Research in computational cognitive modeling investigates the nature of cognition through developing process-based understanding by specifying computational models of mechanisms (including representations) and processes. In this enterprise, a cognitive architecture is a domaingeneric computational cognitive model that may be used for a broad, multiple-level, multipledomain analysis of behavior. It embodies generic descriptions of cognition in computer algorithms and programs. Developing cognitive architectures is a difficult but important task. In this article, discussions of issues and challenges in developing cognitive architectures will (...) be undertaken, and an example cognitive architecture (CLARION) will be described. (shrink)

The thesis is intended to contribute to the growing understanding of the indispensable role played by phenomenal consciousness in human cognition, and specifically in making our concepts of the external world available. The focus falls on so called observational concepts, a type of rudimentary, perceptually-based objective concepts in our repertoire — picking out manifest properties such as colors and shapes. A theory of such concepts gets provided, and, consequently, the exact role that perceptual consciousness plays in making concepts of this (...) sort available gets settled. In the first half of the thesis, observational concepts get construed as a special type of recognitional concepts. On an analogy with perceptual demonstratives, having such concepts would involve having non-trivial knowledge of their reference. The experiential basis of such concepts would, among other things, provide for such constitutive knowledge. The theoretical background relevant to the hypothesis gets provided in the first chapter. A defence of the hypothesis follows in the second. In the second half of the thesis, care is taken to distinguish among two ways in which the constitutive knowledge of the reference of an observational concept could be fleshed out. In the third chapter, perceptual experience is shown to provide the basis both for knowledge of observational properties by acquaintance, and for knowledge of the essence of such properties — provided that knowledge of essence gets construed in the right, modest way. It might be natural to take knowledge by acquaintance to be the sort relevant to observational concept possession, especially given that in the case of perceptual demonstratives this is the role likely played by experience. However, this initial impression proves to be mistaken. The constitutive knowledge of the referent of an observational concept turns out to consist in the capacity to determine a priori the essence of the respective property. To show this, an argument gets provided in the penultimate fourth chapter, based on the key role played by experiences of instances of observational properties in optimal viewing conditions in enabling the possession of the respective observational concept. (shrink)

I believe that there are only a select few topics, which arouse a similar level of interest and curiosity among academics and laymen alike, as does the study of mind and brain. Although mind and brain have been capturing the attention of philosophers for centuries, it is the "scientific investigation" of age old philosophical queries by socalled cognitive scientists, which is distinctive of the developments of the last few decades and which, in times to come, may well be considered the (...) hallmark of the study of mind in the 20th and early 21st centuries. In the past, advances in the natural sciences underlay or boosted a plethora of developments in the technological, economic and political spheres that not only improved the standard of living and prolonged the average life span for a vast number of people, but also fuelled hopes that a new and improved understanding of the nature of man was also within reach. Despite all the benefits mankind derived from scientific and technological progress past and present, the success of the natural sciences also helped spread and foster a virulent and nowadays quasi-ubiquitous and unquestioned believe in the omnipotence of science and technology. In the context of the study of mind, in particular, it fostered the widespread conception that in order for an investigation leading to insight and understanding a "scientific" approach is a sine qua non. This thesis highlights the danger of such an approach. By investigating the framework of explanation adopted by cognitive scientists, the cognitive view, and by examining its inherent conceptions of mind and thought, it will be shown that the scientific, or rather scientistic, approach inherent in the views depicted above is highly questionable, and in the case of the study of mind and brain, does not further insight and understanding, but rather prevents it. In the 20th century, Ludwig Wittgenstein has been one of the few philosophers who recognized the fallaciousness of these ideas and who opposed the inherent scientism. His later philosophy, which provides the philosophical mise en scène for the following investigations, provides a much-needed antidote against the misconceptions common among cognitive scientists today. Although, many of the shortcomings of the ideas and views of cognitive scientists have, with a certain regularity, been discussed by philosophers working in the tradition of the later Wittgenstein their criticisms, more often than not, fell on deaf ears. I believe that one of the main reasons underlying the imperviousness of the community of cognitive scientists to the criticism of the kind of analytic philosophy inspired by the later Wittgenstein, is that it mainly focused on select misconceptions inherent in the cognitive view, but regularly failed to point out their place in the overall framework of thought for cognitive scientists. As a result, it was easy to dismiss these criticisms with excuses of the sort "but that does not bear any direct relevance to the work I do...". For this reason, this thesis aimed to portray and examine the cognitive view in its entirety, i.e. to depict the intricate interconnections existing between the premises that provide the foundation of the cognitive view, and to point out their disastrous consequences for our understanding not only of a select view aspects of mental phenomena, but to our understanding of the mind in its entirety. In order to provide such a "big picture", and to describe the numerous often very subtle interconnections between the various ideas making up the cognitive view in all their breadth and depth, a lot of well-trodden ground had to be revisited and reviewed. Thus, Anthony Kenny's and Peter Hackers' discussions of the mereological fallacy will provide the "base camp" from which we will visit less familiar aspects of the cognitive view via novel routes on our way to the peak of this "philosophical mountain". Where required, my indebtedness to the works of these philosophers will be highlighted throughout the text. (shrink)

Imagine, if you will, that the entire community of investigators interested in the problems of perception all lived together in the same town. Some continual shuffling of neighbors would be inevitable, and there might be occasional episodes of mass relocation and energetic bulldozing, but after a while the residents would probably settle down and find themselves living in districts defined roughly by disciplinary boundaries. The experimental psychologists would occupy the newer part of town, laced with superhighways, workshops and factories, machines (...) and measuring instruments, computers and overhead display units. But the town also has an Old City, marked by the complete absence of highways and factories, where the streets are lined with ancient hovels. There are, to be sure, some colossal palaces and museums in this part of town, breathtaking monuments to the grandeur of past centuries, but the current residents lack the inclination to construct such buildings, and many of the old palaces have been boarded up and condemned as unfit for human habitation. The somewhat scraggly and irascible inhabitants of this district have few viable economic enterprises, and no free markets, but rather organize themselves in units resembling nothing so much as medieval guilds. Congratulations. You have stumbled into the neighborhood where the philosophers live. (shrink)

Recent work in experimental psychology and neuroscience has revealed a rather surprising architecture for early (or preattentive) perceptual processes. This paper will describe some of the surprising features of that architecture, and how they bear on recent philosophical debates about the notion of phenomenal consciousness. I will argue that the common sense idea that states of phenomenal consciousness are states of a unitary kind cannot survive confrontation with the details of how our early perceptual processing works. In particular, that architecture (...) forces us to contemplate the prospect of phenomenal consciousness being sundered in two, with states that have phenomenal character making an appearance far before the arrival of anything one could call consciousness or awareness. (shrink)

A key element of the distinction between explicit and implicit cognitive functioning is the presence or absence of conscious awareness. In this review, we consider the proposal that neuropsychological disorders can best be considered in terms of a decoupling between preserved implicit or unconscious processing and impaired explicit or conscious processing. Evidence for dissociations between implicit and explicit processes in blindsight, amnesia, object agnosia, prosopagnosia, hemi-neglect, and aphasia is examined. The implications of these findings for a) our understanding of a (...) variety of neuropsychological disorders, b) the conceptualization of normal cognitive functioning, c) the neural basis of consciousness, and d) the clinical rehabilitation of brain-injured individuals are also discussed. (shrink)

In this paper I shall defend a projectivist view of sensory experience. The case I shall focus on is that of color experience. Projectivism has recently been criticized by some authors who claim that it is unintelligible, or at least implausible, and that it makes a severe category mistake. I shall argue that despite some prima facie impressions of implausibility, projectivism can be made intelligible, and plausible, if its details are spelled out in a reasonable way. In addition, projectivism is (...) ubiquitous in human psychology, and certain cases of projection are reasonably viewed as making a category mistake. Viewed from this perspective, sensory projection is just one instance of projectivism, brought about by low-level perceptual processing. Whether sensory projection is one that makes a category mistake is not obvious. However, even if it does, this is perfectly compatible with the evolutionary advantage of sensation and perception. (shrink)

Chomsky’s (1995, 2000a) Minimalist Program (MP) invites a perspective on semantics that is distinctive and attractive. In section one, I discuss a general idea that many theorists should find congenial: the spoken or signed languages that human children naturally acquire and use— henceforth, human languages—are biologically implemented procedures that generate expressions, whose meanings are recursively combinable instructions to build concepts that reflect a minimal interface between the Human Faculty of Language (HFL) and other cognitive systems. In sections two and three, (...) I develop this picture in the spirit of MP, in part by asking how much of the standard Frege-Tarski apparatus is needed in order to provide adequate and illuminating descriptions of the “concept assembly instructions” that human languages can generate. I’ll suggest that we can make do with relatively little, by treating all phrasal meanings as instructions to assemble number-neutral concepts that are monadic and conjunctive. But the goal is not to legislate what counts as minimal in semantics. Rather, by pursuing one line of Minimalist thought, I hope to show how such thinking can be fruitful. (shrink)

This dissertation proposes the central elements of a Social Enactive Theory of Perception. According to SEP, perception consists in sensory-based practices of interaction with objects, events, and states of affairs that are socially constituted. I oppose the representational view that perception is an indirect contact with the world, consists of the passive receiving and processing of sensory input, is in need of constant assessment of accuracy, and is a matter of individuals alone. I share the basic enactivist insight that perception (...) is a type of activity, but I depart from standard enactivism on the grounds of its individualistic bias and its limited conception of activity. Instead of motor actions, I formulate the concept of perceptual practices as the appropriate framework to understand perception. Perception is woven into socially informed, contextual, sensory-based everyday activities, such as food, dance, and dress, and even seemingly independent, basic perceptual activities and concepts are constituted by such practices. Perceptual individual interactions instantiate social perceptual practices but are not just repetitions of a script. We perceive objects in virtue of perspectives or appearances, not in spite of them, and on this basis I offer SEPâs take on experience, properties, and contents. I conceive perceptual experience as finely grained interactions between subjects and objects, both of which are spatially, temporally, and pragmatically situated. Objects and their sensory properties are perceived dynamically and always in multiple appearances. Perceptual content offers a pragmatic specification of the perceptual objects in the specific ways they appear to subjects. For SEP, perception is normatively structured. SEPâs perceptual normativity is not a worry about a supposed constant threat that our perceptions be nonveridical, but about the placement of perceptual things in a system of possibilities and expectations, cast in terms of degrees of fulfillment of expectations and in a horizon of pragmatic significance, both of which are functions of the socially constituted interactions between a perceiver and a rich theory of appearances. (shrink)

Is consciousness independent of the general-purpose information processes known as ‘cognitive access’? The dominantmethodology for supporting this independence hypothesis appeals to partial report experiments as evidence for perceptual consciousness in the absence of cognitive access. Using a standard model of evidential support, and reviewing recent elaborations of the partial report paradigm, this article argues that the paradigm has the wrong structure to support the independence hypothesis. Like reports in general, a subject’s partial report is evidence that she is conscious of (...) information only where that information is cognitively accessed. So partial report experiments could dissociate consciousness from cognitive access only if there were uncontroversial evidence forconsciousness which did not imply reportability. There is no such evidence. An alternative, broadly Marrian methodology for supporting the independence hypothesis is suggested, and some challenges to it outlined. This methodology does not require experimental evidence for consciousness in the absence of cognitive access. Instead it focuses on a function of perceptual consciousness when a stimulus is cognitively accessed. If the processes best suited to implement this function exclude cognitive access, the independence hypothesis will be supported. One relevant function of consciousness may be reflected in reason-based psychological explanations of a subject’s behaviour. (shrink)

As far as an adequate understanding of phenomenal consciousness is concerned, representationalist theories of mind which are modelled on the information processing paradigm, are, as much as corresponding neurobiological or functionalist theories, confronted with a series of arguments based on inverted or absent qualia considerations. These considerations display the following pattern: assuming we had complete knowledge about the neural and functional states which subserve the occurrence of phenomenal consciousness, would it not still be conceivable that these neural states (or states (...) with the same causal r. (shrink)

We examine a number of investigations of perceptual economy or, more specifically, of minimum tendencies and minimum principles in the visual perception of form, depth, and motion. A minimum tendency is a psychophysical finding that perception tends toward simplicity, as measured in accordance with a specified metric. A minimum principle is a theoretical construct imputed to the visual system to explain minimum tendencies. After examining a number of studies of perceptual economy, we embark on a systematic analysis of this notion. (...) We examine the notion that simple perceptual representations must be defined within the "geometric constraints" provided by proximal stimulation. We then take up metrics of simplicity. Any study of perceptual economy must use a metric of simplicity; the choice of metric may be seen as a matter of convention, or it may have deep theoretical and empirical implications. We evaluate several answers to the question of why the visual system might favor economical representations. Finally, we examine several accounts of the process for achieving perceptual economy, concluding that those which favor massively parallel processing are the most plausible. (shrink)