Human agents draw a variety of inferences effortlessly, spontaneously, and with remarkable efficiency – as though these inferences were a reflexive response of their cognitive apparatus. Furthermore, these inferences are drawn with reference to a large body of background knowledge. This remarkable human ability seems paradoxical given the complexity of reasoning reported by researchers in artificial intelligence. It also poses a challenge for cognitive science and computational neuroscience: How can a system of simple and slow neuronlike elements represent a large (...) body of systemic knowledge and perform a range of inferences with such speed? We describe a computational model that takes a step toward addressing the cognitive science challenge and resolving the artificial intelligence paradox. We show how a connectionist network can encode millions of facts and rules involving n-ary predicates and variables and perform a class of inferences in a few hundred milliseconds. Efficient reasoning requires the rapid representation and propagation of dynamic bindings. Our model (which we refer to as SHRUTI) achieves this by representing (1) dynamic bindings as the synchronous firing of appropriate nodes, (2) rules as interconnection patterns that direct the propagation of rhythmic activity, and (3) long-term facts as temporal pattern-matching subnetworks. The model is consistent with recent neurophysiological evidence that synchronous activity occurs in the brain and may play a representational role in neural information processing. The model also makes specific psychologically significant predictions about the nature of reflexive reasoning. It identifies constraints on the form of rules that may participate in such reasoning and relates the capacity of the working memory underlying reflexive reasoning to biological parameters such as the lowest frequency at which nodes can sustain synchronous oscillations and the coarseness of synchronization. (shrink)

‘The Natural System’ is the abstract notion of the order in living diversity. The richness and complexity of this notion is revealed by the diversity of representations of the Natural System drawn by ornithologists in the Nineteenth Century. These representations varied in overall form from stars, to circles, to maps, to evolutionary trees and cross-sections through trees. They differed in their depiction of affinity, analogy, continuity, directionality, symmetry, reticulation and branching, evolution, and morphological convergence and divergence. Some representations were two-dimensional, (...) and some were three-dimensional; n-dimensional representations were discussed but never illustrated. The study of diagrammatic representations of the Natural System is made difficult by the frequent failure of authors to discuss them in their texts, and by the consequent problem of distinguishing features which carried meaning from arbitrary features and printing conventions which did not. Many of the systematics controversies of the last thirty years have their roots in the conceptual problems which surrounded the Natural System in the late 1800s, problems which were left unresolved when interest in higher-level systematics declined at the turn of this century. (shrink)

Accounts of the evolutionary past have as much in common with works of narrative history as they do with works of science. Awareness of the narrative character of evolutionary writing leads to the discovery of a host of fascinating and hitherto unrecognized problems in the representation of evolutionary history, problems associated with the writing of narrative. These problems include selective attention, narrative perspective, foregrounding and backgrounding, differential resolution, and the establishment of a canon of important events. The narrative aspects of (...) evolutionary writing, however, which promote linearity and cohesiveness in conventional stories, conflict with the underlying chronicle of evolution, which is not linear, but branched, and which does not cohere, but diverges. The impulse to narrate is so great, however, and is so strongly reinforced by traditional schemes of taxonomic attention, that natural historians have more often abandoned the diverging tree than they have abandoned the narrative mode of representation. If we are to understand the true nature of the evolutionary past then we must adopt “tree thinking”, and develop new and creative ways, both narrative and non-narrative, of telling the history of life. (shrink)

The target article proposes a model involving the important but not well-investigated topics of curiosity and creativity. The model, however, falls short of providing convincing explanations of the basic mechanisms underlying these phenomena. We outline the importance of mechanistic thinking in dealing with the concepts outlined in this article specifically and within psychology and cognitive neuroscience in general.

Cognitive architectures, like programming languages, make commitments only at the implementation level and have limited explanatory power. Their universality implies that it is hard, if not impossible, to justify them in detail from finite quantities of data. It is more fruitful to focus on particular tasks such as language understanding and propose testable theories at the computational and algorithmic levels.

Festschrift in honor of Damodhar Mahapatra Shastri, 1890-1975, Sanskritist; comprises research articles on Vedic literature, religion, and Sanskrit grammar.

Chakravarthi Ram-Prasad offers illuminating new perspectives on contemporary phenomenological theories of body and subjectivity, based on studies of diverse classical Indian texts. He argues for a 'phenomenological ecology' of bodily subjectivity in health, gender, contemplation, and lovemaking.

Vedānta endeavours to base itself essentially on the facts of experience—in the fullest sense of the term. It recognizes the occurrence of everyday experience and the so-called fact of evil, but it refuses to view them as real. The real, it says, like Hegel, does not exist, and that which exists is not real. Evil is only an “existent"—as all this Samsara is—but not the ultimate Real. But it will be at once objected that if evil is an appearance, a (...) Maya, why should this appearance appear at all? If it has no foundation in reality, how and why does it occur at all? Further, how can anything be known as real unless it should appear ? Reality must appear. (shrink)

Contrary to the assertions made in the target article, temporal synchrony, coupled with an appropriate choice of representational primitives, leads to a functionally adequate and neurally plausible architecture that addresses the massiveness of the binding problem, the problem of 2, the problem of variables, and the transformation of activity-based transient representations of events and situations into structure-based persistent encodings of the same.

Lithium, despite its simple structure, has numerous biological effects. It also has a remarkable therapeutic effect in the prophylactic treatment of manic depression, and is finding a role in controlling aggressive and self‐mutilating behavior. The special feature of lithium is that it only acts on overactive systems to bring them back to normal, without affecting the stable system. The mechanisms of action of this simple cation are still largely unknown although the inositol depletion theory is the most widely accepted model. (...) A recent paper(1) described a different molecular mechanism for its effect on development, which may also explain its action in manic depression. (shrink)

In recent work MacPherson argues that the standard method of modeling belief logically, as a necessity operator in a modal logic, is doomed to fail. The problem with normal modal logics as logics of belief is that they treat believers as "ideal" in unrealistic ways (i.e., as omnidoxastic); however, similar problems re-emerge for candidate non-normal logics. The authors argue that logics used to model belief in artificial intelligence (AI) are also flawed in this way. But for AI systems, omnidoxasticity is (...) impossible because of their finite nature, and this fact can be exploited to produce operational models of fallible belief. The relevance of this point to various philosophical views about belief is discussed. (shrink)

Bruce Janz, Jessica Locke, and Cynthia Willett interact in this exchange with different aspects of Chakravarthi Ram-Prasad’s book Human Being, Bodily Being. Through “constructive inter-cultural thinking”, they seek to engage with Ram-Prasad’s “lower-case p” phenomenology, which exemplifies “how to think otherwise about the nature and role of bodiliness in human experience”. This exchange, which includes Ram-Prasad’s reply to their interventions, pushes the reader to reflect more about different aspects of bodiliness.

We present diverse evidence for the claim of Pullum and Rawlins (2007) that expressives behave differently from descriptives in constructions that enforce a particular kind of semantic identity between elements. Our data are drawn from a wide variety of languages and construction types, and they point uniformly to a basic linguistic distinction between descriptive content and expressive content (Kaplan 1999; Potts 2007).

Study of Tattvacintāmaṇididhiti of Raghunātha Śiromaṇi, commentary on Pakṣatā, portion of Tattvacintāmaṇi of Gaṅgeśa, dealing with the essential nature of proposition (pakṣatā), of Navya Nyāya school in Hindu philosophy.

This article presents material from my ethnographic study in Śringēri, south India, the site of a powerful 1200yearold Advaitic monastery that has been historically an interpreter of ancient Hindu moral treatises. A vibrant diverse local culture that provides plural sources of moral authority makes Sringeri a rich site for studying moral discourse. Through a study of two conversational narratives, this essay illustrates how the moral self is not an ossified product of written texts and codes, but is dynamic, gen dered, (...) and emergent, endowed with historical and political agency and an aesthetic capacity that mediates many normative sources to articulate "appropriate" conduct. In so doing, the essay shows the value of including oral narrative in ethical inquiry, especially in narrative ethics, which, for most part, has focused on written sources. (shrink)