addressing the question of what units undergo natural selection, thereby becoming adapted. There is, therefore, a natural connection between the formal Darwinism project (which aims to connect population genetics with the evolution of design and fitness maximization) and levels of selection issues. We argue that the formal Darwinism project offers contradictory and confusing lines of thinking concerning level(s) of selection. The project favors multicellular organisms over both the lower (cell) and higher (social group) levels as the (...) level of adaptation. Grafen offers four reasons for giving such special status to multicellular organisms: (1) they lack appreciable within-organism cell selection, (2) they have multiple features that appear contrived for the same purpose, (3) they possess a set of phenotypes, and (4) they leave offspring according to their phenotypes. We discuss why these rationales are not compelling and suggest that a more even-handed approach, in which multicellular organisms are not assumed to have special status, would be desirable for a project that aims to make progress on the foundations of evolutionary theory. (shrink)

We review Evolution and the Levels of Selection by Samir Okasha. This important book provides a cohesive philosophical framework for understanding levels-of-selections problems in biology. Concerning evolutionary transitions, Okasha proposes that three stages characterize the shift from a lower level of selection to a higher one. We discuss the application of Okasha’s three-stage concept to the evolutionary transition from unicellularity to multicellularity in the volvocine green algae. Okasha’s concepts are a provocative step towards a more general understanding of the major (...) evolutionary transitions; however, the application of certain ideas to the volvocine model system is not straightforward. (shrink)

Recent philosophical discussions have failed to clarify the roles of the concept fitness in evolutionary theory. Neither the propensity interpretation of fitness nor the construal of fitness as a primitive theoretical term succeed in explicating the empirical content and explanatory power of the theory of natural selection. By appealing to the structure of simple mathematical models of natural selection, we separate out different contrasts which have tended to confuse discussions of fitness: the distinction between what fitness is defined as versus (...) what fitness is a function of, the contrast between adaptedness as an overall property of organisms and specific adaptive capacities, the distinction between actual and potential reproductive success, the role of chance versus systematic causal relations, fitness as applied to organisms as opposed to fitness applied to genotype classes, heritable adaptive capacities of genotypes as opposed to relations between genotypes and the environment. We show how failure to distinguish and properly interrelate these different aspects of “fitness” adds confusion to a number of already complex issues concerning evolutionary theory. On the basis of our discussion of these different aspects of “fitness”, we propose a terminology which makes the necessary distinctions. A central result of our analysis is that the concept of fitness as the overall adaptedness of organisms does not enter into the causal structure of evolutionary explanation, at least to the extent that this structure is represented in the mathematical models of natural selection. (shrink)

All disciplines must define their basic units and core processes. In evolutionary biology, the core process is natural selection and the basic unit of selection and adaptation is the individual. To operationalize the theory of natural selection we must count individuals, as they are the bearers of fitness. While canonical individuals have often been taken to be multicellular organisms, the hierarchy of life shows that new kinds of individuals have evolved. A variety of criteria have been used to define biological (...) individuality. Some criteria rely on the presence/absence of a particular property while others advocate an approach that reflects the process of natural selection. The plethora of approaches to classifying individuality has resulted in confusion regarding how to study individuality in a given taxon. (shrink)

Evolutionary Transitions in Individuality have been responsible for the major transitions in levels of selection and individuality in natural history, such as the origins of prokaryotic and eukaryotic cells, multicellular organisms, and eusocial insects. The integrated hierarchical organization of life thereby emerged as groups of individuals repeatedly evolved into new and more complex kinds of individuals. The Social Protocell Hypothesis proposes that the integrated hierarchical organization of human culture can also be understood as the outcome of an ETI—one that produced (...) a “cultural organism” from a substrate of socially learned traditions that were contained in growing and dividing social communities. The SPH predicts that a threshold degree of evolutionary individuality would have been achieved by 2.0–2.5 Mya, followed by an increasing degree of evolutionary individuality as the ETI unfolded. We here assess the SPH by applying a battery of criteria—developed to assess evolutionary individuality in biological units—to cultural units across the evolutionary history of Homo. We find an increasing agreement with these criteria, which buttresses the claim that an ETI occurred in the cultural realm. (shrink)

Thinking about thought -- Everything's an inference -- Out of context or the situation -- The rational unconscious -- The formerly dismal science -- Should you think like an economist? -- Spilt milk and free lunch -- Foiling foibles -- Coding, counting, correlation, and causality -- Odds and Ns -- Linked up -- Experiments -- Ignore the hippo -- Experiments natural and experiments proper -- Eekonomics -- Don't ask, can't tell -- Thinking, straight and curved -- Logic -- Dialecticism -- (...) Knowing the world -- Kiss and tell -- Keeping it real -- Whom to believe. (shrink)

Foundations of Algorithms, Fifth Edition offers a well-balanced presentation of algorithm design, complexity analysis of algorithms, and computational complexity. Ideal for any computer science students with a background in college algebra and discrete structures, the text presents mathematical concepts using standard English and simple notation to maximize accessibility and user-friendliness. Concrete examples, appendices reviewing essential mathematical concepts, and a student-focused approach reinforce theoretical explanations and promote learning and retention. C++ and Java pseudocode help students better understand complex algorithms. A chapter (...) on numerical algorithms includes a review of basic number theory, Euclid's Algorithm for finding the greatest common divisor, a review of modular arithmetic, an algorithm for solving modular linear equations, an algorithm for computing modular powers, and the new polynomial-time algorithm for determining whether a number is prime. The revised and updated Fifth Edition features an all-new chapter on genetic algorithms and genetic programming, including approximate solutions to the traveling salesperson problem, an algorithm for an artificial ant that navigates along a trail of food, and an application to financial trading. With fully updated exercises and examples throughout and improved instructor resources including complete solutions, an Instructor's Manual and PowerPoint lecture outlines, Foundations of Algorithms is an essential text for undergraduate and graduate courses in the design and analysis of algorithms. Key features include: • The only text of its kind with a chapter on genetic algorithms • Use of C++ and Java pseudocode to help students better understand complex algorithms • No calculus background required • Numerous clear and student-friendly examples throughout the text • Fully updated exercises and examples throughout • Improved instructor resources, including complete solutions, an Instructor's Manual, and PowerPoint lecture outlines. (shrink)

This book examines two questions: Do people make use of abstract rules such as logical and statistical rules when making inferences in everyday life? Can such abstract rules be changed by training? Contrary to the spirit of reductionist theories from behaviorism to connectionism, there is ample evidence that people do make use of abstract rules of inference -- including rules of logic, statistics, causal deduction, and cost-benefit analysis. Such rules, moreover, are easily alterable by instruction as it occurs in classrooms (...) and in brief laboratory training sessions. The fact that purely formal training can alter them and that those taught in one content domain can "escape" to a quite different domain for which they are also highly applicable shows that the rules are highly abstract. The major implication for cognitive science is that people are capable of operating with abstract rules even for concrete, mundane tasks; therefore, any realistic model of human inferential capacity must reflect this fact. The major implication for education is that people can be far more broadly influenced by training than is generally supposed. At high levels of formality and abstraction, relatively brief training can alter the nature of problem-solving for an infinite number of content domains. (shrink)

Reviews evidence which suggests that there may be little or no direct introspective access to higher order cognitive processes. Ss are sometimes unaware of the existence of a stimulus that importantly influenced a response, unaware of the existence of the response, and unaware that the stimulus has affected the response. It is proposed that when people attempt to report on their cognitive processes, that is, on the processes mediating the effects of a stimulus on a response, they do not do (...) so on the basis of any true introspection. Instead, their reports are based on a priori, implicit causal theories, or judgments about the extent to which a particular stimulus is a plausible cause of a given response. This suggests that though people may not be able to observe directly their cognitive processes, they will sometimes be able to report accurately about them. Accurate reports will occur when influential stimuli are salient and are plausible causes of the responses they produce, and will not occur when stimuli are not salient or are not plausible causes. (shrink)

The authors find East Asians to be holistic, attending to the entire field and assigning causality to it, making relatively little use of categories and formal logic, and relying on "dialectical" reasoning, whereas Westerners, are more analytic, paying attention primarily to the object and the categories to which it belongs and using rules, including formal logic, to understand its behavior. The 2 types of cognitive processes are embedded in different naive metaphysical systems and tacit epistemologies. The authors speculate that the (...) origin of these differences is traceable to markedly different social systems. The theory and the evidence presented call into question long-held assumptions about basic cognitive processes and even about the appropriateness of the process–content distinction. (shrink)

Staged 2 different videotaped interviews with the same individual—a college instructor who spoke English with a European accent. In one of the interviews the instructor was warm and friendly, in the other, cold and distant. 118 undergraduates were asked to evaluate the instructor. Ss who saw the warm instructor rated his appearance, mannerisms, and accent as appealing, whereas those who saw the cold instructor rated these attributes as irritating. Results indicate that global evaluations of a person can induce altered evaluations (...) of the person's attributes, even when there is sufficient information to allow for independent assessments of them. Furthermore, Ss were unaware of this influence of global evaluations on ratings of attributes. In fact, Ss who saw the cold instructor actually believed that the direction of influence was opposite to the true direction. They reported that their dislike of the instructor had no effect on their rating of his attributes but that their dislike of his attributes had lowered their global evaluations of him. (shrink)

Bioethics has been subject to considerable social criticism in recent years. One criticism that has caused particular discomfort in the bioethics community is that bioethicists, because of the way their work is funded, are involved in profound conflicts of interest that undermine their title to be considered independent moral commentators on developments in biomedicine and biotechnology. This criticism draws its force from the assumption that bioethics is, or ought to be, a type of normative social criticism. Versions of this criticism (...) come from both the political left and right. For instance, such criticisms include allegations that bioethics is inherently socially conservative, that it is inherently “pro-technology”, that it lays spurious claims to moral and social authority and expertise, that its focus on autonomy links it to neoliberal theories of choice, and that it is an ideological mystification of real social relationships and political power. This commentary paper analyses the problem of bioethical conflict of interest, and argues that the types of conflict of interest facing bioethics are inherent to the role of “public intellectual” that bioethicists generally wish to assume. The paper defends this conception of the role of the bioethicist, arguing that bioethicists should be interested and openly so. (shrink)

This classic, first published in 1969, introduces to English-speaking readers a field which is of increasing importance in contemporary philosophy and theology--hermeneutics, the theory of understanding, or interpretation. Richard E. Palmer, utilizing largely untranslated sources, treats principally of the conception of hermeneutics enunciated by Heidegger and developed into a "philosophical hermeneutics" by Hans-Georg Gadamer. He provides a brief overview of the field by surveying some half-dozen alternate definitions of the term and by examining in detail the contributions of Friedrich (...) Schleiermacher and Wilhelm Dilthey. In the Manifesto which concludes the book, Palmer suggests the potential significance of hermeneutics for literary interpretation. (shrink)

A long-standing challenge to evolutionary theory has been whether it can explain the origin of complex organismal features. We examined this issue using digital organisms—computer programs that self-replicate, mutate, compete and evolve. Populations of digital organisms often evolved the ability to perform complex logic functions requiring the coordinated execution of many genomic instructions. Complex functions evolved by building on simpler functions that had evolved earlier, provided that these were also selectively favoured. However, no particular intermediate stage was essential for evolving (...) complex functions. The first genotypes able to perform complex functions differed from their non-performing parents by only one or two mutations, but differed from the ancestor by many mutations that were also crucial to the new functions. In some cases, mutations that were deleterious when they appeared served as stepping-stones in the evolution of complex features. These findings show how complex functions can originate by random mutation and natural selection. (shrink)

H.P. Grice is known principally for his influential contributions to the philosophy of language, but his work also includes treatises on the philosophy of mind, ethics, and metaphysics--much of which is unpublished to date. This collection of original essays by such philosophers as Nancy Cartwright, Donald Davidson, Gilbert Harman, and P.F. Strawson demonstrates the unified and powerful character of Grice's thoughts on being, mind, meaning, and morals. An introductory essay by the editors provides the first overview of Grice's work.

128 female Ss were asked to make 4 judgments about a young woman after reading her "job application portfolio." Five characteristics of the young woman were manipulated orthogonally. Ss were asked to report how each of the 5 manipulated factors had influenced each of their judgments. "Observer Ss," who had access only to very impoverished descriptions of each of the 5 factors, were asked to predict how each of the factors would influence each of the judgments. Results show that S (...) reports about the effects of the factors on the judgments were in general highly inaccurate; observer predictions were extremely similar to S reports; for the single judgment for which Ss showed substantial accuracy, observer predictions were as accurate as S reports. Results indicate that whatever introspective access to cognitive processes may exist, it is not sufficient to produce generally accurate reports about such processes, nor even to produce reports that differ much from those of poorly informed outside observers. (shrink)