Since the 1930s, scientists studying the neurological disease scrapie had assumed that the infectious agent was a virus. By the mid 1960s, however, several unconventional properties had arisen that were difficult to reconcile with the standard viral model. Evidence for nucleic acid within the pathogen was lacking, and some researchers considered the possibility that the infectious agent consisted solely of protein. In 1982, Stanley Prusiner coined the term `prion' to emphasize the agent's proteinaceous nature. This infectious protein hypothesis was denounced (...) by many scientists as `heretical'.This essay asks why the concept of an infectious protein was considered controversial. Some biologists justified their evaluation of this hypothesis on the grounds that an infectious protein contradicted the `central dogma of molecular biology'. Others referred to vague theoretical constraints such as molecular biology's `theoretical structure' or `framework'. Examination of the objections raised by researchers reveals exactly what generalizations were being challenged by a protein model of infection.This two-part survey of scrapie and prion research reaches several conclusions: A theoretical framework is present in molecular biology, exerting its influence in hypothesis formation and evaluation; This framework consists of several related, yet separable, generalizations or `elements', including Francis Crick's Central Dogma and Sequence Hypothesis, plus notions concerning infection, replication, protein synthesis, and protein folding; The term `central dogma' has stretched beyond Crick's original 1958 definition to encompass at least two other `framework elements': replication and protein synthesis; and From the study of scrapie and related diseases, biological information has been delineated into at least two classes: sequential and what I call `conformational'.In Part I of this essay, a brief review of the central dogma, as outlined by both Francis Crick and James Watson, will be given. The developments in scrapie research from 1965 to 1972 will then be traced. This section will summarize many of the puzzling, non-viral-like properties of the scrapie agent. Alternative hypotheses to the viral explanation will also be presented, including early versions of a protein-only hypothesis. Part II of this essay will follow the developments in scrapie and prion research from the mid 1970s through 1991. The growing prominence of a protein-only model of infection will be balanced by continued objections from many researchers to a pathogen devoid of nucleic acid. These objections will help illuminate those generalizations in molecular biology that were indeed challenged by a protein-only model of infection. (shrink)

There is an abundant and growing feminist literature examining the implications of reproductive technologies that separate genetic, physiological, and social motherhood. The literature explains the development of these technologies in terms of the motivations of men, stressing the victimization of women by the medical and legal institutions and the commodification of these technologies. This article examines these technologies from a Marxist-Feminist perspective, locating their sources in the overall development of the forces of production; that is, in structural changes irreducible to (...) their microfoundations. In the process of changing the biological conditions of intergenerational social reproduction, these technologies have established the material basis for the structural separation between the mode of procreation and the mode of social and physical reproduction. These structural changes are generating new identities and forms of consciousness that clash with taken-for-granted ideas about motherhood. These differences are captured in feminist debates about the significance of these technologies. (shrink)

Developmental research on infants' categorization of living and nonliving objects finds that very young children are equally skilled in grouping such objects. The lack of a specialization for one type of object over another may be due to knowledge of function and the time frame for acquiring such knowledge.

The developing infant can accomplish all important perceptual tasks that an adult can, albeit with less skill or precision. Through infant perception research, infant responses to experiences enable researchers to reveal perceptual competence, test hypotheses about processes, and infer neural mechanisms, and researchers are able to address age-old questions about perception and the origins of knowledge.In Development of Perception in Infancy: The Cradle of Knowledge Revisited, Martha E. Arterberry and Philip J. Kellman study the methods and data of scientific (...) research on infant perception, introducing and analyzing topics through philosophical, theoretical, and historical contexts. Infant perception research is placed in a philosophical context by addressing the abilities with which humans appear to be born, those that appear to emerge due to experience, and the interaction of the two. The theoretical perspective is informed by the ecological tradition, and from such a perspective the authors focus on the information available for perception, when it is used by the developing infant, the fit between infant capabilities and environmental demands, and the role of perceptual learning. Since the original publication of this book in 1998, Arterberry and Kellman address in addition the mechanisms of change, placing the basic capacities of infants at different ages and exploring what it is that infants do with this information. Significantly, the authors feature the perceptual underpinnings of social and cognitive development, and consider two examples of atypical development - congenital cataracts and Autism Spectrum Disorder. Professionals and students alike will find this book a critical resource to understanding perception, cognitive development, social development, infancy, and developmental cognitive neuroscience, as research on the origins of perception has changed forever our conceptions of how human mental life begins. (shrink)

The “Perky effect” is the interference of visual imagery with vision. Studies of this effect show that visual imagery has more than symbolic properties, but these properties differ both spatially (including “pictorially”) and temporally from those of vision. We therefore reject both the literal picture-in-the-head view and the entirely symbolic view.

Children enter the world curiously hard-wired for creativity and imagination. After a few short years of school, something drastically changes for them. Why? There is an unmistakable and deliberate attempt to control the learning of young people who find themselves sitting in our schools. The industrial model of schooling has taken its toll and victims without remorse. It programs curious young minds to become helpless, dependent, and compliant. It is manipulation and malpractice, but few seem to notice or care. After (...) years of observing and participating in some of these questionable practices herself, Evonne decided it was time to tell the truth about schools. With a credible and strong voice, Evonne tackles the “sacred school rituals” that are rarely questioned and widely accepted as normal. She transparently leads the reader through firmly-held and often faulty assumptions about schooling practices. She offers common sense solutions that challenge us to re-imagine how we do school in this country. With strong conviction, passion, and a call to action, she encourages us to hear and listen to the voices of our children who are crying out for the freedom to learn. (shrink)

This paper contributes to the foundations of a theory of rational choice for artificial agents in dynamic environments. Our work is developed within a theoretical framework, originally due to Bratman, that models resource-bounded agents as operating against the background of some current set of intentions, which helps to frame their subsequent reasoning. In contrast to the standard theory of rational choice, where options are evaluated in isolation, we therefore provide an analysis of situations in which the options presented to an (...) agent are evaluated against a background context provided by the agent’s current plans—commitments to future activities, which may themselves be only partially specified. The interactions between the new options and the background context can complicate the task of evaluating the option, rendering it either more or less desirable in context than it would have been in isolation.  2001 Elsevier Science B.V. All rights reserved. (shrink)

Meditation is an umbrella term for a number of mental training practices designed to improve the monitoring and regulation of attention and emotion. Some forms of meditation are now being used for clinical intervention. To accompany the increased clinical interest in meditation, research investigating the neural basis of these practices is needed. A central hypothesis of contemplative neuroscience is that meditative states, which are unique on a phenomenological level, differ on a neurophysiological level. To identify the electrophysiological correlates of meditation (...) practice, the electrical brain activity of highly skilled meditators engaging in one of six meditation styles was recorded. A mind-wandering task served as a control. Lempel–Ziv complexity showed differences in nonlinear brain dynamics during meditation compared with mind wandering, suggesting that meditation, regardless of practice, affects neural complexity. In contrast, there were no differences in power spectra at six different frequency bands, likely due to the fact that participants engaged in different meditation practices. Finally, exploratory analyses suggest neurological differences among meditation practices. These findings highlight the importance of studying the electroencephalography correlates of different meditative practices. (shrink)

Buddhisms and Deconstructions considers the connection between Buddhism and Derridean deconstruction, focusing on the work of Robert Magliola. Fourteen distinguished contributors discuss deconstruction and various Buddhisms—Indian, Tibetan, and Chinese —followed by an afterword in which Magliola responds directly to his critics.

The author explains that his previous philosophical arguments for compatibilism provide a robust basis for ethical and legal responsibility. He defends entity causation, arguing that no coherent model of the universe, including human action, can be formulated that rejects entities as the nexus of identity and causality. Finally, he contends, ontological compatibilism and ethical compatibilism are both best supported by a more fundamental methodological compatibilism of philosophical and scientific approaches to seeking truth.

The author provides another metaphysical argument to bolster his thesis of the logical harmony of determinism and volition. He shows how the typical mainstream and Objectivist doctrine of “libertarian” free will commits the same logical error as the Sophist attacks on the Law of Non-Contradiction—namely, an out-of-context interpretation of, respectively, the Law of Causality and the Law of Identity as being unconditional absolutes, which they are not and cannot be.

In the original publication of the article, errors in the production stages resulted in Vanessa Munro being listed as sole author.

The author assures readers that Chris Matthew Sciabarra has met all Aristotelian requirements in full, providing not one but two definitions of “dialectics,” which, as the art of context-keeping, is indeed an essential part of Ayn Rand's philosophical method. He shows how Sciabarra's definitional process compares quite favorably in terms of timeliness, transparency, and benevolence to that of Rand and other Objectivists, and notes that Sciabarra's overriding concern, notwithstanding his obvious great respect for Rand's substantive philosophical achievements, has been to (...) identify and clarify the methods she and other thinkers have used to profound benefit. (shrink)

In this third installment of his series on key, underappreciated ideas in Ayn Rand's epistemology, the author discusses the nature of differentiation and integration as the functional essence of consciousness and applies that insight to various cognitive and noncognitive processes of awareness, with a special emphasis on logic and illogic. He offers an extended analysis of the fallacies of “Frozen Abstraction” and “False Alternative,” as well as critiques of a long-standing Objectivist conflation of falsity and contradiction and a relatively more (...) recent Objectivist error, the fallacy of “genuine awareness.”. (shrink)

The cognitive disorders that follow brain damage are an important source of insights into the neural bases of human thought. This work offers state-of-the-art reviews of the patient-based approach to central issues in cognitive neuroscience by leaders in the field.

Despite its theoretical importance, little is known about how semantic memory structure facilitates and constrains creative idea generation. We examine whether the semantic richness of a concept has both benefits and costs to creative idea generation. Specifically, we tested whether cue set size—an index of semantic richness reflecting the average number of elements associated with a given concept—impacts the quantity (fluency) and quality (originality) of responses generated during the Alternate Uses Task (AUT). Across four studies, we show that low-association, sparse, (...) AUT cues benefit originality at the cost of fluency compared to high-association, rich, AUT cues. Furthermore, we found an interaction with individual differences in fluid intelligence in the low-association AUT cues, suggesting that constraints of sparse semantic knowledge can be overcome with top-down intervention. Our findings indicate that semantic richness differentially impacts the quality and quantity of generated ideas, and that cognitive control processes can facilitate idea production when conceptual knowledge is limited. (shrink)

The author explains how Rand was absolutely correct in saying that Aristotle “stated the formula” of the Law of Identity. He corrects long-standing faulty Thomist criticisms on this issue and gives due credit to thinkers such as Antonius Andreas, Leibniz, and William Hamilton. The author further contends that the gradual shift in Objectivist usage of the Law of Identity tacitly ratifies these erroneous criticisms and has actually contributed to the failure of Objectivist thinkers to develop Rand's concept theory into a (...) valid model of propositions and syllogisms. (shrink)