We share with Anderson & Lebiere (A&L) (and with Newell before them) the goal of developing a domain-general framework for modeling cognition, and we take seriously the issue of evaluation criteria. We advocate a more focused approach than the one reflected in Newell's criteria, based on analysis of failures as well as successes of models brought into close contact with experimental data. A&L attribute the shortcomings of our parallel-distributed processing framework to a failure to acknowledge a symbolic level (...) of thought. Our framework does acknowledge a symbolic level, contrary to their claim. What we deny is that the symbolic level is the level at which the principles of cognitive processing should be formulated. Models cast at a symbolic level are sometimes useful as high-level approximations of the underlying mechanisms of thought. The adequacy of this approximation will continue to increase as symbolic modelers continue to incorporate principles of parallel distributed processing. (shrink)

Features of gait are determined at multiple levels, from the selection of the gait itself (e.g. walk or run) through the specific parameters utilized (stride length, frequency, etc.) to the pattern of muscular excitation. The ultimate choices are neurally determined, but what is involved with that decision process? Human locomotion appears stereotyped not so much because the pattern is predetermined, but because these movement patterns are good solutions for providing movement utilizing the machinery available to the individual (the legs and (...) their requisite components). Under different circumstances the appropriate solution may differ broadly (different gait) or subtly (different parameters). Interpretation of the neural decision making process would benefit from understanding the influences that determine the selection of the appropriate solution in any set of circumstances, including that of normal conditions. In this review we survey an array of studies that point to energetic cost as a key input to the gait coordination system, and not just an outcome of the gait pattern implemented. We then use that information to rigorously define the construct proposed by Sparrow and Newell (1998) where the effects of environment, organism and task act as constraints determining the solution set available, and the coordination pattern is then implemented under a pressure for energetic economy. Environment is defined in terms of affordances based on the ecological psychology definition of the concept and organism is defined as classic morphology and physiology based capabilities. We rely on a novel conceptualization of task that recognizes that the task goal needs to be separated from the mechanisms that achieve the goal if the motivation behind the selection of the mechanism strategy is to be exposed and understood. This reformulation of the Sparrow and Newell construct is then linked to the proposed pressure for economy by considering it as an optimization problem, where the most readily selected gait strategy will be that which achieves the task goal at (or near) the energetic minimum. (shrink)

The dominant paradigm of experiments in the social and behavioral sciences views an experiment as a test of a theory, where the theory is assumed to generalize beyond the experiment's specific conditions. According to this view, which Alan Newell once characterized as “playing twenty questions with nature,” theory is advanced one experiment at a time, and the integration of disparate findings is assumed to happen via the scientific publishing process. In this article, we argue that the process of integration (...) is at best inefficient, and at worst it does not, in fact, occur. We further show that the challenge of integration cannot be adequately addressed by recently proposed reforms that focus on the reliability and replicability of individual findings, nor simply by conducting more or larger experiments. Rather, the problem arises from the imprecise nature of social and behavioral theories and, consequently, a lack of commensurability across experiments conducted under different conditions. Therefore, researchers must fundamentally rethink how they design experiments and how the experiments relate to theory. We specifically describe an alternative framework, integrative experiment design, which intrinsically promotes commensurability and continuous integration of knowledge. In this paradigm, researchers explicitly map the design space of possible experiments associated with a given research question, embracing many potentially relevant theories rather than focusing on just one. Researchers then iteratively generate theories and test them with experiments explicitly sampled from the design space, allowing results to be integrated across experiments. Given recent methodological and technological developments, we conclude that this approach is feasible and would generate more-reliable, more-cumulative empirical and theoretical knowledge than the current paradigm – and with far greater efficiency. (shrink)

In this interview, James L. McClelland responds to questions regarding connectionist models of cognition, a theory inspired by information processing in the brain. McClelland explains the distinction between symbolic and non-symbolic processing for a better understanding of mental processes. He argues that connectionist models can perform the computations which we know the brain can perform. In addition, he responds to several general questions on the perspectives of computational models of cognition.

Abstract:Disturbing cases continue to be published of patients declared brain dead who later were found to have a few intact brain functions. We address the reasons for the mismatch between the whole-brain criterion and brain death tests, and suggest solutions. Many of the cases result from diagnostic errors in brain death determination. Others probably result from a tiny amount of residual blood flow to the brain despite intracranial circulatory arrest. Strategies to lessen the mismatch include improving brain death determination training (...) for physicians, mandating a test showing complete intracranial circulatory arrest, or revising the whole-brain criterion. (shrink)

The publicity surrounding the recent McMath and Muñoz cases has rekindled public interest in brain death: the familiar term for human death determination by showing the irreversible cessation of clinical brain functions. The concept of brain death was developed decades ago to permit withdrawal of therapy in hopeless cases and to permit organ donation. It has become widely established medical practice, and laws permit it in all U.S. jurisdictions. Brain death has a biophilosophical justification as a standard for determining human (...) death but remains poorly understood by the public and by health professionals. The current controversies over brain death are largely restricted to the academy, but some practitioners express ambivalence over whether brain death is equivalent to human death. Brain death remains an accepted and sound concept, but more work is necessary to establish its biophilosophical justification and to educate health professionals and the public. (shrink)

Nair-Collins and Joffe (2023) highlighted the noncongruence between the language of the Uniform Determination of Death Act (UDDA) and the accepted brain death bedside testing standard by showing th...

The definition of death is one of the oldest and most enduring problems in biophilosophy and bioethics. Serious controversies over formally defining death began with the invention of the positive-pressure mechanical ventilator in the 1950s. For the first time, physicians could maintain ventilation and, hence, circulation on patients who had sustained what had been previously lethal brain damage. Prior to the development of mechanical ventilators, brain injuries severe enough to induce apnea quickly progressed to cardiac arrest from hypoxemia. Before the (...) 1950s, the loss of spontaneous breathing and heartbeat were perfect predictors of death because the functioning of the brain and of all other organs ceased rapidly and nearly simultaneously thereafter, producing a unitary death phenomenon. In the pretechnological era, physicians and philosophers did not have to consider whether a human being who had lost certain “vital functions” but had retained others was alive, because such cases were technically impossible. (shrink)

Among the old and new controversies over brain death, none is more fundamental than whether brain death is equivalent to the biological phenomenon of human death. Here, I defend this equivalency by offering a brief conceptual justification for this view of brain death, a subject that Andrew Huang and I recently analyzed elsewhere in greater detail. My defense of the concept of brain death has evolved since Bernard Gert, Charles Culver, and I first addressed it in 1981, a development that (...) paralleled advances in intensive care unit treatment. The century‐old concept of the organism as a whole provides the fundamental justification for the equivalency of brain death and human death. In our technological age, in which increasing numbers of components and systems of an organism can be kept alive, and for longer intervals, the permanent cessation of functioning of the organism as a whole is the phenomenon that best corresponds to its death. (shrink)

In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis—the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive activation (...) model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that contemporary versions of models based on the idea of interactive activation continue to provide a basis for efforts to achieve a fuller understanding of the process of perception. (shrink)

Scepticism about ought simpliciter is the view that there is no such thing as what one ought simpliciter to do. Instead, practical deliberation is governed by a plurality of normative standpoints, each authoritative from their own perspective but none authoritative simpliciter. This paper aims to resist such scepticism. After setting out the challenge in general terms, I argue that scepticism can be resisted by rejecting a key assumption in the sceptic’s argument. This is the assumption that standpoint-relative ought judgments bring (...) with them a commitment to act in accordance with those judgments. Instead, I propose an alternative account of our normative concepts according to which only ought simpliciter judgments commit one to acting in accordance with those judgments. In addition to answering the sceptical challenge, the proposal offers an independently motivated account of what makes a concept normatively authoritative. (shrink)

The locked-in syndrome is a state of profound paralysis with preserved awareness of self and environment who typically results from a brain stem stroke. Although patients in LIS have great difficulty communicating, their consciousness, cognition, and language usually remain intact. Medical decision-making by LIS patients is compromised, not by cognitive impairment, but by severe communication impairment. Former systems of communication that permitted LIS patients to make only “yes” or “no” responses to questions was sufficient to validate their consent for simple (...) medical decisions but not for consequential medical decisions such as whether to refuse further life-sustaining therapy. Emerging technologies including computer-tracking assistance of retained partial motor function and brain-computer interfaces promise to improve the communication ability of LIS patients and, when better developed, will allow them to fully exercise their right to actively participate in consequential medical decisions about their own medical care. Although so-called “covert cognition” patients clinically diagnosed as vegetative state that are shown to be aware by functional neuroimaging maybe metaphorically considered locked-in, it is nosologically more coherent not to categorize them formally as LIS. (shrink)

I consider the role of cognitive modeling in cognitive science. Modeling, and the computers that enable it, are central to the field, but the role of modeling is often misunderstood. Models are not intended to capture fully the processes they attempt to elucidate. Rather, they are explorations of ideas about the nature of cognitive processes. In these explorations, simplification is essential—through simplification, the implications of the central ideas become more transparent. This is not to say that simplification has no downsides; (...) it does, and these are discussed. I then consider several contemporary frameworks for cognitive modeling, stressing the idea that each framework is useful in its own particular ways. Increases in computer power (by a factor of about 4 million) since 1958 have enabled new modeling paradigms to emerge, but these also depend on new ways of thinking. Will new paradigms emerge again with the next 1,000‐fold increase? (shrink)

Despite the popularity, success, and growth of programs of organ donation after the circulatory determination of death (DCDD), a long‐standing controversy persists over whether the organ donor is truly dead at the moment physicians declare death, usually following five minutes of circulatory and respiratory arrest. Advocates of the prevailing death determination standard claim that the donor is dead when declared because of permanent cessation of respiration and circulation. Critics of this standard argue that while the cessation of respiration and circulation (...) may be permanent, it may not be irreversible at the moment death is declared because, if cardiopulmonary resuscitation were performed, it might succeed. And because irreversibility of cessation of respiration and circulation is required by both the statute and the biological concept of death, the donor must be alive. Who is correct?Making two related distinctions clarifies the cause of the disagreement over whether the DCDD donor is dead and points to a possible resolution. First, in a determination of death, there is an important distinction between the permanent and the irreversible cessation of circulation and respiration—two associated phenomena that are often confounded. Second, there is an important distinction between the medical practice standard for death determination, in which physicians certify the permanent cessation of vital functions as sufficient for death declaration, and the underlying biological concept of death that requires the irreversible cessation of vital functions because death, by definition, is an irreversible event. (shrink)

Organ donation after the circulatory determination of death requires the permanent cessation of circulation while organ donation after the brain determination of death requires the irreversible cessation of brain functions. The unified brain-based determination of death connects the brain and circulatory death criteria for circulatory death determination in organ donation as follows: permanent cessation of systemic circulation causes permanent cessation of brain circulation which causes permanent cessation of brain perfusion which causes permanent cessation of brain function. The relevant circulation that (...) must cease in circulatory death determination is that to the brain. Eliminating brain circulation from the donor ECMO organ perfusion circuit in thoracoabdominal NRP protocols satisfies the unified brain-based determination of death but only if the complete cessation of brain circulation can be proved. Despite its medical and physiologic rationale, the unified brain-based determination of death remains inconsistent with the Uniform Determination of Death Act. (shrink)

The concept of whole‐brain death is under attack again. Scholars are arguing that the concept of brain death per se—regardless of the focus on “higher,” “stem” or “whole”—is fundamentally flawed. These scholars have identified what they believe are serious discrepancies between the definition and criterion of brain death, and have pointed out that medical professionals and lay persons remain confused about its meaning. Yet whole‐brain death remains the standard for determining death in much of the Western world and its defenders (...) believe this concept best maps onto our everyday conception of death. (shrink)

“Brain death,” the determination of human death by showing the irreversible loss of all clinical functions of the brain, has become a worldwide practice. A biophilosophical account of brain death requires four sequential tasks: agreeing on the paradigm of death, a set of preconditions that frame the discussion; determining the definition of death by making explicit the consensual concept of death; determining the criterion of death that proves the definition has been fulfilled by being both necessary and sufficient for death; (...) and determining the tests of death for physicians to employ at the patient's bedside to demonstrate that the criterion of death has been fulfilled. The best definition of death is “the cessation of functioning of the organism as a whole.” The whole-brain criterion is the only criterion that is both necessary and sufficient for death. Brain death tests are used only in the unusual case in which a patient's ventilation is being supported. Brain death critics have identified weaknesses in its formulation. But despite its shortcomings, the whole-brain death formulation comprises a concept and public policy that make intuitive and practical sense and that has been well accepted by many societies. (shrink)

The distinction between the "permanent" (will not reverse) and "irreversible" (cannot reverse) cessation of functions is critical to understand the meaning of a determination of death using circulatory–respiratory tests. Physicians determining death test only for the permanent cessation of circulation and respiration because they know that irreversible cessation follows rapidly and inevitably once circulation no longer will restore itself spontaneously and will not be restored medically. Although most statutes of death stipulate irreversible cessation of circulatory and respiratory functions, the accepted (...) medical standard is their permanent cessation because permanence is a perfect surrogate indicator for irreversibility, and using it permits a more timely declaration. Therefore, patients properly declared dead in donation after circulatory death (DCD) protocols satisfy the requirements of death statutes and do not violate the dead donor rule. The acronym DCD should represent organ "donation after circulatory death" to clarify that the death standard is the permanent cessation of circulation, not heartbeat. Heart donation in DCD does not retroactively negate the donor's death determination because circulation has ceased permanently. (shrink)

Ariane Lewis provided an insightful review of several controversial cases of death by neurologic criteria (“brain death”) in the UK, focusing on Archie Battersbee, a boy whose tragic illness provok...

The overall purpose of this paper is to clarify the physical meaning and epistemological status of the term 'measurement' as used in quantum theory. After a review of the essential logical structure of quantum physics, Part I presents interpretive discussions contrasting the quantal concepts observable and ensemble with their classical ancestors along the lines of Margenau's latency theory. Against this background various popular ideas concerning the nature of quantum measurement are critically surveyed. The analysis reveals that, in addition to internal (...) mathematical difficulties, all the so-called quantum theories of measurement are grounded in unjustifiable, classical presuppositions. (shrink)

Metaethical expressivism is typically characterised as the view that normative statements express desire-like attitudes instead of beliefs. However, in this paper I argue that expressivists should claim that normative statements express beliefs in normative propositions, and not merely in some deflationary sense but in a theoretically robust sense explicated by a theory of propositional attitudes. I first argue that this can be achieved by combining an interpretationist understanding of belief with a nonfactualist view of normative belief content. This results in (...) a view I call ‘interpretative expressivism’. I then argue that traditional arguments employed by expressivists that normative statements express noncognitive attitudes can just as well support the claim that normative statements express nonfactual or nonrepresentational beliefs. Finally, I argue that this view has a number of advantages to versions of expressivism that deny that normative statements express non-deflationary normative beliefs. (shrink)

Thomas Hurka has recently proposed a utilitarian theory which would effect a compromise between Average and Total utilitarianism, the better to deal with issues in population ethics. This Compromise theory would incorporate the principle that the value which an extra happy person contributes to a possible world is a decreasing function of the total population of that world: that happy people are of diminishing marginal value. In spite of its initial plausibility I argue against this principle. I show that the (...) Compromise theory is actually no improvement over the two original versions of utilitarianism; in particular, it is subject to almost all the objections which are fatal to Average utilitarianism, and more besides. And I attempt to dispell the appearance that intuition supports the Compromise theory as against Total utilitarianism, by arguing that the latter's Repugnant Conclusion, when properly understood, is not intuitively unacceptable. Total utilitarianism remains a plausible ethical theory, while both the Average and the Compromise theories should be definitely rejected. (shrink)

A combination of emerging life support technologies and entrenched organ donation practices are complicating the physician's task of determining death. On the one hand, technologies that support or replace ventilation and circulation may render the diagnosis of death ambiguous. On the other, transplantation of vital organs requires timely and accurate declaration of death of the donor to keep the organs as healthy as possible. These two factors have led to disagreements among physicians and scholars on the precise moment of death. (...) In this article, I suggest that the debate about exactly when a person dies can benefit from distinguishing the strict biological concept of death from the medical standards for determining human death, and I show how an appreciation of the difference between the permanent and irreversible cessation of circulation is helpful in understanding the reasons for the two approaches to determining when death should be declared. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Rhetoric 35.2 (2002) 138-152 [Access article in PDF] Respecting the Rupture: Not Solving the Problem of Unity in Plato's Phaedrus James L. Kastely Plato's Phaedrus is a particularly instructive example of the double nature and status of rhetoric, for it embodies a tension at the heart of rhetoric. The first half of the dialogue presents three examples of rhetorical practice, while the second develops a theoretical (...) justification of rhetoric as an art. Thus, the dialogue would seem to offer a productive negotiation of the practice/theory tension. What makes the dialogue interesting, however, is the fact that this negotiation does not occur. The dialogue does not bring theory and practice into a harmonious relation, for there is a troubling discontinuity between its two halves, and rhetorical practice feels fractured. The exploration of eros that had occupied the first half of the dialogue is abandoned before the beginning of the second half, and then, following a logic that is at best associational, Socrates and Phaedrus explore the standards that should govern the practice of rhetoric. The infelicity of this transition raises a question: why did Plato structure the Phaedrus in such a way that it emphasized the dissonance between the two halves of the dialogue? To pose the question this way, however, is to go in a direction different from many of the best contemporary interpretations of the dialogue, which either argue that the dialogue is unified (Griswold 164) or suggest that the dissonance between its two halves reflects a shift in Plato's approach to philosophy (Kahn 373; Nehamas 352). In contrast, I will argue that the rupture in the dialogue is thematically purposive, for it points to an inescapable schism within rhetoric that makes rhetoric philosophically interesting.Socrates' second speech, his palinode to Eros, is a rhetorical tour de force that closes the first half of the dialogue. The importance of the palinode, however, is not limited to its role as an exemplary rhetorical performance, [End Page 138] for it also plays a crucial role in resolving the problem of erotic madness that organizes the intellectual drama of the first half. It would seem reasonable to expect that such an important and powerful moment in the dialogue would, at the very least, play a significant role in the philosophical discussion that composes the dialogue's second half. But that doesn't happen. While Socrates does refer to the palinode in his theoretical discussion of rhetoric, he makes little use of it, and, more important, he is silent on the subject of eros. Both the dramatic organization of the second half of the dialogue and its theoretical discussion cooperate to turn the rhetorical triumph of the palinode into a problem. Why has eros been abandoned as a philosophic topic, and what does this abandoning imply about the erotically grounded rhetoric that Socrates practiced and defended?To make matters worse, Socrates himself dismisses the palinode as a serious effort. He characterizes the speech as little more than a pleasant game, one that is not without value only because "these two certain forms (of gathering and dividing) were stated by chance" (265c). Far from viewing the palinode as possessing philosophical significance, Socrates appears to value it principally for its being a so-so example of a work of rhetoric that has been shaped by dialectic. While it is hard not to take Socrates' dismissal of the seriousness of the speech as partially disingenuous (just prior to his dismissal, he refers to the palinode as serious and reverent [265b]), he also does seem to mean what he says. Whether he is being straightforward or ironic does not finally matter because in either case the problem that occupies him and Phaedrus in the first half has disappeared from the dialogue. And that creates a problem: for if the philosophic issues of the first half of the dialogue drop out, then the dialogue is not coherent.This incoherence is especially troubling given Socrates' explicit endorsement of coherence as an important rhetorical value. In fact, when he begins his... (shrink)

The study of human intelligence was once dominated by symbolic approaches, but over the last 30 years an alternative approach has arisen. Symbols and processes that operate on them are often seen today as approximate characterizations of the emergent consequences of sub- or nonsymbolic processes, and a wide range of constructs in cognitive science can be understood as emergents. These include representational constructs (units, structures, rules), architectural constructs (central executive, declarative memory), and developmental processes and outcomes (stages, sensitive periods, neurocognitive (...) modules, developmental disorders). The greatest achievements of human cognition may be largely emergent phenomena. It remains a challenge for the future to learn more about how these greatest achievements arise and to emulate them in artificial systems. (shrink)

This paper examines the general prospects for conceptual role expressivism, expressivist theories that embrace conceptual role semantics. It has two main aims. The first aim is to provide a general characterisation of the view. The second aim is to raise a challenge for the general view. The challenge is to explain why normative concepts are not a species of defective concepts, where defective concepts are those that cannot meaningfully embed and participate in genuine inference. After rejecting existing attempts to answer (...) the challenge, I propose an alternative solution. However, the solution leaves conceptual role expressivism a far less distinctive and interesting position than its proponents claim. I conclude that we should be sceptical about how much expressivists gain by appealing to conceptual role semantics. (shrink)

Notwithstanding these wise pronouncements, my project here is to characterize the biological phenomenon of death of the higher animal species, such as vertebrates. My claim is that the formulation of “whole- brain death ” provides the most congruent map for our correct understanding of the concept of death. This essay builds upon the foundation my colleagues and I have laid since 1981 to characterize the concept of death and refine when this event occurs. Although our society's well-accepted program of multiple (...) organ procurement for transplantation requires the organ donor first to be dead, the concept of brain death is not merely a social contrivance to permit us to obtain the benefits of organ procurement. Rather, the concept of whole- brain death stands independently as the most accurate biological representation of the demise of the human organism. (shrink)

'The interpretours of Plato,' wrote Sir Thomas Elyot in The Governour, 'do think that the wonderful and incomprehensible order of the celestial bodies, I mean sterres and planettes, and their motions harmonicall, gave to them that intensifly and by the deepe serche of raison beholde their coursis, in the sondrye diversities of number and tyme, a forme of imitation of a semblable motion, which they called daunsigne or sltation.' The image of the planets and stars engaged in an ordered and (...) measured dance is an ancient one. Plato articulated it in a passage in the Timaeus, where he likened the apparent motions of the planets and stars to 'choreiai'. Through the centuries the analogy has challenged Plator's interpreters to define and elaborate the image. Miller has examined a range of poetic and philosophical texts influenced by Plato cosmology, and has discovered frequent comparisons of the cosmic order to 'daunsigne.' He suggests that the vision of the cosmic dance did not develop at random in Western intellectual history but originated in a specific philosophical context and passed through stages of evolution that reflect Gnostic, Christian, Stoic, and Neoplatonic responses to Plato. He argues that the historical variations of the image were often closely related to adaption or criticisms of Plato's theories of visual perception and intellectual vision. The dance, in conjunction with images such as the Great chain of Being and the Lyre of the Heavens, became the dominant image of a peculiarly Late Antique world-view which Miller has called the 'poetic universe'; a world where metaphors, metonymies, and personifications could exist in fact as well as in word. The result of Miller's analysis is vast in scope. The nine chapters of the book each present a thesis on a particular author, but all function together like links in a chain. Miller has been described as 'an historian of visions'; the book has been likened to Auerbach's Mimesis. It is a remarkable contribution to an understanding of the complex interaction of ideas and images in time. (shrink)

Expressivists about normative thought and discourse traditionally deny that there are nondeflationary normative propositions. However, it has recently been suggested that expressivists might avoid a number of problems by providing a theory of normative propositions compatible with expressivism. This paper explores the prospects for developing an expressivist theory of propositions within the framework of cognitive act theories of propositions. First, I argue that the only extant expressivist theory of cognitive propositions—Michael Ridge's ‘ecumenical expressivist’ theory—fails to explain identity conditions for normative (...) propositions. Second, I argue that this failure motivates a general constraint—the ‘unity requirement’—that any expressivist theory of propositions must provide a unified nonrepresentational explanation of that in virtue of which propositional attitudes have the content that they have. Third, I argue that conceptual role accounts of content provide a promising framework in which to develop an expressivist theory of cognitive propositions. (shrink)