We study connections between classical asymptotic density, computability and computable enumerability. In an earlier paper, the second two authors proved that there is a computably enumerable set A of density 1 with no computable subset of density 1. In the current paper, we extend this result in three different ways: The degrees of such sets A are precisely the nonlow c.e. degrees. There is a c.e. set A of density 1 with no computable subset of nonzero density. There is a (...) c.e. set A of density 1 such that every subset of A of density 1 is of high degree. We also study the extent to which c.e. sets A can be approximated by their computable subsets B in the sense that A\B has small density. There is a very close connection between the computational complexity of a set and the arithmetical complexity of its density and we characterize the lower densities, upper densities and densities of both computable and computably enumerable sets. We also study the notion of "computable at density r" where r is a real in the unit interval. Finally, we study connections between density and classical smallness notions such as immunity, hyperimmunity, and cohesiveness. (shrink)

For [Formula: see text], the coarse similarity class of A, denoted by [Formula: see text], is the set of all [Formula: see text] such that the symmetric difference of A and B has asymptotic density 0. There is a natural metric [Formula: see text] on the space [Formula: see text] of coarse similarity classes defined by letting [Formula: see text] be the upper density of the symmetric difference of A and B. We study the metric space of coarse similarity classes (...) under this metric, and show in particular that between any two distinct points in this space there are continuum many geodesic paths. We also study subspaces of the form [Formula: see text] where [Formula: see text] is closed under Turing equivalence, and show that there is a tight connection between topological properties of such a space and computability-theoretic properties of [Formula: see text]. We then define a distance between Turing degrees based on Hausdorff distance in the metric space [Formula: see text]. We adapt a proof of Monin to show that the Hausdorff distances between Turing degrees that occur are exactly 0, [Formula: see text], and 1, and study which of these values occur most frequently in the senses of Lebesgue measure and Baire category. We define a degree a to be attractive if the class of all degrees at distance [Formula: see text] from a has measure 1, and dispersive otherwise. In particular, we study the distribution of attractive and dispersive degrees. We also study some properties of the metric space of Turing degrees under this Hausdorff distance, in particular the question of which countable metric spaces are isometrically embeddable in it, giving a graph-theoretic sufficient condition for embeddability. Motivated by a couple of issues arising in the above work, we also study the computability-theoretic and reverse-mathematical aspects of a Ramsey-theoretic theorem due to Mycielski, which in particular implies that there is a perfect set whose elements are mutually 1-random, as well as a perfect set whose elements are mutually 1-generic. Finally, we study the completeness of [Formula: see text] from the perspectives of computability theory and reverse mathematics. (shrink)

We classify the asymptotic densities of the sets according to their level in the Ershov hierarchy. In particular, it is shown that for, a real is the density of an n‐c.e. set if and only if it is a difference of left‐ reals. Further, we show that the densities of the ω‐c.e. sets coincide with the densities of the sets, and there are ω‐c.e. sets whose density is not the density of an n‐c.e. set for any.

Paul E. Griffiths argues that most research on the emotions has been as misguided as Aristotelian efforts to study "superlunary objects" - objects...

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)

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)

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)

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)

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.

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)

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)

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)

An investigation is presented in which a computer simulation model (DIAGNOSER) is used to develop and test predictions for behavior of subjects in a task of medical diagnosis. The first experiment employed a process‐tracing methodology in order to compare hypothesis generation and evaluation behavior of DIAGNOSER with individuals at different levels of expertise (students, trainees, experts). A second experiment performed with only DIAGNOSER identified conditions under which errors in reasoning in the first experiment could be related to interpretation of specific (...) data items. Predictions derived from DIAGNOSER's performance were tested in a third experiment with a new sample of subjects. Data from the three experiments indicated that (1) form of diagnostic reasoning was similar for all subjects trained in medicine and for the simulation model, (2) substance of diagnostic reasoning employed by the simulation model was parable with that of the more expert subjects, and (3) errors in subjects' reasoning were attributable to deficiencies in disease knowledge and the interpretation of specific patient data cues predicted by the simulation model. (shrink)

Religion, reason, and the enchanted public sphere -- Minor protest(ant)s: Cohen and German-Jewish liberalism -- The dialectic of enchantment: science, religion, and secular reasoning -- Rights, religion, and race: Cohen's ethical socialism and the specter of anti-Semitism -- Enchanted reasoning: self-reflexive religion and minority -- Some minor reflections of enchantment.

Human experts are the source of knowledge required to develop computer systems that perform at an expert level. Human beings are not, however, able to reliably express what they know. As a result, experts often develop non-authentic accounts of their own expertise. These accounts, here termed reconstructed methods of reasoning, lead to computer systems that perform at a high level of proficiency but have the disadvantage that they often do not reflect the heuristics and processing constraints of a system user. (...) Reconstructed methods of reasoning are compared with authentic methods derived from the study of expert human behavior. Tests are proposed to establish the authenticity of reasoning methods and examples from medical diagnosis are used to illustrate how authentic methods of reasoning can be incorporated into an expert computer system. CiteULike Connotea Del.icio.us What's this? (shrink)

Psychopathy fascinates. Modernist writers construct out of it an image of alienated individualism pursuing the moment, killing they know not why, exploiting in passing, troubled, if troubled at all, not by guilt, but by perplexity (Camus 1989; Gide 1995; Mailer 1957; Musil 1996). Psychiatrists and psychologists—even those who should know better—are drawn by it to take off into philosophical speculation about morality, evil, and the beast in man (Mullen 1992; Simon 1996). Philosophers succumb to the temptation of attempting to ground (...) speculation in the supposed facticity of psychopathy. -/- Psychopathy is a cultural construct with roots going back to the eighteenth century, but which only came to full flower over the last fifty years (Hare 1998; Lewis 1974). The currently fashionable constructions of psychopathy find wide acceptance among clinicians and academics. The problem is, however, whether the concept has connections that have been established to the behavior, psychopathology, or the structure and function of brain worthy of according even a modest level of scientific status. There is little point in basing an argument on some supposed scientific gold standard if what glitters is iron pyrites (fools' gold). -/- Neil Levy's opening paragraph contains the statement "Yet in other respects they seem quite irrational; so much so that the term moral insanity has sometimes been applied to them" (p. 129). This both asserts that there is a category "them," namely the psychopaths, and connects them to "moral insanity." Moral insanity entered the language of psychiatry when Pritchard chose to use the term to translate Pinel's category of mania sans deliré (Pritchard 1836). Pinel was attempting to conceptualize a range of disorders that bordered on insanity in the sense of severe disturbances of affect, judgment, and behavior, but that were not accompanied by hallucinations or delusions (Pinel 1798/1964). In today's terminology, the cases he described would probably fall into diagnostic groups, including major depression, bipolar disorder, epilepsy, and a range of personality disorders. A number of his more striking case histories involved antisocial and even murderous behavior, which probably reflected Pinel's role in assessing offenders for the criminal courts of Paris. Pritchard's use of the English word "moral" reflected an appeal first to its use at the time to designate something which was like or similar, but not identical (a usage the OED labels "vulgar"), and second moral in the sense of ethical, conforming to virtuous behavior. Anglophones seized on the latter meaning, although Pinel emphasized the former. Forty years later, Henry Maudsley, the most widely read psychiatrist of his generation, could assert that moral insanity was as real as Colour blindness, some people being Colour blind and some moral blind (Maudsley 1879). Moral insanity became connected variously to phrenology with its own bump over the underlying moral cortex, with the twisted genetics of degeneration, with atavistic theories of criminality, and with a range of disorders of brain from epilepsy to frontal lobe damage (Combed 1853; Ellis 1890; Pick 1989). Although it is anachronistic to use the terms "psychopathy" and "moral insanity" together, it is clear they occupied a similar social and psychiatric space, albeit in different era. This should caution against too ready acceptance of psychopathy which may turn out to be as empty and dangerous a conceptualization as moral insanity. Why dangerous? Dangerous to those labeled, because the morally insane and the moral imbeciles were placed in preventive detention in asylums and prisons, and even sterilized in some jurisdictions. Dangerous to society, because it gave a spurious scientific justification for viewing crime not as reflecting the social evils of deprivation, ignorance, and inequality but as the ravages of the born criminals. -/- Psychopaths are not, as Levy asserts, "(causally) responsible for … more than fifty percent of violent crime" (p. 129). A proportion of violent offenders, which varies widely between observers, are labeled psychopaths. This is often on the basis of Hare's psychopathy checklist, which is a subjective, albeit through training aspiring to be reproducible, and to some extent self-sustaining, evaluation system (Hare 1980, 2003). Part of the checklist gathers data on prior antisocial behavior; part constrains the examiner to subjectively estimate such matters as glibness and callousness, part requires judgments about whether the... (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)

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)

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)

Though Frege was interested primarily in reducing mathematics to logic, he succeeded in reducing an important part of logic to mathematics by defining relations in terms of functions. By contrast, Whitehead & Russell reduced an important part of mathematics to logic by defining functions in terms of relations (using the definite description operator). We argue that there is a reason to prefer Whitehead & Russell's reduction of functions to relations over Frege's reduction of relations to functions. There is an interesting (...) system having a logic that can be properly characterized in relational but not in functional type theory. This shows that relational type theory is more general than functional type theory. The simplification offered by Church in his functional type theory is an over-simplification: one can't assimilate predication to functional application.<br>. (shrink)

Encyclopedia entry on the concepts of adaptation and adaptationism.

Kenneth C. Schaffner's paper is an important contribution to the literature on behavioral genetics and on genetics in general. Schaffner has a long record of injecting real molecular biology into philosophical discussions of genetics. His treatments of the reduction of Mendelian to molecular genetics first drew philosophical attention to the problems of detail that have fuelled both anti-reductionism and more sophisticated models of theory reduction. An injection of molecular detail into discussions of genetics is particularly necessary at the present time, (...) when so many philosophers seem happy to discuss the philosophical and ethical implications of molecular biology using gene concepts derived from evolutionary biology ). Schaffner has long advocated the view that the philosophy of biology should be more than the philosophy of evolution. This paper shows how radically a picture of gene action derived from molecular biology undercuts the popular picture associated with a more evolutionary view of genes as units of heredity or as ‘difference-makers’ mediated by the ‘black box’ of development. (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.