This paper advances the development of a phylogeny-based psychology in which cognitive ability types are individuated as characters in the evolutionary biological sense. I explain the character concept and its utility in addressing (or dissolving) conceptual problems arising from discoveries of cognitive abilities across a wide range of species. I use the examples of stereopsis in the praying mantis, internal cell-to-cell signaling in plants, and episodic memory in scrub jays to show how anthropocentric cognitive ability types can be reformulated into (...) cognitive characters, thereby promoting the integration of psychology with other sciences of evolved traits. (shrink)

We characterize a type of functional explanation that addresses why a homologous trait originating deep in the evolutionary history of a group remains widespread and largely unchanged across the group’s lineages. We argue that biologists regularly provide this type of explanation when they attribute conserved functions to phenotypic and genetic traits. The concept of conserved function applies broadly to many biological domains, and we illustrate its importance using examples of molecular sequence alignments at the intersection of evolution and cell biology. (...) We use these examples to show how the study of conserved functions can integrate knowledge of a trait’s causal effects on fitness and its history of natural selection without invoking adaptation. We also show how conserved function provides a novel basis for addressing objections against evolutionary functions raised by Robert Cummins. (shrink)

This article presents a distinct sense of ‘mechanism’, which I call the functional sense of mechanism. According to this sense, mechanisms serve functions, and this fact places substantive restrictions on the kinds of system activities ‘for which’ there can be a mechanism. On this view, there are no mechanisms for pathology; pathologies result from disrupting mechanisms for functions. Second, on this sense, natural selection is probably not a mechanism for evolution because it does not serve a function. After distinguishing this (...) sense fromsimilar explications of ‘mechanism’, I argue that it is ubiquitous in biology and has valuable epistemic benefits. (shrink)

Recent accounts of emotional action intend to explain such actions without reference to goals. Nevertheless, these accounts fail to specify the difference between goals and other kinds of motivational states. I offer two remedies. First, I develop an account of goals based on Michael Smith’s arguments for the Humean theory of motivation. On this account, a goal is a unified representation that determines behavior selection criteria and satisfaction conditions for an action. This opens the possibility that mental processes could influence (...) behavior without such a unified representation and hence, without goals. Second, I develop a model of emotions and appetites on which behavior selection criteria can be decoupled from satisfaction conditions. If this model is correct, then in many cases, there is no unified representation that determines the behavior selection criteria and satisfaction conditions of emotional actions. In contrast with many traditional accounts of action, the model suggests the following: Whether or not a behavior constitutes an action does not depend on the agent’s grasp of the behavior’s aim. Rather, a behavior constitutes an action if it was organized by the agent, where an agent can organize actions without a coherent grasp of their aim. Some emotional actions are manifestations of this possibility. (shrink)

There have been several recent attempts to think about psychological kinds as homologies. Nevertheless, there are serious epistemic challenges for individuating homologous psychological kinds, or cognitive homologies. Some of these challenges are revealed when we look at competing claims of cognitive homology. This paper considers two competing homology claims that compare human anger with putative aggression systems of nonhuman animals. The competition between these hypotheses has been difficult to resolve in part because of what I call the boundary problem: boundaries (...) between instances of psychological kinds (e.g., anger and fear) cannot be directly observed. Thus, there are distinctive difficulties for individuating psychological kinds across lineages. I draw four conclusions from this case study: First, recent evidence from the neuroscience of fear suggests that one of the proposed homologies involves a straightforward conflation of anger and fear. Second, this conflation arises because of the boundary problem. Third, there is an implicit constraint on the operational criteria that is easy to overlook in the psychological case. In this case, ignoring the constraint is part of the problem. Fourth, this is a clear case in which knowledge of homology cannot be accumulated piecemeal. Identifying homologs of human anger requires identifying homologs of fear. (shrink)

John Searle has argued that functions owe their existence to the value that we put into life and survival. In this paper, I will provide a critique of Searle’s argument concerning the ontology of functions. I rely on a standard analysis of functional predicates as relating not only a biological entity, an activity that constitutes the function of this entity and a type of system but also a goal state. A functional attribution without specification of such a goal state has (...) no truth-value. But if completed with a goal state, functional attributions understood as four-place relations attain a truth-value. The truth conditions of all attributions of function involve a dependence claim of the goal state on the function bearer’s activity. The nature of this dependence may differ; I consider five different possibilities: causality, mechanistic constitution, mereology, supervenience and metaphysical grounding. If these dependency relations are objective, Searle’s central ontological thesis fails. What he ought to have said is that our valuing survival or other goal states may be the reason why biology seeks functional knowledge, but this has nothing to do with ontology. I will show further that Searle also raised an interesting challenge concerning the relationship of functional and causal truths, but it does not threaten the objectivity of functions either. At best, it could show that functional vocabulary is eliminable. However, I will show that functional vocabulary is not so eliminable. (shrink)

This notice provides a critical discussion of some of the issues from Alex Rosenberg’s Darwinian Reductionism, in particular proper functions and the relationship of proximate and ultimate biology, developmental programs and genocentrism, biological laws, the principle of natural selection as a fundamental law, genetic determinism, and the definition of “reductionism.”.

Phylogenetics is the study and reconstruction of evolutionary history and is filled with numerous foundational issues of interest to philosophers. This paper briefly introduces some central concepts in the field, describes some of the main methods for inferring phylogenies, and provides some arguments for the superiority of model-based methods such as Likelihood and Bayesian methods over nonparametric methods such as parsimony. It also raises some underdeveloped issues in the field of interest to philosophers.

Abstract“Trait” is a ubiquitous term in biology, but its precise meaning and theoretical foundations remain opaque. After distinguishing between “trait” and “character,” I argue for the value of adopting Theodosius Dobzhansky’s 1956 definition and framework for understanding “trait,” which holds that traits are just “semantic devices” that artificially impose order on continuous biological phenomena. I elaborate on this definition to distinguish between trait validity (compliance with Dobzhansky’s trait definition) and trait utility (usefulness of a trait). As a consequence of this (...) elaboration of the meaning of “trait,” it becomes clear that considerations of adaptation, function, homogeneity and natural kinds have clouded discussions of the meaning of “trait” per se. Combining this account with work by David Hull and examples from contemporary biology, I demonstrate that even broad or heterogeneous traits (including multiple sub-traits) can qualify as valid and useful. As a test case for this understanding of trait, I show how it can help resolve critiques of schizophrenia’s status as a single trait, highlighting the recent advances made within schizophrenia research. (shrink)

Editors' introduction to the special issue on homology (Biology and Philosophy Vol. 22, Issue 5, 2007).

Evolutionary explanations are not only common in the biological sciences, but also widespread outside biology. But an account of how evolutionary explanations perform their explanatory work is still lacking. This paper develops such an account. I argue that available accounts of explanations in evolutionary science miss important parts of the role of history in evolutionary explanations. I argue that the historical part of evolutionary science should be taken as having genuine explanatory force, and that it provides how‐possibly explanations sensu Dray. (...) I propose an account of evolutionary explanations as comparative‐composite explanations consisting of two distinct kinds of explanations, one processual and one historical, that are connected via the explanandum's evolvability to show how the explanandum is the product of its evolutionary past. The account is both a reconstruction of how evolutionary explanations in biology work and a guideline specifying what kind of explanations evolutionary research programs should develop. (shrink)

This paper argues that a minimal notion of function and a notion of normal-proper function are used in explaining how bodies and brains operate. Neither is Cummins’ notion, as originally defined, and yet his is often taken to be the clearly relevant notion for such an explanatory context. This paper also explains how adverting to normal-proper functions, even if these are selected functions, can play a significant scientific role in the operational explanations of complex systems that physiologists and neurophysiologists provide, (...) despite a lack of relevant causal efficacy on the part of such functions. (shrink)

There are two very different ways of thinking about perception. According to representationalism, perceptual states are representations: they represent the world as being a certain way. They have content, which may or may not be different from the content of beliefs. They represent objects as having properties, sometimes veridically, sometimes not. According to relationalism, perception is a relation between the agent and the perceived object. Perceived objects are literally constituents of our perceptual states and not of the contents thereof. Perceptual (...) states are not representations. My aim is to argue that if we frame this debate as a debate about the individuation of perceptual states, rather than the nature of perception, then we can reconcile these two seemingly conflicting ways of thinking about perception. (shrink)

The specialization of visual function within biological function is reason for introducing “homology thinking” into explanations of the visual system. It is argued that such specialization arises when organisms evolve by differentiation from their predecessors. Thus, it is essentially historical, and visual function should be regarded as a lineage property. The colour vision of birds and mammals do not function the same way as one another, on this account, because each is an adaptation to special needs of the visual functions (...) of predecessors—very different kinds of predecessors in each case. Thus, history underlies function. We also see how homology thinking figures in the hierarchical classification of visual systems, and how it supports the explanation of visual function by functional role analysis. (shrink)

Evolutionary developmental biology (Evo-devo) is a vibrant area of contemporary life science that should be (and is) increasingly incorporated into teaching curricula. Although the inclusion of this content is important for biological pedagogy at multiple levels of instruction, there are also philosophical lessons that can be drawn from the scientific practices found in Evo-devo. One feature of particular significance is the interdisciplinary nature of Evo-devo investigations and their resulting explanations. Instead of a single disciplinary approach being the most explanatory or (...) fundamental, different methodologies from biological disciplines must be synthesized to generate empirically adequate explanations. Thus, Evo-devo points toward a non-reductionist epistemology in biology. I review three areas where these synthetic efforts become manifest as a result of Evo-devo’s practices (form versus function reasoning styles; problem-structured investigations; idealizations related to studying model organisms), and then sketch some possible applications to teaching biology. These philosophical considerations provide resources for life science educators to address (and challenge) key aspects of the National Science Education Standards and Benchmarks for Scientific Literacy. (shrink)

“Functional homology” appears regularly in different areas of biological research and yet it is apparently a contradiction in terms—homology concerns identity of structure regardless of form and function. I argue that despite this conceptual tension there is a legitimate conception of ‘homology of function’, which can be recovered by utilizing a distinction from pre-Darwinian physiology (use versus activity) to identify an appropriate meaning of ‘function’. This account is directly applicable to molecular developmental biology and shares a connection to the theme (...) of hierarchy in homology. I situate ‘homology of function’ within existing definitions and criteria for structural assessments of homology, and introduce a criterion of ‘organization’ for judging function homologues, which focuses on hierarchically interconnected interdependencies (similar to relative position and connection for skeletal elements in structural homology). This analysis of biological concepts has at least three broad philosophical consequences: (1) it provides the grounds for the study of behavior and psychological categories as homologues; (2) it demonstrates that philosophers who take selected effect function as primary effectively ignore large portions of comparative, structural, and experimental research, thereby misconstruing biological reasoning and knowledge; and, (3) it underwrites causal generalizations, which illuminates inferences made from model organisms in experimental biology. (shrink)

It remains at best controversial to claim, non-figuratively, that plants are cognitive agents. At the same time, it is taken as trivially true that many animals are cognitive agents, arguably through an implicit or explicit appeal to natural science. Yet, any given definition of cognition implicates at least some further processes, such as perception, action, memory, and learning, which must be observed either behaviorally, psychologically, neuronally, or otherwise physiologically. Crucially, however, for such observations to be intelligible, they must be counted (...) as evidence for some model. These models in turn point to homologies of physiology and behavior that facilitate the attribution of cognition to some non-human animals. But, if one is dealing with a model of animal cognition, it is tautological that only animals can provide evidence, and absurd to claim that plants can. The more substantive claim that, given a general model of cognition, only animals but not plants can provide evidence, must be evaluated on its merits. As evidence mounts that plants meet established criteria of cognition, from physiology to behavior, they continue to be denied entry into the cognitive club. We trace this exclusionary tendency back to Aristotle, and attempt to counter it by drawing on the philosophy of modelling and a range of findings from plant science. Our argument illustrates how a difference in degree between plant and animals is typically mistaken for a difference in kind. (shrink)

The distinction between causal role and selected effect functions is typically framed in terms of their respective explanatory roles. However, much of the controversy over functions in genomics takes place in an investigative, not an explanatory context. Specifically, the process of component-driven functional investigation begins with the designation of some genetic or epigenetic element as functional —i.e. not junk— because it possesses properties that, arguably, suggest some biologically interesting organismal effect. The investigative process then proceeds, in a bottom-up fashion, to (...) search for those effects. I argue that this process encounters a problem reminiscent of one that Gould and Lewontin associated with the adaptationist program. Just as their stereotypical adaptationst became trapped in the myopic pursuit of one selectionist hypothesis after another, so can the investigation of CR functions in genomics lead to an unending series putative organism-level CR functions for junk DNA. This is an acute problem for genomics, because eukaryotic genomes are littered with transposable elements and their deactivated descendants which often masquerade as interesting CR-functional components and it is experimentally onerous to determine whether they lack such a function. I further argue that selectionist reasoning about TE-host coevolutionary dynamics can greatly streamline the investigative process. Importantly, selectionist hypotheses need not be well confirmed to be illuminating in this context. Informed selectionist reasoning about the strategic roles of TEs in the genome offers a corrective to the idea that most of our DNA is somehow CR functional for the organism. (shrink)

Whether “information” exists in biology, and in what sense, has been a topic of much recent discussion. I explore Shannon, Dretskean, and teleosemantic theories, and analyze whether or not they are able to give a successful naturalistic account of information—specifically accounts of meaning and error—in biological systems. I argue that the Shannon and Dretskean theories are unable to account for either, but that the teleosemantic theory is able to account for meaning. However, I argue that it is unable to account (...) for error. Thus I conclude that while talk of informational meaning is justifiable within a naturalistic framework, talk of informational error is not, and must be used in a metaphorical sense only. (shrink)

Philosophical discussions of biological classification have failed to recognise the central role of homology in the classification of biological parts and processes. One reason for this is a misunderstanding of the relationship between judgments of homology and the core explanatory theories of biology. The textbook characterisation of homology as identity by descent is commonly regarded as a definition. I suggest instead that it is one of several attempts to explain the phenomena of homology. Twenty years ago the ‘new experimentalist’ movement (...) in philosophy of science drew attention to the fact that many experimental phenomena have a ‘life of their own’: the conviction that they are real is not dependent on the theories used to characterise and explain them. I suggest that something similar can be true of descriptive phenomena, and that many homologies are phenomena of this kind. As a result the descriptive biology of form and function has a life of its own—a degree of epistemological independence from the theories that explain form and function. I also suggest that the two major ‘homology concepts’ in contemporary biology, usually seen as two competing definitions, are in reality complementary elements of the biological explanation of homology. (shrink)

Dobzhansky argued that biology only makes sense if life on earth has a shared history. But his dictum is often reinterpreted to mean that biology only makes sense in the light of adaptation. Some philosophers of science have argued in this spirit that all work in ‘proximal’ biosciences such as anatomy, physiology and molecular biology must be framed, at least implicitly, by the selection histories of the organisms under study. Others have denied this and have proposed non-evolutionary ways in which (...) biologists can frame these investigations. This paper argues that an evolutionary perspective is indeed necessary, but that it must be a forward-looking perspective informed by a general understanding of the evolutionary process, not a backward-looking perspective informed by the specific evolutionary history of the species being studied. Interestingly, it turns out that there are aspects of proximal biology that even a creationist cannot study except in the light of a theory of their effect on future evolution. (shrink)

Cancer biology features the ascription of normal functions to parts of cancers. At least some ascriptions of function in cancer biology track local normality of parts within the global abnormality of the aberration to which those parts belong. That is, cancer biologists identify as functions activities that, in some sense, parts of cancers are supposed to perform, despite cancers themselves having no purpose. The present paper provides a theory to accommodate these normal function ascriptions—I call it the Modeling Account of (...) Normal Function (MA). MA comprises two claims. First, normal functions are activities whose performance by the function-bearing part contributes to the self-maintenance of the whole system and, thereby, results in the continued presence of that part. Second, MA holds that models of system-level activities that are (partly) constitutive of self-maintenance are improved by including a representation of the relevant function-bearing part and by making reference to the activity/activities that part performs which contribute(s) to those system-level activities. I contrast MA with two other accounts that seek to explicate the ascription of normal functions in biology, namely, the organizational account and the selected effects account. Both struggle to extend to cancer biology. However, I offer ecumenical readings which allow them to recover some ascriptions of normal function to parts of cancers. So, though I contend that MA excels in this respect, the purpose of this paper is served if it provides materials for bridging the gap between cancer biology, philosophy of cancer, and the literature on function. (shrink)

Despite the voluminous literature on biological functions produced over the last 40 years, few philosophers have studied the concept of function as it is used in neuroscience. Recently, Craver (forthcoming; also see Craver 2001) defended the causal role theory against the selected effects theory as the most appropriate theory of function for neuroscience. The following argues that though neuroscientists do study causal role functions, the scope of that theory is not as universal as claimed. Despite the strong prima facie superiority (...) of the causal role theory, the selected effects theory (when properly developed) can handle many cases from neuroscience with equal facility. It argues this by presenting a new theory of function that generalizes the notion of a ‘selection process’ to include processes such as neural selection, antibody selection, and some forms of learning—that is, to include structures that have been differentially retained as well as those that have been differentially reproduced. This view, called the generalized selected effects theory of function, will be defended from criticism and distinguished from similar views in the literature. (shrink)

I distinguish two forms of pluralism about biological functions, between-discipline pluralism and within-discipline pluralism. Between-discipline pluralism holds that different theories of function are appropriate for different subdisciplines of biology and psychology. I provide reasons for rejecting this view. Instead, I recommend within-discipline pluralism, which emphasizes the plurality of function concepts at play within any given subdiscipline of biology and psychology.

A common misunderstanding of the selected effects theory of function is that natural selection operating over an evolutionary time scale is the only functionbestowing process in the natural world. This construal of the selected effects theory conflicts with the existence and ubiquity of neurobiological functions that are evolutionary novel, such as structures underlying reading ability. This conflict has suggested to some that, while the selected effects theory may be relevant to some areas of evolutionary biology, its relevance to neuroscience is (...) marginal. This line of reasoning, however, neglects the fact that synapses, entire neurons, and potentially groups of neurons can undergo a type of selection analogous to natural selection operating over an evolutionary time scale. In the following, I argue that neural selection should be construed, by the selected effect theorist, as a distinct type of function-bestowing process in addition to natural selection. After explicating a generalized selected effects theory of function and distinguishing it from similar attempts to extend the selected effects theory, I do four things. First, I show how it allows one to identify neural selection as a distinct function-bestowing process, in contrast to other forms of neural structure formation such as neural construction. Second, I defend the view from one major criticism, and in so doing I clarify the content of the view. Third, I examine drug addiction to show the potential relevance of neural selection to neuroscientific and psychological research. Finally, I endorse a modest pluralism of function concepts within biology. (shrink)

Most cognitive scientists nowadays tend to think that at least some of the mind’s capacities are the product of biological evolution, yet important conceptual problems remain for all scientists in order to be able to speak coherently of mental or cognitive systems as having evolved naturally. Two of these important problems concern the articulation of adequate, interesting, and empirically useful concepts of homology and variation as applied to cognitive systems. However, systems in cognitive science are usually understood as functional systems (...) of some sort. Thus, to be able to talk about functional systems being homologous requires having a solid, adequate, and empirically articulated concept of functional homology—and the same is true about functional variation. Here I construct an original concept of functional homology that, in my view, adequately systematizes a number of actual uses of the word “functional homology” in a variety of biological disciplines and in ethology. I also propose a number of criteria for the empirical application of the concept that are analogous to the criteria that are currently used in comparative biology, ethology, and molecular developmental genetics. Then I construct a concept of functional variation on the basis of this concept of homology. (shrink)

There is an argument that has recently been deployed in favor of thinking that the mind is mostly (or even exclusively) composed of cognitive modules; an argument that draws from some ideas and concepts of evolutionary and of developmental biology. In a nutshell, the argument concludes that a mind that is massively composed of cognitive mechanisms that are cognitively modular (henceforth, c-modular) is more evolvable than a mind that is not c-modular (or that is scarcely c-modular), since a cognitive mechanism (...) that is c-modular is likely to be biologically modular (henceforth, b-modular), and b-modular characters are more evolvable (e.g., Sperber 2002, Carruthers 2005). In evolutionary biology, the evolvability of a character in an organism is understood as the “organism’s capacity to facilitate the generation of non-lethal selectable phenotypic variation from random mutation” with respect to that character. Here I will argue that the notion of cognitive modularity needed to make this argument plausible will have to be understood in terms of the biological notion of variational independence; that is, it will have to be understood in such a way that a cognitive feature is c-modular only if few or no other morphological changes (cognitive and not) are significantly correlated with variations of that feature arising in members of the relevant population. I will also argue that all –except for (possibly) one—of the connotations contained in a cluster of notions of cognitive modularity widely accepted in some of the mainstream currents of thought in classical cognitive science, are simply irrelevant to the argument. In order to argue for this, I will have to examine the question as to whether there are any strong theoretical connections between (1) those connotations and (2) notions of modularity accepted in biology, specially in evolutionary and in developmental biology, that are thought to be most relevant to arguments to the effect that biological modularity enhances evolvability. (shrink)

I present and defend the generalized selected effects theory (GSE) of function. According to GSE, the function of a trait consists in the activity that contributed to its bearer’s differential reproduction, or differential retention, within a population. Unlike the traditional selected effects (SE) theory, it does not require that the functional trait helped its bearer reproduce; differential retention is enough. Although the core theory has been presented previously, I go significantly beyond those presentations by providing a new argument for GSE (...) and defending it from a recent objection. I also sketch its implications for teleosemantics and philosophy of medicine. (shrink)

I argue that an explicit distinction between cognitive characters and cognitive phenotypes is needed for empirical progress in the cognitive sciences and their integration with evolution-guided sciences. I elaborate what ontological commitment to characters involves and how such a commitment would clarify ongoing debates about the relations between human and nonhuman cognition and the extent of cognitive abilities across biological species. I use theoretical proposals in episodic memory, language, and sociocultural bases of cognition to illustrate how cognitive characters are being (...) introduced in scientific practice. (shrink)

This paper explores an important type of biological explanation called ‘homology thinking.’ Homology thinking explains the properties of a homologue by citing the history of a homologue. Homology thinking is significant in several ways. First, it offers more detailed explanations of biological phenomena than corresponding analogy explanations. Second, it provides an important explanation of character similarity and difference. Third, homology thinking offers a promising account of multiple realizability in biology.

This paper examines the species problem in microbiology and its implications for the species problem more generally. Given the different meanings of ‘species’ in microbiology, the use of ‘species’ in biology is more multifarious and problematic than commonly recognized. So much so, that recent work in microbial systematics casts doubt on the existence of a prokaryote species category in nature. It also casts doubt on the existence of a general species category for all of life (one that includes both prokaryotes (...) and eukaryotes). Prokaryote biology also undermines recent attempts to save the species category, such as the suggestion that species are metapopulation lineages and the idea that ‘species’ is a family resemblance concept. (shrink)

We argue that ecology in general and biodiversity and ecosystem function research in particular need an understanding of functions which is both ahistorical and evolutionarily grounded. A natural candidate in this context is Bigelow and Pargetter’s evolutionary forward-looking account which, like the causal role account, assigns functions to parts of integrated systems regardless of their past history, but supplements this with an evolutionary dimension that relates functions to their bearers’ ability to thrive and perpetuate themselves. While Bigelow and Pargetter’s account (...) focused on functional organization at the level of organisms, we argue that such an account can be extended to functional organization at the community and ecosystem levels in a way that broadens the scope of the reconciliation between ecosystem ecology and evolutionary biology envisioned by many BEF researchers. By linking an evolutionary forward-looking account of functions to the persistence-based understanding of evolution defended by Bouchard and others, and to the theoretical research on complex adaptive systems, we argue that ecosystems, by forming more or less resilient assemblages, can evolve even while they do not reproduce and form lineages. We thus propose a Persistence Enhancing Propensity account of role functions in ecology to account for this overlap of evolutionary and ecological processes. (shrink)

Token physicalism is often viewed as a modest and unproblematic physicalist commitment, as contrasted with type physicalism. This paper argues that the prevalence of functional individuation in biology creates serious problems for token physicalism, because the latter requires that biological entities can be individuated physically and without reference to biological functioning. After characterizing the main philosophical roles for token physicalism, I describe the distinctive uses of functional individuation in models of biological processes. I then introduce some requirements on token identity (...) claims that arise from a position on individuation and identity known as sortalism. An examination of biological examples shows that these sortalist requirements cannot be plausibly met due to differences between individuation by functional biological criteria and by physical criteria. Even without assuming sortalism, token physicalism faces the more basic problem of excluding functionally irrelevant detail from the individuation of biological tokens. I close by suggesting that the philosophical roles for token identity are better fulfilled by a notion of token composition, which promotes a hierarchical picture of individuality. (shrink)

I develop an account of homology and homoplasy drawing on their use in biological inference and explanation. Biologists call on homology and homoplasy to infer character states, support adaptationist explanations, identify evolutionary novelties and hypothesize phylogenetic relationships. In these contexts, the concepts must be understood phylogenetically and kept separate: as they play divergent roles, overlap between the two ought to be avoided. I use these considerations to criticize an otherwise attractive view defended by Gould, Hall, and Ramsey & Peterson. By (...) this view, homology and homoplasy can only be delineated qua some level of description, and some homoplasies (parallelisms) are counted as homologous. I develop an account which retains the first, but rejects the second, aspect of that view. I then characterize parallelisms and convergences in terms of their causal role. By the Strict Continuity account, homology and homoplasy are defined phylogenetically and without overlaps, meeting my restriction. Convergence and parallelisms are defined as two types of homoplasy: convergent homoplasies are largely constrained by external factors, while parallelisms are due to internal constraints. (shrink)

Historical scientists frequently face incomplete data, and lack direct experimental access to their targets. This has led some philosophers and scientists to be pessimistic about the epistemic potential of the historical sciences. And yet, historical science often produces plausible, sophisticated hypotheses. I explain this capacity to generate knowledge in the face of apparent evidential scarcity by examining recent work on Thylacoleo carnifex, the ‘marsupial lion’. Here, we see two important methodological features. First, historical scientists are methodological omnivores, that is, they (...) construct purpose-built epistemic tools tailored to generate evidence about highly specific targets. This allows them to produce multiple streams of independent evidence and thus maximize their epistemic reach. Second, investigative scaffolding: research proceeds in a piece-meal fashion, information only gaining evidential relevance once certain hypotheses are well supported. I illustrate scaffolding in a discussion of the nature of functional ascription in paleobiology. Frequently, different senses of ‘function’ are not discriminated during paleobiological investigation—something which can mar adaptationist investigations of extant organisms. However, I argue that, due to scaffolding, conflating senses of ‘function’ can be the right thing to do. Coarse-grained functional hypotheses are required before it is clear what evidence could discriminate between more fine-grained ones. I draw on omnivory and scaffolding to argue that pessimists make a bad empirical bet. It is a bad idea to bet against the epistemic fortunes of such opportunistic and resourceful scientists, especially when we have reason to think we will systematically underestimate the amount of evidence ultimately available to them. (shrink)

The comparative method grants epistemic access to the biological past. Comparing lineages provides empirical traction on both hypotheses about particular lineages and models of trait evolution. Understanding this evidential role is important. Although philosophers have recently turned their attention to relations of descent, little work exists exploring the status of evidence from convergences. I argue that, where they exist, convergences play a central role in the confirmation of adaptive hypotheses. I focus on ‘analogous inferences’, show how such inferences ought to (...) be analysed and suggest three methods for strengthening their evidential weight. 1 Introduction2 Analogous Inferences2.1 Adaptive explanations and analogies2.2 Analogous inferences2.3 Scope, grain, and specificity3 Parallel Modelling, Integrated Explanations, and Convergent Modelling3.1 Parallel modelling3.2 Integrated explanations3.1 Convergent modelling4 Conclusion. (shrink)

By linking the concepts of homology and morphological organization to evolvability, this paper attempts to (1) bridge the gap between developmental and phylogenetic approaches to homology and to (2) show that developmental constraints and natural selection are compatible and in fact complementary. I conceive of a homologue as a unit of morphological evolvability, i.e., as a part of an organism that can exhibit heritable phenotypic variation independently of the organism’s other homologues. An account of homology therefore consists in explaining how (...) an organism’s developmental constitution results in different homologues/characters as units that can evolve independently of each other. The explanans of an account of homology is developmental, yet the very explanandum is an evolutionary phenomenon: evolvability in a character-by-character fashion, which manifests itself in phylogenetic patterns as recognized by phylogenetic approaches to homology. While developmental constraints and selection have often been viewed as antagonistic forces, I argue that both are complementary as they concern different parts of the evolutionary process. Developmental constraints, conceived of as the presence of the same set of homologues across phenotypic change, pertain to how heritable variation can be generated in the first place (evolvability), while natural selection operates subsequently on the produced variation. (shrink)

This special issue of Applied Ontology is devoted to the foundation, the comparison and the application of functional theories in all areas, with particular attention to the biological and engineering domains. It includes theoretical and technical contributions related to the description, characterization, and application of functions.

In this paper I discuss a recent theory on functions called Organizational Account. This theory seeks to provide a new definition of function that overcomes the distinction between etiological and dispositional accounts and that could be used in biology as well as in technology. I present a definition of function that I think captures the intuitions of Organizational Accounts and consider several objections.

Naturalistic teleological accounts of mental content rely on an etiological theory of function. Nanay has raised a new objection to an etiological theory, and proposed an alternative theory of function that attributes modal force to claims about function. The aim of this paper is both to defend and to cast a new light on an etiological theory of function. I argue against Nanay’s “trait type individuation objection,” suggesting that an etiological theory also attributes modal force to claims about function. An (...) etiological theory of function can be thought to analyze claims about function with modal force, not relying on any theory of counterfactuals. (shrink)

Cancer biologists ascribe normal functions to parts of cancer. Normal functions are activities that parts of systems are in some minimal sense supposed to perform. Cancer biologists’ finding normality within the abnormality of cancer pose difficulties for two main approaches to normal function. One approach claims that normal functions are activities that parts are selected for. However, some parts of cancers that have normal functions aren’t selected to perform them. The other approach claims that normal functions are part-activities typical for (...) the system and that contribute to survival/reproduction. However, cancers are too heterogeneous to establish what’s typical across a type. (shrink)