Quantum Mechanics on Spacetime I: Spacetime State Realism

What ontology does realism about the quantum state suggest? The main extant view in contemporary philosophy of physics is wave-function realism. We elaborate the sense in which wave-function realism does provide an ontological picture; and defend it from certain objections that have been raised against it. However, there are good reasons to be dissatisfied with wave-function realism, as we go on to elaborate. This motivates the development of an opposing picture: what we call spacetime state realism; a view which takes the states associated to spacetime regions as fundamental. This approach enjoys a number of beneficial features, although, unlike wave-function realism, it involves non-separability at the level of fundamental ontology. We investigate the pros and cons of this non-separability, arguing that it is a quite acceptable feature; even one which proves fruitful in the context of relativistic covariance. A companion paper discusses the prospects for combining a spacetime-based ontology with separability, along lines suggested by Deutsch and HaydenComment: LaTeX; 29 pages, 1 Fig. Forthcoming in the British Journal for the Philosophy of Scienc

Context modeling and constraints binding in web service business processes

Context awareness is a principle used in pervasive services applications to enhance their exibility and adaptability to changing conditions and dynamic environments. Ontologies provide a suitable framework for context modeling and reasoning. We develop a context model for executable business processes { captured as an ontology for the web services domain. A web service description is attached to a service context profile, which is bound to the context ontology. Context instances can be generated dynamically at services runtime and are bound to context constraint services. Constraint services facilitate both setting up constraint properties and constraint checkers, which determine the dynamic validity of context instances. Data collectors focus on capturing context instances. Runtime integration of both constraint services and data collectors permit the business process to achieve dynamic business goals

Revising the UMLS Semantic Network

The integration of standardized biomedical terminologies into a single, unified knowledge representation system has formed a key area of applied informatics research in recent years. The Unified Medical Language System (UMLS) is the most advanced and most prominent effort in this direction, bringing together within its Metathesaurus a large number of distinct source-terminologies. The UMLS Semantic Network, which is designed to support the integration of these source-terminologies, has proved to be a highly successful combination of formal coherence and broad scope. We argue here, however, that its organization manifests certain structural problems, and we describe revisions which we believe are needed if the network is to be maximally successful in realizing its goals of supporting terminology integration

The GRA Beam-Splitter Experiments and Particle-Wave Duality of Light

Grangier, Roger and Aspect (GRA) performed a beam-splitter experiment to demonstrate the particle behaviour of light and a Mach-Zehnder interferometer experiment to demonstrate the wave behaviour of light. The distinguishing feature of these experiments is the use of a gating system to produce near ideal single photon states. With the demonstration of both wave and particle behaviour (in two mutually exclusive experiments) they claim to have demonstrated the dual particle-wave behaviour of light and hence to have confirmed Bohr's principle of complementarity. The demonstration of the wave behaviour of light is not in dispute. But we want to demonstrate, contrary to the claims of GRA, that their beam-splitter experiment does not conclusively confirm the particle behaviour of light, and hence does not confirm particle-wave duality, nor, more generally, does it confirm complementarity. Our demonstration consists of providing a detailed model based on the Causal Interpretation of Quantum Fields (CIEM), which does not involve the particle concept, of GRA's which-path experiment. We will also give a brief outline of a CIEM model for the second, interference, GRA experiment.Comment: 24 pages, 4 figure

On perception and ontology in the context of subjectivity and modern physics

I argue that our direct experience and some physical facts do not go well with an understanding of perception as a mechanism producing a representation of a ''truly'' outer world. Instead, it is much more coherent to treat what is traditionally considered an image in this context as a closed structure equipped in its own ontology, replacing the ''truly'' outer one from the point of view of an agent possessing it. In such a framework, the notion of existence is taken to be defined by consciousness in a way similar to qualia, making it subjective on the one hand, and reducing it to a tool on the other. This implies, in turn, that we need a form of mind-brain dualism; the best we can do in such circumstances about explaining consciousness as an epistemic device - a role intuitively imposing itself in a variety of situations - is to embed it in an abstract ontology merely serving the purpose of a ''true'' reality with the help of the mind-brain link. Obviously, the approach favors subjectivity as a foundation in the ontological sense. Objectivity is considered here only as a suitably understood product from an ''observer's'' point of view, although a functional and useful one. The paper is addressed to readers with interest in both the mind-body problem and ontological foundations of present-day physics, specifically quantum theory. The main conclusion can be absorbed without the quantum part, although it is a bit less convincing then