There is widespread belief that connectionist networks are dramatically different from classical or symbolic models. However, connectionists rarely test this belief by interpreting the internal structure of their nets. A new approach to interpreting networks was recently introduced by Berkeley et al. (1995). The current paper examines two implications of applying this method: (1) that the internal structure of a connectionist network can have a very classical appearance, and (2) that this interpretation can provide a cognitive theory that cannot be (...) dismissed as a mere implementation. (shrink)

We report on the deliberations of an interdisciplinary group of experts in science, law, and philosophy who convened to discuss novel ethical and policy challenges in stem cell research. In this report we discuss the ethical and policy implications of safety concerns in the transition from basic laboratory research to clinical applications of cell-based therapies derived from stem cells. Although many features of this transition from lab to clinic are common to other therapies, three aspects of stem cell biology pose (...) unique challenges. First, tension regarding the use of human embryos may complicate the scientific development of safe and effective cell lines. Second, because human stem cells were not developed in the laboratory until 1998, few safety questions relating to human applications have been addressed in animal research. Third, preclinical and clinical testing of biologic agents, particularly those as inherently complex as mammalian cells, present formidable challenges, such as the need to develop suitable standardized assays and the difficulty of selecting appropriate patient populations for early phase trials. We recommend that scientists, policy makers, and the public discuss these issues responsibly, and further, that a national advisory committee to oversee human trials of cell therapies be established. **NB we did not reccommend a NAC, we think it might be appropriate**. (shrink)

If stem cell-based therapies are developed, we will likely confront a difficult problem of justice: for biological reasons alone, the new therapies might benefit only a limited range of patients. In fact, they might benefit primarily white Americans, thereby exacerbating long-standing differences in health and health care.

As initially envisioned, Gödel's Collected Works were to include transcriptions of material from his mathematical workbooks. In the end that material, as well as some other manuscript items from Gödel's Nachlass, had to be left out. This note describes some of the unpublished items in the Nachlass that are likely to attract the notice of scholars and surveys the extent of shorthand transcription efforts undertaken hitherto. Some examples of sources outside Gödel's Nachlass that may be of interest to Gödel scholars (...) are also indicated. (shrink)

One new tradition that has emerged from early research on autonomous robots is embodied cognitive science. This paper describes the relationship between embodied cognitive science and a related tradition, synthetic psychology. It is argued that while both are synthetic, embodied cognitive science is antirepresentational while synthetic psychology still appeals to representations. It is further argued that modern connectionism offers a medium for conducting synthetic psychology, provided that researchers analyze the internal representations that their networks develop. The paper then provides a (...) detailed example of the synthetic approach by showing how the construction (and subsequent analysis) of a connectionist network can be used to contribute to a theory of how humans solve Piaget's classic balance scale task. (shrink)

According to several commentators, Kurt Godel's incompleteness discoveries were assimilated promptly and almost without objection by his contemporaries - - a circumstance remarkable enough to call for explanation. Careful examination reveals, however, that there were doubters and critics, as well as defenders and rival claimants to priority. In particular, the reactions of Carnap, Bernays, Zermelo, Post, Finsler, and Russell, among others, are considered in detail. Documentary sources include unpublished correspondence from Godel's Nachlass.

PDP networks that use nonmonotonic activation functions often produce hidden unit regularities that permit the internal structure of these networks to be interpreted (Berkeley et al., 1995; McCaughan, 1997; Dawson, 1998). In particular, when the responses of hidden units to a set of patterns are graphed using jittered density plots, these plots organize themselves into a set of discrete stripes or bands. In some cases, each band is associated with a local interpretation. On the basis of these observations, Berkeley (...) (2000) has suggested that these bands are both subsymbolic and symbolic in nature, and has used the analysis of one network to support the claim that there are fewer differences between symbols and subsymbols than one might expect. We suggest below that this conclusion is premature. First, in many cases the local interpretation of each band is difficult to relate to the interpretation of a network's response; a more appropriate relationship only emerges when a band associated with one hidden unit is considered in the context of other bands associated with other hidden units (i.e., interpretations of distributed representations are more useful than interpretations of local representations). Second, the content that a band designates to an external observer (i.e., the interpretation assigned to a band by the researcher) can be quite different from the content that a band designates to the output units of the network itself.. We use two different network simulations – including the one described by Berkeley (2000) – to illustrate these points. We conclude that current evidence involving interpretations of nonmonotonic PDP networks actually illustrates the differences between symbolic and subsymbolic processing. (shrink)

A colleague’s personal recollections of Jean van Heijenoort’s contributions to the editing of volumes I–III of Gödel’s Collected Works and of his interactions with the other editors.

One new tradition that has emerged from early research on autonomous robots is embodied cognitive science. This paper describes the relationship between embodied cognitive science and a related tradition, synthetic psychology. It is argued that while both are synthetic, embodied cognitive science is antirepresentational while synthetic psychology still appeals to representations. It is further argued that modern connectionism offers a medium for conducting synthetic psychology, provided that researchers analyze the internal representations that their networks develop. The paper then provides a (...) detailed example of the synthetic approach by showing how the construction of a connectionist network can be used to contribute to a theory of how humans solve Piaget's classic balance scale task. (shrink)

Schyns et al.'s (1998) target article raises a conflict between the need for a fixed functional architecture in an explanatory cognitive science and the need for a system to learn to detect new features. This conflict can be resolved by avoiding the scope slip in which properties of objects are erroneously viewed as being properties of their representations.

How might artificial neural networks (ANNs) inform cognitive science? Often cognitive scientists use ANNs but do not examine their internal structures. In this paper, we use ANNs to explore how cognition might represent musical properties. We train ANNs to classify musical chords, and we interpret network structure to determine what representations ANNs discover and use. We find connection weights between input units and hidden units can be described using Fourier phase spaces, a representation studied in musical set theory. We find (...) the total signal coming through these weighted connection weights is a measure of the similarity between two Fourier structures: the structure of the hidden unit's weights and the structure of the stimulus. This is surprising because neither of these Fourier structures is computed by the hidden unit. We then show how output units use such similarity measures to classify chords. However, we also find different types of units—units that use different activation functions—use this similarity measure very differently. This result, combined with other findings, indicates that while our networks are related to the Fourier analysis of musical sets, they do not perform Fourier analyses of the kind usually described in musical set theory. Our results show Fourier representations of music are not limited to musical set theory. Our results also suggest how cognitive psychologists might explore Fourier representations in musical cognition. Critically, such theoretical and empirical implications require researchers to understand how network structure converts stimuli into responses. (shrink)

This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of (...) justifying the use of reciprocity through appeal to different moral and political theoretical traditions. We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others. We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally. (shrink)

Libertarians such as J.R. Lucas have abandoned traditional Christian doctrines because they cannot reconcile them with the freedom of the will. Traditional Christian thinkers such as Augustine have repudiated libertarianism because they cannot reconcile it with the dogmas of the Faith. In Free Will and the Christian Faith, W.S. Anglin demonstrates that free will and traditional Christianity are ineed compatible. He examines, and solves, puzzles about the relationships between free will and omnipotence, omniscience, and God's goodness, using the idea of (...) free will to answer the question of why God allows evil, and presenting arguments that link free will to eternal life and to the nature of revelation. Topics covered include the meaning of life, the soul and Lesbegue measure, and strategies for discerning the voice of God. (shrink)

The success of the Human Genome Project has prompted interest in advancing the nascent field of exposomics. The exposome, which is dynamic and variable and changes over time, consists of all the internal and external exposures an individual has over a lifetime beginning with the prenatal period and early childhood. Efforts are underway to decipher the human epigenome by identifying the effects of all deleterious environmental exposures according to duration of exposure and time period. In this article, we argue that (...) the deciphering of the human exposome should be accompanied by sustained efforts to address the ethical, social and legal implications (ELSI) of exposomics. This will require financial investments from the National Institutes of Health (NIH), the European Union and other public and private funding agencies, analogous to support provided by NIH to address ELSI issues in genomics. (shrink)

by W. S. F. Pickering Durkheim's sociological approach to morals and moral systems has always aroused considerable interest, be it by way of criticism or ...

Heidegger’s characterization of Dasein as Being-in-the-world suggests a natural relation to environmental philosophy. Among environmentalists, however, closer inspection must raise alarm, both since Heidegger’s approach is in some senses inescapably anthropocentric and since Dasein discovers its environment through its usability, serviceability, and accessibility. Yet Heidegger does not simply adopt a traditionally modern, instrumental view. The conditions under which the environment appears imply neither that the environment consists only of tools, nor that what is true of the parts is also true (...) of the whole, nor that an orientation to use—where appropriate—precludes any other orientation. Heidegger’s anthropocentric commitments thus do not rule out the possibility of a non-instrumental perspective on the natural world. (shrink)

Although other quasi-Kantian theories have been adapted, Jürgen Habermas’s discourse theory has been largely ignored in discussions of environmental ethics. Indeed on some versions of what an environmental philosophy must entail, Habermas’s anthropocentric approach must be disqualified from the start. Yet, there are some environmentally friendly implications of his discourse theory. They may not give us everything we would wish, but in the contemporary political context we must treasure any moral theory that can draw on the still-extensive theoretical and political (...) resources of liberalism. (shrink)

By arguing that his use of representations at the core of Durkheim's sociological thought, this book makes a unique contribution to Durkheimian studies which have recently been dominated by postivist and functionalist interpretaions, and reveals a thinker very much in tune with contemporary developments in philosophy, linguistics and sociology.