Linear structural equation models (SEMs) are widely used in sociology, econometrics, biology, and other sciences. A SEM (without free parameters) has two parts: a probability distribution (in the Normal case specified by a set of linear structural equations and a covariance matrix among the “error” or “disturbance” terms), and an associated path diagram corresponding to the functional composition of variables specified by the structural equations and the correlations among the error terms. It is often thought that the path diagram is (...) nothing more than a heuristic device for illustrating the assumptions of the model. However, in this paper, we will show how path diagrams can be used to solve a number of important problems in structural equation modelling. (shrink)

It has been shown in Spirtes(1995) that X and Y are d-separated given Z in a directed graph associated with a recursive or non-recursive linear model without correlated errors if and only if the model entails that ρXY.Z = 0. This result cannot be directly applied to a linear model with correlated errors, however, because the standard graphical representation of a linear model with correlated errors is not a directed graph. The main result of this paper is to show how (...) to associate a directed graph with a linear model L with correlated errors, and then use d-separation in the associated directed graph to determine whether L entails that a particular partial correlation is zero. (shrink)

Whenever the use of non-experimental data for discovering causal relations or predicting the outcomes of experiments or interventions is contemplated, two difficulties are routinely faced. One is the problem of latent variables, or confounders: factors influencing two or more measured variables may not themselves have been measured or recorded. The other is the problem of sample selection bias: values of the variables or features under study may themselves influence whether a unit is included in the data sample.

In order to create sustainable health systems, many countries are introducing ways to prioritize health services underpinned by a process of health technology assessment. While this approach requires technical judgments of clinical effectiveness and cost-effectiveness, these are embedded in a wider set of social (societal) value judgments, including fairness, responsiveness to need, non-discrimination and obligations of accountability and transparency. Implementing controversial decisions faces legal, political and public challenge. To help generate acceptance for the need for health prioritization and the resulting (...) decisions, the purpose of this paper is to develop a novel way of encouraging key stakeholders, especially patients and the public, to become involved in the prioritization process. (shrink)

Understanding everyday behavior relies heavily upon understanding our ability to improvise, how we are able to continuously anticipate and adapt in order to coordinate with our environment and others. Here we consider the ability of musicians to improvise, where they must spontaneously coordinate their actions with co-performers in order to produce novel musical expressions. Investigations of this behavior have traditionally focused on describing the organization of cognitive structures. The focus, here, however, is on the ability of the time-evolving patterns of (...) inter-musician movement coordination as revealed by the mathematical tools of complex dynamical systems to provide a new understanding of what potentiates the novelty of spontaneous musical action. We demonstrate this approach through the application of cross wavelet spectral analysis, which isolates the strength and patterning of the behavioral coordination that occurs between improvising musicians across a range of nested time-scales. Revealing the sophistication of the previously unexplored dynamics of movement coordination between improvising musicians is an important step towards understanding how creative musical expressions emerge from the spontaneous coordination of multiple musical bodies. (shrink)

It is well known that there may be many causal explanations that are consistent with a given set of data. Recent work has been done to represent the common aspects of these explanations into one representation. In this paper, we address what is less well known: how do the relationships common to every causal explanation among the observed variables of some DAG process change in the presence of latent variables? Ancestral graphs provide a class of graphs that can encode conditional (...) independence relations that arise in DAG models with latent and selection variables. In this paper we present a set of orientation rules that construct the Markov equivalence class representative for ancestral graphs, given a member of the equivalence class. These rules are sound and complete. We also show that when the equivalence class includes a DAG, the equivalence class representative is the essential graph for the said DAG. (shrink)

Despite the ubiquity of inner speech in our mental lives, methods for objectively assessing inner speech capacities remain underdeveloped. The most common means of assessing inner speech is to present participants with tasks requiring them to silently judge whether two words rhyme. We developed a version of this task to assess the inner speech of a population of patients with aphasia and corresponding language production deficits. As expected, patients’ performance on the silent rhyming task was severely impaired relative to controls. (...) More surprisingly, however, patients’ performance on this task did not correlate with their performance on a variety of other standard tests of overt language abilities. In particular, patients who were generally unimpaired in their abilities to overtly name objects during confrontation naming tasks, and who could reliably judge when two words spoken to them rhymed, were still severely impaired (relative to controls) at completing the silent rhyme task. This seems to suggest that inner speech was more severely impaired in these patients than outer speech. However, these results should also cause us to critically reflect on the relation between inner speech and silent rhyme judgments more generally. (shrink)

This paper introduces a class of graphical independence models that is closed under marginalization and conditioning but that contains all DAG independence models. This class of graphs, called maximal ancestral graphs, has two attractive features: there is at most one edge between each pair of vertices; every missing edge corresponds to an independence relation. These features lead to a simple parameterization of the corresponding set of distributions in the Gaussian case.

In recent years, language has been shown to play a number of important cognitive roles over and above the communication of thoughts. One hypothesis gaining support is that language facilitates thought about abstract categories, such as democracy or prediction. To test this proposal, a novel set of semantic memory task trials, designed for assessing abstract thought non-linguistically, were normed for levels of abstractness. The trials were rated as more or less abstract to the degree that answering them required the participant (...) to abstract away from both perceptual features and common setting associations corresponding to the target image. The normed materials were then used with a population of people with aphasia to assess the relationship of abstract thought to language. While the language-impaired group with aphasia showed lower overall accuracy and longer response times than controls in general, of special note is that their response times were significantly longer as a function of a trial’s degree of abstractness. Further, the aphasia group’s response times in reporting their degree of confidence (a separate, metacognitive measure) were negatively correlated with their language production abilities, with lower language scores predicting longer metacognitive response times. These results provide some support for the hypothesis that language is an important aid to abstract thought and to metacognition about abstract thought. (shrink)

To give priority to the young over the elderly has been labelled ‘ageism’. People who express ‘ageist’ preferences may feel that, all else equal, an individual has greater right to enjoy additional life years the fewer life years he or she has already had. We shall refer to this as egalitarian ageism. They may also emphasise the greater expected duration of health benefits in young people that derives from their greater life expectancy. We may call this utilitarian ageism. Both these (...) forms of ageism were observed in an empirical study of social preferences in Australia. The study lends some support to the assumptions in the QALY approach that duration of benefits, and hence old age, should count in prioritising at the budget level in health care. (shrink)

To give priority to the young over the elderly has been labelled ‘ageism’. People who express ‘ageist’ preferences may feel that, all else equal, an individual has greater right to enjoy additional life years the fewer life years he or she has already had. We shall refer to this asegalitarian ageism. They may also emphasise the greater expected duration of health benefits in young people that derives from their greater life expectancy. We may call thisutilitarian ageism. Both these forms of (...) ageism were observed in an empirical study of social preferences in Australia. The study lends some support to the assumptions in the QALY approach that duration of benefits, and hence old age, should count in prioritising at the budget level in health care. (shrink)

This study examines the relation of language use to a person’s ability to perform categorization tasks and to assess their own abilities in those categorization tasks. A silent rhyming task was used to confirm that a group of people with post-stroke aphasia (PWA) had corresponding covert language production (or “inner speech”) impairments. The performance of the PWA was then compared to that of age- and education-matched healthy controls on three kinds of categorization tasks and on metacognitive self-assessments of their performance (...) on those tasks. The PWA showed no deficits in their ability to categorize objects for any of the three trial types (visual, thematic, and categorial). However, on the categorial trials, their metacognitive assessments of whether they had categorized correctly were less reliable than those of the control group. The categorial trials were distinguished from the others by the fact that the categorization could not be based on some immediately perceptible feature or on the objects’ being found together in a type of scenario or setting. This result offers preliminary evidence for a link between covert language use and a specific form of metacognition. (shrink)

The paper is concerned with the potential or actual impact that free-market governmental principles and policies might have, or might have had, in helping to create a more crisis-prone world. It is concerned with organizationally-induced crises where organizations and their environment interact to create disasters. The nature of the crisis-prone organization is discussed in the context of the relevant management literature. It is argued that the disastrous interaction of such an organization with its environment is promoted by a laisser-faire attitude (...) on the part of the authorities. This is illustrated in the context of two recent British disasters involving the King''s Cross Underground fire and the sinking of the Herald of Free Enterprise. (shrink)

Cook et al. reported a 97% scientific consensus on anthropogenic global warming (AGW), based on a study of 11,944 abstracts in peer-reviewed science journals. Powell claims that the Cook et al. methodology was flawed and that the true consensus is virtually unanimous at 99.99%. Powell’s method underestimates the level of disagreement because it relies on finding explicit rejection statements as well as the assumption that abstracts without a stated position endorse the consensus. Cook et al.’s survey of the papers’ authors (...) revealed that papers may express disagreement with AGW despite the absence of a rejection statement in the abstract. Surveys reveal a large gap between the public perception of the degree of scientific consensus on AGW and reality. We argue that it is the size of this gap, rather than the small difference between 97% and 99.99%, that matters in communicating the true state of scientific opinion to the public. (shrink)

Thomas Richardson and Peter Spirtes. Parameterizing and Scoring Mixed Ancestral Graphs.

Thomas Richardson and Peter Spirtes. Scoring Ancestral Graph Models.

The authors take a hard and critical look at the gospel of market economy and its long-term consequences. They examine its major assumptions, its major policy imperatives and their consequen tial impacts on ecology, society, human beings and organizations. The paper urges a redefinition of this dominant paradigm of today, and advocates the need for it to be subjected to the wider considerations of a caring and ecologically sound belief system. The appendices offer descriptive accounts of actual cases which show (...) the real and repeated crisis-producing potential of this paradigm. (shrink)

What proportion of available healthcare funds should be allocated to hip replacement operations and what proportion to psychiatric care? What proportion should go to cardiac patients and what to newborns in intensive care? What proportion should go to preventative medicine and what to treating existing conditions? In general, how should limited healthcare resources be distributed If not all demands can be met?

Sober (1992) has recently evaluated Brandon's (1982, 1990; see also 1985, 1988) use of Salmon's (1971) concept of screening-off in the philosophy of biology. He critiques three particular issues, each of which will be considered in this discussion.

Musical improvisation is a natural case of human pattern formation, and Walton and colleagues investigate the way that different contextual constraints affect patterns of improvisation and their aesthetic quality. The authors find that coordination patterns are more diversified between two musicians when the musical space in which to improvise is relatively more constrained. They also find that listeners experience more diversified, complementary patterns between musicians as more enjoyable and harmonious.

This paper describes the application of eight statistical and machine-learning methods to derive computer models for predicting mortality of hospital patients with pneumonia from their findings at initial presentation. The eight models were each constructed based on 9847 patient cases and they were each evaluated on 4352 additional cases. The primary evaluation metric was the error in predicted survival as a function of the fraction of patients predicted to survive. This metric is useful in assessing a model’s potential to assist (...) a clinician in deciding whether to treat a given patient in the hospital or at home. We examined the error rates of the models when predicting that a given fraction of patients will survive. We examined survival fractions between 0.1 and 0.6. Over this range, each model’s predictive error rate was within 1% of the error rate of every other model. When predicting that approximately 30°K of the patients will survive, all the models have an error rate of less than 1.5%. The models are distinguished more by the number of variables and parameters that they contain than by their error rates; these differences suggest which models may be the most amenable to future implementation as paper-based guidelines. (shrink)

By registering different health benefits on a common scale, CEA allows us to assess the relative social importance of different health care interventions and opens the way for the allocation decisions of health care policy. If it is really to be effective, however, CEA must be recalibrated so that it better reflects some of our widely held beliefs about the merits of different kinds of treatment.

By registering different health benefits on a common scale, CEA allows us to assess the relative social importance of different health care interventions and opens the way for the allocation decisions of health care policy. If it is really to be effective, however, CEA must be recalibrated so that it better reflects some of our widely held beliefs about the merits of different kinds of treatment.

Peter Abelard (1079–1142 ce) was the most wide‐ranging philosopher of the twelfth century. He quickly established himself as a leading teacher of logic in and near Paris shortly after 1100. After his affair with Heloise, and his subsequent castration, Abelard became a monk, but he returned to teaching in the Paris schools until 1140, when his work was condemned by a Church Council at Sens. His logical writings were based around discussion of the “Old Logic”: Porphyry's Isagoge, aristotle'S Categories (...) and On Interpretation and boethius'S textbook on topical inference. They comprise a freestanding Dialectica (“Logic”; probably c.1116), a set of commentaries (known as the Logica [Ingredientibus], c. 1119) and a later (c. 1125) commentary on the Isagoge (Logica Nostrorum Petititoni Sociorum or Glossulae). In a work Abelard called his Theologia, issued in three main versions (between 1120 and c.1134), he attempted a logical analysis of trinitarian relations and explored the philosophical problems surrounding God's claims to omnipotence and omniscience. The Collationes (“Debates,” also known as “Dialogue between a Christian, a Philosopher and a Jew”; probably c.1130) present a rational investigation into the nature of the highest good, in which the Christian and the Philosopher (who seems to be modeled on a philosopher of pagan antiquity) are remarkably in agreement. The unfinished Scito teipsum (“Know thyself,” also known as the “Ethics”; c.1138) analyses moral action. (shrink)

The contribution of this book to the field of reconciliation is both theoretical and practical, recognizing that good theory guides effective practice and practice is the ground for compelling theory. Using a Girardian hermeneutic as a starting point, a new conceptual Gestalt emerges in these essays, one not fully integrated in a formal way but showing a clear understanding of some of the challenges and possibilities for dealing with the deep divisions, enmity, hatred, and other effects of violence. By situating (...) discourse about reconciliation within the context of Girardian thought, it becomes clear that like Peter who vowed he would never deny Jesus but ended up doing it three times any of us is susceptible to the siren call of angry resentment and retaliation. It is with a profound awareness of the power of violence that the emergence of mimetic discourse around reconciliation takes on particular urgency.". (shrink)

The contribution of this book to the field of reconciliation is both theoretical and practical, recognizing that good theory guides effective practice and practice is the ground for compelling theory. Using a Girardian hermeneutic as a starting point, a new conceptual Gestalt emerges in these essays, one not fully integrated in a formal way but showing a clear understanding of some of the challenges and possibilities for dealing with the deep divisions, enmity, hatred, and other effects of violence.

This symposia-papers volume is the second volume of essays from the PSA 2008 program. The vast majority of the work in putting together this volume fell to the program committee. The members of this committee began the adjudication process with over 200 submitted papers and went through two rounds of selection, first for the program and then for this volume. Throughout, they all worked diligently and in good humor. So, I would like to thank Ken Aizawa, Rachel Ankeny, Davis Baird, (...) Paul Bartha, Anjan Chakravartty, Hasok Chang, Sharyn Clough, Carla Fehr, Peter Godfrey-Smith, Brad Monton, Mark Risjord, Laura Ruetsche, Kyle Stanford, Friedrich Steinle, and Peter Vranas. In addition to papers from symposia presented at PSA 2008, we hope the selection of symposia reveals the widening range of philosophical expertise within the PSA. (shrink)

This contributed-papers volume is the first volume of essays from the PSA 2008 program. The vast majority of the work in putting together this volume fell to the program committee. The members of this committee began the adjudication process with over 200 submitted papers and went through two rounds of selection, first for the program and then for this volume. Throughout, they all worked diligently and in good humor. So, I would like to thank Ken Aizawa, Rachel Ankeny, Davis Baird, (...) Paul Bartha, Anjan Chakravartty, Hasok Chang, Sharyn Clough, Carla Fehr, Peter Godfrey-Smith, Brad Monton, Mark Risjord, Laura Ruetsche, Kyle Stanford, Friedrich Steinle, and Peter Vranas. (shrink)

This highly multidisciplinary collection discusses an increasingly important topic among scholars in science and technology studies: objectivity in science. It features eleven essays on scientific objectivity from a variety of perspectives, including philosophy of science, history of science, and feminist philosophy. Topics addressed in the book include the nature and value of scientific objectivity, the history of objectivity, and objectivity in scientific journals and communities. Taken individually, the essays supply new methodological tools for theorizing what is valuable in the pursuit (...) of objective knowledge and for investigating its history. The essays offer many starting points, while suggesting new avenues of research. Taken collectively, the essays exemplify the very virtues of objectivity that they theorize—in reading them together, the reader can sense various anxieties about the dangerously subjective in our age and locate commonalities of concern as well as differences of approach. As a result, the volume offers an expansive vision of a research community seeking a communal understanding of its own methods and its own epistemic anxieties, struggling to enunciate the key problems of knowledge of our time and offer insight into how to overcome them. -/- (Contributors: Alex Csiszar, Scott Edgar, Peter Galison, Ian Hacking, Sandra Harding, Moira Howes, Paolo Savoia, Judy Segal, Joan Steigerwald, and Alison Wylie). (shrink)

In Aaron and Bachalo's work, Doctor Stephen Strange exemplifies the characteristics and methods of the natural philosophers in clashes with his mystical enemies, Lord Imperator and the Empirikul. It's easy to be distracted by Doctor Strange's fancy spells, unique job title, or flashy cape, but we should also recognize that he is a Sorcerer Supreme, who demonstrates both discipline and intellect. Like the historical philosopher‐scientists, Doctor Strange studies metaphysics and its relationship to the physical world. When intellectuals began to challenge (...) Aristotle's teleological world‐view, they faced opposition from both the Catholic Church, who found Aristotle's views consistent with scripture, and the scientific community. Historian Peter Dear's book Revolutionizing the Sciences helps situate the work of ancient philosophers, like Aristotle, in the context of the history of the scientific revolution. (shrink)

J. H. van 't Hoff's 1874 Dutch pamphlet, in which he proposed the spatial arrangement of atoms in a molecule, is one of the most significant documents in the history of chemistry. This essay presents a new narrative of Van 't Hoff's early life and places the appearance of the pamphlet within the context of the 'second golden age' of Dutch science. We argue that the combination of the reformed educational system in The Netherlands, the emergence of graphical molecular modelling (...) within the theoretical and practical culture of chemistry during the 1860s and 1870s, as well as Van 't Hoff's own personal research trajectory, formed the background to his unprecedented attribution of spatial meaning to the traditional concept of atomic 'arrangement'. We also present a new English translation of the pamphlet, for we have found that the existing translation, published by G. M. Richardson in 1901, contains many errors, changes and omissions. The new version offers a more accurate rendition in English of Van 't Hoff's style and argument. (shrink)

AT the conclusion of his 1962 letter to William Richardson, Heidegger speaks about language and the thinking of Being. ‘In proportion to the intrinsically manifold matter of Being and Time all words which give this matter utterance…are always ambiguous. Only a manifold thought succeeds in uttering the heart of this matter in a way that corresponds with it. This manifold thought requires, however, not a new language but a transformed relationship to the essence of the old one’.

On pages 490-491, in describing the results of Experiment 2, the authors state that out of a total of 3840 responses, only 355 (or 9%) fell outside the response deadlines. In fact, the total number of responses in Experiment 2 was 3200 and so the 355 responses represented 11%, not 9%, of the total. This error has no other implications. The authors are grateful to Peter Graf (personal communication, March 12, 2000) for pointing out the error.