Ken Aizawa

It is sometimes suggested that the history of computation in cognitive science is one in which the formal apparatus of Turing-equivalent computation, or effective computability, was exported from mathematical logic to ever wider areas of cognitive science and its environs. This paper, however, indicates some respects in which this suggestion is inaccurate. Computability theory has not been focused exclusively on Turing-equivalent computation. Many essential features of Turing-equivalent computation are not captured in definitions of computation as symbol manipulation. Turing-equivalent computation did not play the role in McCulloch and Pitts’s early cybernetic work that is sometimes attributed to it. Finally, various segments of the neuroscientific community invoke a notion of computation that differs from the Turing-equivalent notion.Keywords: Circular causality; Computation; Cortical maps; Neural networks; Symbol manipulation; Turing-equivalent computation.

Explanations of psychological regularities in terms of biological regularities are undoubtedly appealing for many reasons. In addition, the scientific methodology that searches for such explanations certainly has merit. Nonetheless, the history of neuroscience, psychology, and computer science over the last one hundred years, indicates that such explanations are difficult to find and that the methodology of searching for them often frustrating. Recent attempts to provide "neurally-inspired" explanations of psychological regularities embodied in the theory of parallel distributed processing, PDP, also show signs of these difficulties. The more neurobiologically accurate portions of PDP are isolated from the more psychologically plausible portions, while the portions dedicated to computational analyses of neural networks tend to be isolated from both biology and psychology. Since, however, we may be sure that some day there will be some true scientific and philosophic theory of the role of neurons in mentation, we may press on in the enterprise, using what we have now as a point of departure. In this spirit, we may consider evolutionary explanations of features of our neural hardware. By pursuing evolutionary explanations via computer simulations, genetic algorithms, we have a new direction in which to proceed in our neural network theorizing. A second project we pursue is the application of a neural network studied in PDP computer science, the Boltzmann machine, to psychological phenomena. Here the psychological phenomena are those found in human decision making under risk and captured in Kahneman and Tversky's prospect theory.

In two recent books, Jerry Fodor has developed a set of sufficient conditions for an object “X” to non-naturally and non-derivatively mean X. In an earlier paper we presented three reasons for thinking Fodor's theory to be inadequate. One of these problems we have dubbed the “Pathologies Problem”. In response to queries concerning the relationship between the Pathologies Problem and what Fodor calls “Block's Problem”, we argue that, while Block's Problem does not threatenFodor's view, the Pathologies Problem does.

Introduction to the 2009 Synthese Special Issue on Philosophy and Neuroscience. The papers are: The multiplicity of experimental protocols: a challenge to reductionist and non-reductionist models of the unity of neuroscience Jacqueline A. Sullivan Making sense of mirror neurons Lawrence Shapiro Evaluating the evidence for multiple realization Thomas W. Polger Multiple realization and methodological pluralism Robert C. Richardson Neuroscience and multiple realization: a reply to Bechtel and Mundale Ken Aizawa.

An important question in the debate over embodied, enactive, and extended cognition has been what has been meant by “cognition”. What is this cognition that is supposed to be embodied, enactive, or extended? Rather than undertake a frontal assault on this question, however, this paper will take a different approach. In particular, we may ask how cognition is supposed to be related to behavior. First, we could ask whether cognition is supposed to be behavior. Second, we could ask whether we should attempt to understand cognitive processes in terms of antecedently understood cognitive behaviors. This paper will survey some of the answers that have been given in the embodied, enactive, and extended cognition literature, then suggest reasons to believe that we should answer both questions in the negative.

Many years after the publication of “A Logical Calculus of the Ideas Immanent in Nervous Activity,” Warren McCulloch gave Walter Pitts credit for contributing his knowledge of modular mathematics to their joint project. In 1941 I presented my notions on the flow of information through ranks of neurons to Rashevsky’s seminar in the Committee on Mathematical Biology of the University of Chicago and met Walter Pitts, who then was about seventeen years old. He was working on a mathematical theory of learning and I was much impressed. He was interested in problems of circularity, how to handle regenerative nervous activity in closed loops....For two years Walter and I worked on these problems whose solution depended upon modular mathematics of which I knew nothing, but Walter did.. In this paper, we will fill in some of the details regarding Pitts’s interest in problems of circularity, regenerative activity in closed loops of neurons, and modular mathematics, and the way in which they relate to “A Logical Calculus.”

Philosophical interest in situated cognition has been focused most intensely on the claim that human cognitive processes extend from the brain into the tools humans use. As we see it, this radical hypothesis is sustained by two kinds of mistakes, confusing coupling relations with constitutive relations and an inattention to the mark of the cognitive. Here we wish to draw attention to these mistakes and show just how pervasive they are. That is, for all that the radical philosophers have said, the mind is still in the head.

There has recently been controversy over the existence of 'multiple realization' in addition to some confusion between different conceptions of its nature. To resolve these problems, we focus on concrete examples from the sciences to provide precise accounts of the scientific concepts of 'realization' and 'multiple realization' that have played key roles in recent debates in the philosophy of science and philosophy of psychology. We illustrate the advantages of our view over a prominent rival account ( Shapiro, 2000 and 2004 ) and use our work to rebut recent objections to the long-standing claim that psychological properties are multiply realized. For we use scientific evidence, in combination with our more precise theoretical framework, to show that we have strong reason to believe that psychological properties are indeed multiply realized both at the biochemical and neuronal levels.

Terry Horgan and John Tienson have suggested that connectionism might provide a framework within which to articulate a theory of cognition according to which there are mental representations without rules (RWR) (Horgan and Tienson 1988, 1989, 1991, 1992). In essence, RWR states that cognition involves representations in a language of thought, but that these representations are not manipulated by the sort of rules that have traditionally been posited. In the development of RWR, Horgan and Tienson attempt to forestall a particular line of criticism, theSyntactic Argument, which would show RWR to be inconsistent with connectionism. In essence, the argument claims that the node-level rules of connectionist networks, along with the semantic interpretations assigned to patterns of activation, serve to determine a set of representation-level rules incompatible with the RWR conception of cognition. The present paper argues that the Syntactic Argument can be made to show that RWR is inconsistent with connectionism.

In ‘‘The Myth of Original Intentionality,’’ Daniel Dennett appears to want to argue for four claims involving the familiar distinction between original (or underived) and derived intentionality. 1. Humans lack original intentionality. 2. Humans have derived intentionality only. 3. There is no distinction between original and derived intentionality. 4. There is no such thing as original intentionality. We argue that Dennett’s discussion fails to secure any of these conclusions for the contents of thoughts.

In his recent critical notice of The Bounds of Cognition in this journal, Justin Fisher advances a set of concerns that favor the hypothesis that, under certain circumstances, cognitive processes span the brain, body, and world. One is that it is too much to require that representations in cognitive process must have non-derived content. A second is that it is possible that extended objects bear non-derived content. A third is that extended cognition might advocate the extension of certain general categories of cognition. A fourth is that Bounds misapplies Andy Clark and David Chalmers’ so-called “parity principle.” The purpose of this rejoinder is to show how Fisher’s concerns can be, or have already been, addressed.

This is a plausible reading of what Clark and Chalmers had in mind at the time, but it is not the radical claim at stake in the extended cognition debate.[1] It is a familiar functionalist view of cognition and the mind that it can be realized in a wide range of distinct material bases. Thus, for many species of functionalism about cognition and the mind, it follows that they can be realized in extracranial substrates.[2] And, in truth, even some non-functionalist views of cognition apparently allow for the possibility that cognition extends into the external world.[3] So, the (logical, conceptual, or nomological) possibility of extended cognition seems to us not the kind of radical view the advocates of this view have often implied. This is not, of course, to assess or pass judgment on the truth of these possibilities; it is only to note that they are not what most agitates people about the hypothesis of extended cognition. Framing the radical extended cognition hypothesis is a more delicate matter than framing the modal extended cognition hypothesis, but something like the following is in the ballpark. The radical extended cognition hypothesis maintains that, in many mundane cases of tool use, human cognitive processes extend into the tools. The principal reason this hypothesis is so delicate is that there remains much room for dispute about what constitutes a.

One way that scientifically recognized properties are multiply realized is by “compensatory differences” among realizing properties. If a property G is jointly realized by two properties F1 and F2, then G can be multiply realized by having changes in the property F1 offset changes in the property F2. In some cases, there are scientific laws that articulate how distinct combinations of physical quantities can determine one and the same value of some other physical quantity. One moral to draw is that in such cases we have the multiple realization of a single determinate, “fine grained” property instance that is exactly similar to another instance. As simple as this moral is, it has ramifications for a number of recent discussions of multiple realization in science. Taken collectively, these ramifications indicate that multiple realization by compensatory adjustments merits greater attention in the philosophy of science literature than it has hitherto received.

Despite the considerable attention that the systematicity argument has enjoyed, it is worthwhile examining the argument within the context of similar explanatory arguments from the history of science. This kind of analysis helps show that Connectionism, qua Connectionism, really does not have an explanation of systematicity. Second, and more surprisingly, one finds that the systematicity argument sets such a high explanatory standard that not even Classicism can explain the systematicity of thought.

Philosophical interest in situated cognition has been focused most intensely on the claim that human cognitive processes extend from the brain into the tools humans use. As we see it, this radical hypothesis is sustained by two kinds of mistakes, the confusion of coupling relations with constitutive relations and an inattention to the mark of the cognitive. Here we wish to draw attention to these mistakes and show just how pervasive they are. That is, for all that the radical philosophers have said, the mind is still in the head.

Despite the prominence of the systematicity argument in the debate between Classicists and Connectionists, there is extremely widespread misunderstanding of the nature of the argument. For example, Matthews (1994), has argued that the systematicity argument is a kind of trick, where Niklasson and van Gelder (1994), have claimed that it is obscure. More surprisingly, once one examines the argument carefully, one finds that Fodor, Pylyshyn, and McLaughlin, themselves have not fully understood it. 1 In part as a result of this, many Connectionists who have tried to meet the challenge of explaining the systematicity of thought have been misled about what this challenge involves (e.g. Pollack 1990; Smolensky 1990; Niklasson and van Gelder 1994). I have five principal objectives in this paper. First, I want to respond to those who believe that the systematicity argument is mere obscurity by providing a clear presentation of it. Second, and at the same time, I want to respond to those who believe the argument is mere trickery by showing it to be an instance of a rather familiar form of legitimate scientific reasoning. Third, having seen what sort of reasoning is involved in the argument, I wish to indicate how certain attempts to meet the challenge of systematicity are inadequate. Fourth, having seen the explanatory standard set by the systematicity argument, I want to indicate how even Fodor, Pylyshyn, and McLaughlin, fail to see how Classicism fails to meet the standard. Fifth, and finally, I wish to indicate what consequences the foregoing considerations have for the prospects of Classicism and Connectionism.