The Narrow Evolutionary Psychology Movement represents itself as a major reorientation of the social/behavioral sciences, a group of sciences previously dominated by something called the ‘Standard Social Science Model’. Narrow Evolutionary Psychology alleges that the SSSM treated the mind, and particularly those aspects of the mind that exhibit cultural variation, as devoid of any marks of its evolutionary history. Adherents of Narrow Evolutionary Psychology often suggest that the SSSM owed more to ideology than to evidence. It was the child of (...) the 1960s, representing a politically motivated insistence on the possibility of changing social arrangements such as gender roles: " ‘Not so long ago jealousy was considered a pointless, archaic institution in need of reform. But like other denials of human nature from the 1960s, this bromide has not aged well.’ ) " This view of history does not ring true to those, like the authors, who have worked in traditions of evolutionary theorizing about the mind that have a continuous history through the 1960s and beyond: traditions such as evolutionary epistemology and psychoevolutionary research into emotion (Griffiths. (shrink)
Several authors have argued that causes differ in the degree to which they are ‘specific’ to their effects. Woodward has used this idea to enrich his influential interventionist theory of causal explanation. Here we propose a way to measure causal specificity using tools from information theory. We show that the specificity of a causal variable is not well-defined without a probability distribution over the states of that variable. We demonstrate the tractability and interest of our proposed measure by measuring the (...) specificity of coding DNA and other factors in a simple model of the production of mRNA. (shrink)
In behavioral ecology some authors regard the innateness concept as irretrievably confused whilst others take it to refer to adaptations. In cognitive psychology, however, whether traits are 'innate' is regarded as a significant question and is often the subject of heated debate. Several philosophers have tried to define innateness with the intention of making sense of its use in cognitive psychology. In contrast, I argue that the concept is irretrievably confused. The vernacular innateness concept represents a key aspect of 'folkbiology', (...) namely, the explanatory strategy that psychologists and cognitive anthropologists have labeled 'folk essentialism'. Folk essentialism is inimical to Darwinism, and both Darwin and the founders of the modern synthesis struggled to overcome this way of thinking about living systems. Because the vernacular concept of innateness is part of folkbiology, attempts to define it more adequately are unlikely to succeed, making it preferable to introduce new, neutral terms for the various, related notions that are needed to understand cognitive development. (shrink)
The etiological approach to ‘proper functions’ in biology can be strengthened by relating it to Robert Cummins' general treatment of function ascription. The proper functions of a biological trait are the functions it is assigned in a Cummins-style functional explanation of the fitness of ancestors. These functions figure in selective explanations of the trait. It is also argued that some recent etiological theories include inaccurate accounts of selective explanation in biology. Finally, a generalization of the notion of selective explanation allows (...) an analysis of the proper functions of human artifacts. (shrink)
We outline three very different concepts of the gene—instrumental, nominal, and postgenomic. The instrumental gene has a critical role in the construction and interpretation of experiments in which the relationship between genotype and phenotype is explored via hybridization between organisms or directly between nucleic acid molecules. It also plays an important theoretical role in the foundations of disciplines such as quantitative genetics and population genetics. The nominal gene is a critical practical tool, allowing stable communication between bioscientists in a wide (...) range of fields grounded in well-defined sequences of nucleotides, but this concept does not embody major theoretical insights into genome structure or function. The post-genomic gene embodies the continuing project of understanding how genome structure supports genome function, but with a deflationary picture of the gene as a structural unit. This final concept of the gene poses a significant challenge to conventional assumptions about the relationship between genome structure and function, and between genotype and phenotype. (shrink)
Philosophers and historians of biology have argued that genes are conceptualized differently in different fields of biology and that these differences influence both the conduct of research and the interpretation of research by audiences outside the field in which the research was conducted. In this paper we report the results of a questionnaire study of how genes are conceptualized by biological scientists at the University of Sydney, Australia. The results provide tentative support for some hypotheses about conceptual differences between different (...) fields of biological research. (shrink)
Some ‘naturalist’ accounts of disease employ a biostatistical account of dysfunction, whilst others use a ‘selected effect’ account. Several recent authors have argued that the biostatistical account offers the best hope for a naturalist account of disease. We show that the selected effect account survives the criticisms levelled by these authors relatively unscathed, and has significant advantages over the BST. Moreover, unlike the BST, it has a strong theoretical rationale and can provide substantive reasons to decide difficult cases. This is (...) illustrated by showing how life-history theory clarifies the status of so-called diseases of old age. The selected effect account of function deserves a more prominent place in the philosophy of medicine than it currently occupies. _1_ Introduction _2_ Biostatistical and Selected Effect Accounts of Function _3_ Objections to the Selected Effect Account _3.1_ Boorse _3.2_ Kingma _3.3_ Hausman _3.4_ Murphy and Woolfolk _4_ Problems for the Biostatistical Account _4.1_ Schwartz _5_ Analysis versus Explication _6_ Explicating Dysfunction: Life History Theory and Senescence _7_ Conclusion. (shrink)
I defend the view that many biological categories are defined by homology against a series of arguments designed to show that all biological categories are defined, at least in part, by selected function. I show that categories of homology are `abnormality inclusive'—something often alleged to be unique to selected function categories. I show that classifications by selected function are logically dependent on classifications by homology, but not vice-versa. Finally, I reject the view that biologists must use considerations of selected function (...) to abstract away from variation and pathology to form a canonical description of a class of biological systems. (shrink)
Ever since Darwin people have worried about the sceptical implications of evolution. If our minds are products of evolution like those of other animals, why suppose that the beliefs they produce are true, rather than merely useful? In this chapter we apply this argument to beliefs in three different domains: morality, religion, and science. We identify replies to evolutionary scepticism that work in some domains but not in others. The simplest reply to evolutionary scepticism is that the truth of beliefs (...) in a certain domain is, in fact, connected to evolutionary success, so that evolution can be expected to design systems that produce true beliefs in that domain. We call a connection between truth and evolutionary success a ‘Milvian bridge’, after the tradition which ascribes the triumph of Christianity at the battle of the Milvian bridge to the truth of Christianity. We argue that a Milvian bridge can be constructed for commonsense beliefs, and extended to scientific beliefs, but not to moral and religious beliefs. An alternative reply to evolutionary scepticism, which has been used defend moral beliefs, is to argue that their truth does not depend on their tracking some external state of affairs. We ask if this reply could be used to defend religious beliefs. (shrink)
In earlier work I have claimed that emotion and some emotions are not `natural kinds'. Here I clarify what I mean by `natural kind', suggest a new and more accurate term, and discuss the objection that emotion and emotions are not descriptive categories at all, but fundamentally normative categories.
A number of philosophers and ‘evolutionary psychologists’ have argued that attacks on adaptationism in contemporary biology are misguided. These thinkers identify anti-adaptationism with advocacy of non-adaptive modes of explanation. They overlook the influence of anti-adaptationism in the development of more rigorous forms of adaptive explanation. Many biologists who reject adaptationism do not reject Darwinism. Instead, they have pioneered the contemporary historical turn in the study of adaptation. One real issue which remains unresolved amongst these methodological advances is the nature of (...) ‘phylogenetic inertia’. To what extent is an adaptive explanation needed for the persistence of a trait as well as its origin? (shrink)
It is unreasonable to assume that our pre-scientific emotion vocabulary embodies all and only those distinctions required for a scientific psychology of emotion. The psychoevolutionary approach to emotion yields an alternative classification of certain emotion phenomena. The new categories are based on a set of evolved adaptive responses, or affect-programs, which are found in all cultures. The triggering of these responses involves a modular system of stimulus appraisal, whose evoluations may conflict with those of higher-level cognitive processes. Whilst the structure (...) of the adaptive responses is innate, the contents of the system which triggers them are largely learnt. The circuits subserving the adaptive responses are probably located in the limbic system. This theory of emotion is directly applicable only to a small sub-domain of the traditional realm of emotion. It can be used, however, to explain the grouping of various other phenomena under the heading of emotion, and to explain various characteristic failings of the pre-scientific conception of emotion. (shrink)
This article examines and rejects the claim that 'innateness is canalization'. Waddington's concept of canalization is distinguished from the narrower concept of environmental canalization with which it is often confused. Evidence is presented that the concept of environmental canalization is not an accurate analysis of the existing concept of innateness. The strategy of 'biologicizing the mind' by treating psychological or behavioral traits as if they were environmentally canalized physiological traits is criticized using data from developmental psychobiology. It is concluded that (...) identifying innateness with environmental canalization can only result in adding unhelpful associations from 'folkbiology' to the relatively precise idea of canalization. (shrink)
The historian Raphael Falk has described the gene as a ‘concept in tension’ (Falk 2000) – an idea pulled this way and that by the differing demands of different kinds of biological work. Several authors have suggested that in the light of contemporary molecular biology ‘gene’ is no more than a handy term which acquires a specific meaning only in a specific scientific context in which it occurs. Hence the best way to answer the question ‘what is a gene’, and (...) the only way to provide a truly philosophical answer to that question is to outline the diversity of conceptions of the gene and the reasons for this diversity. In this essay we draw on the extensive literature in the history of biology to explain how the concept has changed over time in response to the changing demands of the biosciences . Finally, we outline some of the conceptions of the gene current today. The seeds of change are implicit in many of those current conceptions and the future of the gene concept looks set to be at as turbulent as the past. (shrink)
In a recent article in this journal, Zachary Ardern criticizes our view that the most promising candidate for a naturalized criterion of disease is the "selected effects" account of biological function and dysfunction. Here we reply to Ardern’s criticisms and, more generally, clarify the relationship between adaptation and dysfunction in the evolution of health and disease.
In this chapter we examine the relationship between biological information, the key biological concept of specificity, and recent philosophical work on causation. We begin by showing how talk of information in the molecular biosciences grew out of efforts to understand the sources of biological specificity. We then introduce the idea of ‘causal specificity’ from recent work on causation in philosophy, and our own, information theoretic measure of causal specificity. Biological specificity, we argue, is simple the causal specificity of certain biological (...) processes. This, we suggest, means that causal relationships in biology are ‘informational’ relationships simply when they are highly specific relationships. Biological information can be identified with the storage, transmission and exercise of biological specificity. It has been argued that causal relationships should not be regarded as informational relationship unless they are ‘arbitrary’. We argue that, whilst arbitrariness is an important feature of many causal relationships in living systems, it should not be used in this way to delimit biological information. Finally, we argue that biological specificity, and hence biological information, is not confined to nucleic acids but distributed among a wide range of entities and processes. (shrink)
The Developmental Systems approach to evolution is defended against the alternative extended replicator approach of Sterelny, Smith and Dickison (1996). A precise definition is provided of the spatial and temporal boundaries of the life-cycle that DST claims is the unit of evolution. Pacé Sterelny et al., the extended replicator theory is not a bulwark against excessive holism. Everything which DST claims is replicated in evolution can be shown to be an extended replicator on Sterelny et al.s definition. Reasons are given (...) for scepticism about the heuristic value claimed for the extended replicator concept. For every competitive, individualistic insight the replicator theorist has a cooperative, systematic blindspot. (shrink)
Experimental philosophy of science gathers empirical data on how key scientific concepts are understood by particular scientific communities. In this paper we briefly describe two recent studies in experimental philosophy of biology, one investigating the concept of the gene, the other the concept of innateness. The use of experimental methods reveals facts about these concepts that would not be accessible using the traditional method of intuitions about possible cases. It also contributes to the study of conceptual change in science, which (...) we understand as the result of a form of conceptual ecology, in which concepts become adapted to specific epistemic niches. (shrink)
Philosophy of ecology has been slow to become established as an area of philosophical interest, but it is now receiving considerable attention. This area holds great promise for the advancement of both ecology and the philosophy of science. Insights from the philosophy of science can advance ecology in a number of ways. For example, philosophy can assist with the development of improved models of ecological hypothesis testing and theory choice. Philosophy can also help ecologists understand the role and limitations of (...) mathematical models in ecology. On the other side, philosophy of science will be advanced by having ecological case studies as part of the stock of examples. Ecological case studies can shed light on old philosophical topics as well as raise novel issues for the philosophy of science. For example, understanding theoretical terms such as “biodiversity” is important for scientific reasons, but such terms also carry political importance. Formulating appropriate definitions for such terms is thus not a purely scientific matter, and this may prompt a reevaluation of philosophical accounts of defining theoretical terms. We consider some of the topics currently receiving attention in the philosophy of ecology and other topics in need of attention. Our aim is to prompt further exchange between ecology and philosophy of science and to help set the agenda for future work in the philosophy of ecology. The topics covered include: the role of mathematical models, environmental problem formulation, biodiversity, and environmental ethics. (shrink)
Darwinists classify biological traits either by their ancestry (homology) or by their adaptive role. Only the latter can provide traditional natural kinds, but only the former is practicable. Process structuralists exploit this embarrassment to argue for non-Darwinian classifications in terms of underlying developmental mechanisms. This new taxonomy will also explain phylogenetic inertia and developmental constraint. I argue that Darwinian homologies are natural kinds despite having historical essences and being spatio-temporally restricted. Furthermore, process structuralist explanations of biological form require an unwarranted (...) assumption about the space of developmental possibility. (shrink)
This chapter analyzes the notion of human nature and the concept of inner nature from the perspective of developmental systems theory. It explores the folkbiology of human nature and looks at three features associated with traits that are expressions of the inner nature that organisms inherit from their parents: fixity, typicality, teleology.
There remains a division between the work of philosophers who draw on the sciences of the mind to understand emotion and those who see the philosophy of emotion as more self-sufficient. This article examines this methodological division before reviewing some of the debates that have figured in the philosophical literature of the last decade: whether emotion is a single kind of thing, whether there are discrete categories of emotion, and whether emotion is a form of perception. These questions have been (...) addressed by both sides of the methodological divide and the integration of these two approaches would have clear benefits. (shrink)
The emerging discipline of evolutionary developmental biology has opened up many new lines of investigation into morphological evolution. Here I explore how two of the core theoretical concepts in ‘evo-devo’ – modularity and homology – apply to evolutionary psychology. I distinguish three sorts of module – developmental, functional and mental modules and argue that mental modules need only be ‘virtual’ functional modules. Evolutionary psychologists have argued that separate mental modules are solutions to separate evolutionary problems. I argue that the structure (...) of developmental modules in an organism helps determine what counts as a separate evolutionary problem for that organism. I suggest that homology as an organizing principle for research in evolutionary psychology, has been severely neglected in favor of analogy (adaptive function). I consider some arguments suggesting that determining homology is less epistemically demanding than determining adaptive function and argue that psychological categories defined by homology are, in fact, more suitable objects of psychological – and particularly neuropsychological – investigation than categories defined by analogy. (shrink)
Current knowledge about the variety and complexity of the processes that allow regulated gene expression in living organisms calls for a new understanding of genes. A ‘postgenomic’ understanding of genes as entities constituted during genome expression is outlined and illustrated with specific examples that formed part of a survey research instrument developed by two of the authors for an ongoing empirical study of conceptual change in contemporary biology.
Recent work by Brian Skyrms offers a very general way to think about how information flows and evolves in biological networks — from the way monkeys in a troop communicate, to the way cells in a body coordinate their actions. A central feature of his account is a way to formally measure the quantity of information contained in the signals in these networks. In this paper, we argue there is a tension between how Skyrms talks of signalling networks and his (...) formal measure of information. Although Skyrms refers to both how information flows through networks and that signals carry information, we show that his formal measure only captures the latter. We then suggest that to capture the notion of flow in signalling networks, we need to treat them as causal networks. This provides the formal tools to define a measure that does capture flow, and we do so by drawing on recent work defining causal specificity. Finally, we suggest that this new measure is crucial if we wish to explain how evolution creates information. For signals to play a role in explaining their own origins and stability, they can’t just carry information about acts: they must be difference-makers for acts. (shrink)
The current state of knowledge in psychology, cognitive neuroscience and behavioral ecology allows a fairly robust characterization of at least some, so-called ?basic emotions? - short-lived emotional responses with homologues in other vertebrates. Philosophers, however are understandably more focused on the complex emotion episodes that figure in folk-psychological narratives about mental life, episodes such as the evolving jealousy and anger of a person in an unraveling sexual relationship. One of the most pressing issues for the philosophy of emotion is the (...) relationship between basic emotions and these complex emotion episodes. In this paper, I add to the list of existing, not necessarily incompatible, proposals concerning the relationship between basic emotions and complex emotions. I analyze the writings of ?transactional? psychologists of emotion, particularly those who see their work as a contribution to behavioral ecology, and offer a view of the basic emotion that focuses as much on their interpersonal functions as on their intrapersonal functions. Locating basic emotions and their evolutionary development in a context of processes of social interaction, I suggest, provides a way to integrate our knowledge of basic emotions into an understanding of the larger emotional episodes that have more obvious implications for philosophical disciplines such as moral psychology. (shrink)
Integrating the study of human diversity into the human evolutionary sciences requires substantial revision of traditional conceptions of a shared human nature. This process may be made more difficult by entrenched, 'folkbiological' modes of thought. Earlier work by the authors suggests that biologically naive subjects hold an implicit theory according to which some traits are expressions of an animal's inner nature while others are imposed by its environment. In this paper, we report further studies that extend and refine our account (...) of this aspect of folkbiology. We examine biologically naive subjects' judgments about whether traits of an animal are 'innate', 'in its DNA' or 'part of its nature'. Subjects do not understand these three descriptions to be equivalent. Both innate and in its DNA have the connotation that the trait is species-typical. This poses an obstacle to the assimilation of the biology of polymorphic and plastic traits by biologically naive audiences. Researchers themselves may not be immune to the continuing pull of folkbiological modes of thought. (shrink)
Developmental systems theory is an attempt to sum up the ideas of a research tradition in developmental psychobiology that goes back at least to Daniel Lehrman’s work in the 1950s. It yields a representation of evolution that is quite capable of accommodating the traditional themes of natural selection and also the new results that are emerging from evolutionary developmental biology. But it adds something else - a framework for thinking about development and evolution without the distorting dichotomization of biological processes (...) into gene and non-gene and the vestiges of the ‘black-boxing’ of developmental processes in the modern synthesis, such as the asymmetric use of the concept of information. Phenomena that are marginalized in current gene-centric conceptions, such as extra-genetic inheritance, niche construction and phenotypic plasticity are placed center stage. (shrink)
Genetic determinism is the idea that many significant human characteristics are rendered inevitable by the presence of certain genes. The psychologist Susan Oyama has famously compared arguing against genetic determinism to battling the undead. Oyama suggests that genetic determinism is inherent in the way we currently represent genes and what genes do. As long as genes are represented as containing information about how the organism will develop, they will continue to be regarded as determining causes no matter how much evidence (...) exists to the contrary. Philip Kitcher has strongly disputed Oyama’s diagnosis, arguing that the conventional ‘interactionist’ perspective on development is the correct framework for understanding the role of the genes in development. While acknowledging the legitimacy of many of Kitcher’s observations, I believe that Oyama’s view is substantially correct. In this paper I provide several lines of support for support the Oyama diagnosis. (shrink)
We argue that philosophical and historical research can constitute a ‘Biohumanities’ which deepens our understanding of biology itself; engages in constructive 'science criticism'; helps formulate new 'visions of biology'; and facilitates 'critical science communication'. We illustrate these ideas with two recent 'experimental philosophy' studies of the concept of the gene and of the concept of innateness conducted by ourselves and collaborators.
The aim of appraisal theory in the psychology of emotion is to identify the features of the emotion-eliciting situation that lead to the production of one emotion rather than another2. A model of emotional appraisal takes the form of a set of dimensions against which potentially emotion-eliciting situations are assessed. The dimensions of the emotion hyperspace might include, for example, whether the eliciting situation fulfills or frustrates the subject’s goals or whether an actor in the eliciting situation has violated a (...) norm. Richard Lazarus’s well-known model of emotional appraisal has six dimensions, and the regions of the resulting hyperspace that correspond to particular emotions are summarized by Lazarus as the ‘core relational themes’ of those emotions. Anger, for examples, is elicited by the core relational theme ‘a demeaning offence against me and mine’, sadness by ‘having experienced an irrevocable loss’ and guilt by ‘having transgressed a moral imperative’ (Lazarus, 1991). (shrink)
At the beginning of the 1950s most students of animal behavior in Britain saw the instinct concept developed by Konrad Lorenz in the 1930s as the central theoretical construct of the new ethology. In the mid 1950s J.B.S. Haldane made substantial efforts to undermine Lorenz''s status as the founder of the new discipline, challenging his priority on key ethological concepts. Haldane was also critical of Lorenz''s sharp distinction between instinctive and learnt behavior. This was inconsistent with Haldane''s account of the (...) evolution of language, and, according to Haldane, inconsistent with elementary genetics. British attitudes to the instinct concept changed dramatically in the wake of Daniel S. Lehraman''s 1953 critique of Lorenz, and by the 1960s Lorenz drew a clear distinction between his own views and those of the English-speaking ethologists. The inconsistencies between Lorenz''s ideas and the trends in contemporary evolutionary genetics that are reflected in Haldane''s critiques may help to explain why the Lorenzian instinct concept was unable to maintain itself in Britian. (shrink)
The development of evolutionary approaches to psychology from Classical Ethology through Sociobiology to Evolutionary Psychology is outlined and the main tenets of today's Evolutionary Psychology briefly examined: the heuristic value of evolutionary thinking for psychology, the massive modularity thesis and the monomorphic mind thesis.
The type of cognitive theory of emotion traditionally espoused by philosophers of mind makes two central claims. First, that the occurrence of propositional attitudes is essential to the occurrence of emotions. Second, that the identity of a particular emotional state depends upon the propositional attitudes that it involves. In this paper I try to show that there is little hope of developing a theory of emotion which makes these claims true. I examine the underlying defects of the programme, and show (...) that several recent variants fail to repair these defects. Furthermore, even if such a theory could be developed, it would not achieve many of the things that we look to a theory of emotion for. I argue that philosophers should turn their attention to new and more promising approaches. These have been developed by various of the special sciences, while philosophy has remained enthralled by traditional, propositional attitude psychology. (shrink)
It has been suggested that moods are higher order-dispositions. This proposal is considered, and various shortcomings uncovered. The notion of a higher-order disposition is replaced by the more general notion of a higher-order functional state. An account is given in which moods are higher-order functional states, and the overall system of moods is a higher-order functional description of the mind. This proposal is defended in two ways. First, it is shown to capture some central features of our pre-scientific conception of (...) moods. Secondly, it is argued that the account is more likely to be psychologically realistic (in a sense to be defined) than accounts which are behaviourally equivalent, but which do not employ a hierarchy of functional descriptions. It is suggested that the hierarchical structure of the model mirrors a feature of the physical states that realise moods and emotions. (shrink)
I argue that too much attention has been paid to the Baldwin effect. George Gaylord Simpson was probably right when he said that the effect is theoretically possible and may have actually occurred but that this has no major implications for evolutionary theory. The Baldwin effect is not even central to Baldwin's own account of social heredity and biology-culture co-evolution, an account that in important respects resembles the modern ideas of epigenetic inheritance and niche-construction.
Emotion theory is beset by category disputes. Examining the nature and function of scientific classification can make some of these more tractable. The aim of classification is to group particulars into <<natural>> classes - classes whose members share a rich cluster of properties in addition to those used to place them in the class. Classification is inextricably linked to theories of the causal processes that explain why certain particulars resemble one another and so are usefully regarded as <<of the same (...) kind>>. The need to base categories on underlying causal processes explains why mere careful definition (including operational definition) need not produce categories that are productive objects of scientific study. Because different causal processes produce different patterns of similarity there is unlikely to be a single classification that is optimal for addressing all scientific questions. Cultural categories should not be contrasted to natural categories, but should be treated as natural classes generated by underlying social processes. Our capacity to introduce epistemically optimal categories is often restricted because categories play a role in social and political, as well as epistemic, projects. This account of classification has many implications for emotion theory. (shrink)
Throughout his career David Hull has sought to bring the philosophy of science into closer contact with science and especially with biological science (Hull 1969, 1997b). This effort has taken many forms. Sometimes it has meant ‘either explaining basic biology to philosophers or explaining basic philosophy to biologists’ (Hull 1996, p. 77). The ﬁrst of these tasks, simple as it sounds, has been responsible for revolutionary changes. It is well known that traditional philosophy of science, modeled as it was on (...) theoretical physics, proved inadequate when philosophers turned their attention to biological science. Biological examples have driven major revisions of accounts of reduction (Hull 1974; Schaffner 1993, Ch. 9), laws of nature (Beatty et al. 1997), theories (Lloyd 1988) and natural kinds (Wilson 1999, Part III). Nor is explaining basic philosophy to biologists a task to be looked down upon. It is useful, not because philosophy has all the answers, but because scientists must think about how to do science, that is doing philosophy of science and scientists frequently reinvent philosophical views with known ﬂaws. Early in his career Hull found biological systematists in the grip of a crude operationalism about scientiﬁc concepts and said so in the pages of Systematic Zoology (Hull 1968). For the next thirty years, as biologists debated the nature of species and the correct principles of classiﬁcation, Hull added a philosophical note at the same congresses and in the same journals (Hull 1970, 1976, 1980, 1997a, 1999). (shrink)