In the modal literature various notions of completeness have been studied for normal modal logics. Four of these are defined here, viz. (plain) completeness, first-order completeness, canonicity and possession of the finite model property — and their connections are studied. Up to one important exception, all possible inclusion relations are either proved or disproved. Hopefully, this helps to establish some order in the jungle of concepts concerning modal logics. In the course of the exposition, the interesting properties of first-order definability (...) and preservation under ultrafilter extensions are introduced and studied as well. (shrink)

The statistical properties of a single quantum object and an ensemble of independent such objects are considered in detail for two-level systems. Computer simulations of dynamic zero-point quantum fluctuations for a single quantum object are reported and compared with analytic solutions for the ensemble case.

Gabbay has gathered an enormous amount of results; some of them important and novel, others important but already known, many rather routine, however. The organization of this material shows grave defects, both in the exposition and in its logical structure. Intensional logic appears as a vast collection of (often duplicated) loosely connected results. This may be a true reflection of the present state of the subject, but it does not contribute to a better understanding of it, let alone advance it.

In the Laura Ashworth case in 2008, the Human Tissue Authority considered itself bound to overturn a deceased daughter's alleged wish that one of her kidneys should go to her mother, who at the time had end stage kidney failure and was on dialysis. 12 This was so even though Laura's earlier wish to be a living donor would most likely have been authorised, had the formal assessment process begun. The decision provoked much criticism. The recent Department of Health document (...) Requested Allocation of a Deceased Donor Organ, published 29 March 2010, developed by the UK health administrations together with the HTA and NHS Blood and Transplant , which is the main organ allocation body in the UK, seeks to resolve this ethical dilemma by setting out the circumstances in which requests for such deceased donations may be acceptable. 3 The most important conditions appear to be:a. the donation must be unconditional in nature;b. there must be …. (shrink)

Transplantation research on samples and organs from deceased donors in England, Wales and Northern Ireland is under threat. The key problems relate to difficulties encountered in gaining consent for research projects, as distinct from consent to donation for clinical transplantation. They are due partly to the terms of the Human Tissue Act 2004 (the 2004 Act), and partly to its interpretation by the Human Tissue Authority (HTA). They include excessive interaction with donor representatives regarding ‘informed consent’ to research projects, uncertainty (...) as to the scope and duration of a donor's ‘authority’ over an organ, and restrictions caused by the apparent need for licensing of transplantation research under the 2004 Act, combined with lack of certainty, or guidance, as to the distinction between ‘research’, which requires a licence, and ‘service development’, which does not. In our view this confusion hinders and deters Specialist Nurses for Organ Donation in approaching donor representatives and discussing possible research projects with them. It has also, as we have reported elsewhere, led to abandonment of research projects for fear of liability, despite both Research Ethics Committee (REC) approval and donor consent. Such problems do not seem to occur under the transplant laws of most other comparable jurisdictions. The Transplantation Ethics Symposium, ‘The ethics of organ retrieval: goals, rights and responsibilities’, hosted by the MRC Centre for Transplantation at King's College London in December 2010, revealed that many senior clinicians and researchers, administrators, and lawyers are both unclear and in disagreement concerning the effects of the 2004 Act and the extent to which it is adhered to or ignored in practice. In this paper we examine the difficulties encountered and suggest solutions based on a less restrictive interpretation of the 2004 Act, or, more probably, a regulatory change under its authority. We propose that, in the long term, a law which includes consent for REC-approved research within the general consent for organ donation and transplantation seems preferable to the present system, both ethically and in practical terms. (shrink)

Highlights the roles of intention and intentionality in social cognition.

Visual imagery is a form of sensory imagination, involving subjective experiences typically described as similar to perception, but which occur in the absence of corresponding external stimuli. We used the Activation Likelihood Estimation algorithm (ALE) to identify regions consistently activated by visual imagery across 40 neuroimaging studies, the first such meta-analysis. We also employed a recently developed multi-modal parcellation of the human brain to attribute stereotactic co-ordinates to one of 180 anatomical regions, the first time this approach has been combined (...) with the ALE algorithm. We identified a total 634 foci, based on measurements from 464 participants. Our overall comparison identified activation in the superior parietal lobule, particularly in the left hemisphere, consistent with the proposed ‘top-down’ role for this brain region in imagery. Inferior premotor areas and the inferior frontal sulcus were reliably activated, a finding consistent with the prominent semantic demands made by many visual imagery tasks. We observed bilateral activation in several areas associated with the integration of eye movements and visual information, including the supplementary and cingulate eye fields (SCEFs) and the frontal eye fields (FEFs), suggesting that enactive processes are important in visual imagery. V1 was typically activated during visual imagery, even when participants have their eyes closed, consistent with influential depictive theories of visual imagery. Temporal lobe activation was restricted to area PH and regions of the fusiform gyrus, adjacent to the fusiform face complex (FFC). These results provide a secure foundation for future work to characterise in greater detail the functional contributions of specific areas to visual imagery. (shrink)

Different explanations of color vision favor different philosophical positions: Computational vision is more compatible with objectivism (the color is in the object), psychophysics and neurophysiology with subjectivism (the color is in the head). Comparative research suggests that an explanation of color must be both experientialist (unlike objectivism) and ecological (unlike subjectivism). Computational vision's emphasis on optimally prespecified features of the environment (i.e., distal properties, independent of the sensory-motor capacities of the animal) is unsatisfactory. Conceiving of visual perception instead as the (...) visual guidance of activity in an environment that is determined largely by that very activity suggests new directions for research. (shrink)

Schelling's first systematic attempt to articulate a complete philosophy of nature.