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.

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)

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

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)

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)

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)

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)

Many of the most important properties of human groups – including properties that may give one group an evolutionary advantage over another – are properly defined only at the level of group organization. Yet at present, most work on the evolution of culture has focused solely on the transmission of individual-level traits. I propose a conceptual extension of the theory of cultural evolution, particularly related to the evolutionary competition between cultural groups. The key concept in this extension is the emergent (...) group-level trait. This type of trait is characterized by the structured organization of differentiated individuals and constitutes a unit of selection that is qualitatively different from selection on groups as defined by traditional multilevel selection theory. As a corollary, I argue that the traditional focus on cooperation as the defining feature of human societies has missed an essential feature of cooperative groups. Traditional models of cooperation assume that interacting with one cooperator is equivalent to interacting with any other. However, human groups involve differential roles, meaning that receiving aid from one individual is often preferred to receiving aid from another. In this target article, I discuss the emergence and evolution of group-level traits and the implications for the theory of cultural evolution, including ramifications for the evolution of human cooperation, technology, and cultural institutions, and for the equivalency of multilevel selection and inclusive fitness approaches. (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)

In this dissertation, I argue that psychology is central to the meaning and purposes of Nietzsche's work. Rather than suspending all ethical judgment or upholding a universal morality, Nietzsche offers models of psychological strength: the teaching of eternal return, the ethics of enemy love, laughter, and his own writing. In Nietzsche's models for psychological strength, my interpretation finds the basis for separating him from both those who find in Nietzsche the roots of totalitarian politics and those who find in Nietzsche's (...) view of the self a playful creativity they suppose supports liberal individualism. ;Through the deficient model of the free spirit of Beyond Good and Evil, I examine the role of honesty in Nietzsche's work and its confrontation with the need for appearances and masks. Through a careful examination of Thus Spoke Zarathustra, I explore the search for a human meaning for the earth, the problem of revenge, the psychological importance of the teaching of eternal return, and its ethical implications. While Zarathustra begins by teaching the Uebermensch, this empty teaching of creativity gives way to the problem of revenge and the need for a new form of redemption. The teaching of eternal returns seeks to overcome the problem of revenge by reconciling the will with the past, freedom with necessity, and the desire for immortality with the temporal character of human life. I argue that the psychological meaning of eternal return takes priority to its cosmological claims and that this teaching encourages an ethics of enemy-love, internalized as self-overcoming. Nietzsche's use of comedy exhibits the possibility of the internal split that combines the capacity for self-knowledge with the possibility of self-overcoming. I argue that Nietzsche stands above his character Zarathustra who teaches doctrines and that his writing manifests such an internalized split, the self-challenging that makes possible philosophy that does not collapse into dogmatism. His autobiographical Ecce Homo takes a comic form to encourage this split, appeal to a democratic audience, and to exemplify Nietzsche's distance above his own characters and their doctrines. Nietzsche thus succeeds where his character fails by offering indirect communication that makes possible the partial connection necessary for political life and by maintaining the distance from his doctrines necessary for new challenges and continued thought. (shrink)

The relationship between individuals’ creativity and their ethical ideologies appears to be complex. Applying Forsyth’s (1980, 1992) personal moral philosophy model which consists of two independent ethical ideology dimensions, idealism and relativism, we hypothesized and found support for a positive relationship between creativity and relativism. It appears that creative people are less likely than non-creative people to follow universal rules in their moral decision making. However, contrary to our hypothesis and the general stereotype that creative people are less caring about (...) others, we found a positive relationship between creativity and idealism. These findings indicate that highly creative people are likely to be what Forsyth called “situationists,” individuals with both an ethic of caring and a pragmatic moral decision-making style. The finding that creative individuals tend to be situationists, and particularly that they tend to be high in idealism, appears to refute the line of reasoning that argues for a “creative personality” characterized in part by social insensitivity. Understanding the relationship between creativity and ethical ideologies has important implications for researchers, managers and teachers. (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)

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)

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)

This article discusses a serious problem in the way ethics is taught in journalism and mass communication programs. The study is based, in part, on a survey of 359 students who have had varied exposure to university journalism programs. The survey consisted of 87 questions that provided information on the demographics of the participants as well as an opportunity to respond to a series of 25 hypothetical ethical dilemmas. Results indicate that although respondents found most of the hypothetical situations to (...) be ethics violations, they often did not recognize the seriousness of the violations and did not know what to do when faced with those violations. (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)

The Ikhwan al-Safa (Brethren of Purity), the anonymous adepts of a tenth-century esoteric fraternity based in Basra and Baghdad, hold an eminent position in the history of science and philosophy in Islam due to the wide reception and assimilation of their monumental encyclopaedia, the Rasa'il Ikhwan al-Safa (Epistles of the Brethren of Purity). This compendium contains fifty-two epistles offering synoptic accounts of the classical sciences and philosophies of the age; divided into four classificatory parts, it treats themes in mathematics, logic, (...) natural philosophy, psychology, metaphysics, and theology, in addition to didactic fables. Epistles 32 to 36 comprise the first five treatises in the third division of the Rasa'il, on the sciences of the soul and intellect. Combining Islamic revelation with Hellenistic philosophy, the Ikhwan delineate herein their metaphysical system. Epistles 32 and 33 present adaptations of the Pythagorean doctrines, and of Neo-Platonist leitmotifs, whereby a numerical analogy is applied to the unique and transcendent God, or the One, from whom all existence emanates. Epistle 34 takes up the pervasive theme of the correspondence between microcosm and macrocosm, situating the human being as the central link between the celestial and terrestrial realms. In Epistle 35, we find an explanation of the intellectual faculties of the individual human soul, whose ultimate aim is ascension to the timeless reality of pure intellect. Finally, Epistle 36 presents itself as the astrological epistle par excellence of the Rasa'il; from the coming-to-be of worms, to the emergence of religions and empires, nothing in the sub-lunar sphere escapes the determining influence of the celestial cycles. (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)

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.

In lieu of an abstract, here is a brief excerpt of the content:I Am Not Sure?Paul E. LevinIt was a beautiful Friday morning, a few weeks into the summer. My schedule appeared lighter than usual and I even envisioned leaving work a bit early. Maybe a challenging bike ride before dinner. I was sitting in the chairman’s office having our weekly meeting. One of our junior faculty members called... he needed help. He was on call and a 32–year–old pregnant (...) woman with a displaced femoral neck fracture had just been transferred to our emergency department (ED). Ms. B tripped in her kitchen last evening. She was unable to stand and was brought to the local ED by ambulance.My colleague was concerned that he wouldn’t be able to successfully reduce the fracture. The long–term prognosis of the hip joint depended on a successful reduction of the femoral neck fracture. In addition, there was an ongoing debate in the orthopaedic literature related to the urgency of operative care to prevent osteonecrosis of the femoral head. I reviewed the x–rays, didn’t anticipate a problem and let him know that I would come to the operating room (OR) to assist. “No”, he responded, “I am not comfortable caring for this patient”. I immediately left the office, went to the hospital and assumed care of the patient. Clearly, my plans for a bike ride were gone, but I had the opportunity to help a woman in need of expert orthopaedic care.Ms. B had been admitted to the obstetrical service. She was a 32–year–old woman of Haitian descent who had recently immigrated to the United States. She had very limited English comprehension and her primary spoken languages were French and Creole. She was alone, in a hospital in a foreign country. She was 24 weeks pregnant with her first child and had no other co–morbidities. Her pregnancy had ben progressing uneventfully.When I first met Ms. B she was lying on a stretcher in an observation unit on the obstetrical floor. She appeared frightened. Two orthopaedic residents were present and obtaining consent for surgical repair of the hip. In their minds there was nothing to discuss, the patient had a displaced femoral neck fracture and needed to have surgery immediately. In their minds, no other options were available and obtaining consent would be straightforward. I introduced myself, sat down on a lab stool by the bed and began a conversation. I needed to meet the patient, understand who she was and discuss treatment. I am not sure that obtaining an informed consent is ever “straightforward” when [End Page 14] a doctor is explaining to a patient that they require emergency surgery. This discussion surely would not be easy or straightforward.We utilized a telephone interpretation service. Every question and response required the transfer of the handset between the patient and physician. Ms. B was in pain and frightened. She immediately expressed concern about her pregnancy and her baby. I arranged for her to meet all of the physicians who would possibly be involved in her care and the care of her baby. Each consultant could explain their area of expertise and potential involvement in the care of Ms. B and her child. She met and had an opportunity to talk with the obstetrician on call, a maternal fetal medicine (MFM) fellow and a neonatologist. I supplied the orthopaedic information. I explained the severity of the injury, the risks of osteonecrosis either with or without surgery as well as concerns over non–union and traumatic arthritis of the hip. Undoubtedly, in a healthy 32–year–old woman who wasn’t pregnant, early surgical intervention would be the most appropriate management in hopes of preserving a normal hip joint. We also discussed the possibility of treating her without surgery. She would be administered pain medication, which were known to be safe during pregnancy, and allowed to begin to ambulate with a walker or crutches. I explained potential problems without surgery and what options would be available to treat any problems that developed with her hip after the child was born. Of course, hip fractures in pregnant woman are very rare, and as a result treating a... (shrink)

Do the previous termviewpoint costsnext term incurred when naming rotated familiar objects arise during initial identification or during previous termconsolidation?next term To answer this question we employed an attentional blink (AB) task where two target objects appeared amongst a rapid stream of distractor objects. Our assumption was that while both targets and distractors undergo initial identification only targets are consolidated in a form that allows overt report. We presented line drawings of objects with a usual upright canonical orientation, and separately (...) manipulated the orientation of targets and distractors. In two experiments, targets were defined by colour, whereas in a third experiment they were defined by semantic category. Target 1 orientation influenced the AB, with objects rotated by 90° causing a larger second target deficit than upright and upside-down objects. However, distractor orientation did not affect the magnitude of the second target deficit, regardless of whether targets were defined by colour or semantic category. Taken together, these findings suggest that the visual representations involved in the preliminary recognition of familiar objects are previous termviewpointnext term-invariant and that previous termviewpoint costsnext term are incurred when these objects are consolidated for report. (shrink)