127 research outputs found

    Linguistic meta-theory the formal and empirical conditions of acceptability of linguistic theories and descriptions

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    Most linguists acknowledge, explicitly or implicitly, the relevance of epistemological questions in linguistics but relatively few have given more than a cursory, ad hoc or incomplete consideration to them. The work of one of those few, Jan Mulder, forms the starting point for much of the present discussion. Epistemological considerations arise in many contexts in linguistics and in many guises. It is an epistemological matter whenever we test the adequacy of a description or the acceptability of a theory. Epistemological considerations are latent whenever we discuss the form or the content of linguistic theories and descriptions or their interrelations. The comparison of different approaches to linguistics inevitably raises epistemological questions concerning our approach to linguistics or our presuppositions about it. These questions are of a general nature and transcend questions about particular linguistic theories and descriptions. These epistemological questions force us to consider what we take linguistics to be. In considering questions of the type mentioned we are forced, for example, to analyse what we mean by a "linguistic theory", a "linguistic description" and what phenomena we are aiming to understand. We are, furthermore, forced to analyse the constraints which a scientific attitude places upon linguistic theorising and description-building. It is these questions concerning the acceptability of linguistic theories and descriptions which we call linguistic meta-theory. This thesis falls into five main parts. Firstly, in Chapter One, we consider the nature and scope of linguistic meta-theory. Secondly, in Chapter Two, we look at a number of previous approaches to the subject. Other important contributions are discussed as they arise in the text. Thirdly, in Chapters Three and Four, we consider in detail the major meta-theoretical distinctions in linguistics and their consequences. In particular, we distinguish linguistic theories from linguistic descriptions and discuss the nature of linguistic phenomena. The view is put forward that linguistics is a scientific subject. The meaning of this assertion is analysed and the interrelations of linguistic theories, descriptions and phenomena are considered in the light of this analysis. The main epistemological requirement that is put forward and defended is that of the empiricism of linguistics. Certain changes in our view of the philosophy of science and in our view of the form of linguistic theories and descriptions follow from the conjunction of these major meta-theoretical positions. Fourthly, we consider the main meta-theoretical considerations concerning theories (Chapter Five) and reject a widespread view of linguistic theory as a non-empirical study (Chapter Six) and we consider the main meta-theoretical conditions relating to linguistic descriptions and some practical examples of description -building consonant with the general positions adopted in Chapter Seven. In Chapter Eight, we look at a concrete example of theory-building in the light of the meta-theoretical conditions of acceptability previously set up. We are especially concerned to show how a theory can meet the condition of being "applicable" or "indirectly scientific" through the establishment of acceptable empirical descriptions consonant with the meta-theoretical conditions on descriptions considered earlier. The view that linguistics is a science implies that we must be concerned with the empirical testing of descriptions and, so, the fifth part of the work is devoted to methodology. In Chapter Nine, we defend the role and necessity of methodology in linguistics and set up the logical framework of relations between the methodology and theory descriptions and phenomena. In Chapter Ten, we examine two of the known types of empirical testing and their shortcomings. Finally, in Chapter Eleven, we give an example of the successful and correct application of a methodology in order to bring out the nature of empirical testing and to demonstrate its feasibility within a scientific linguistics of the sort we imagine

    Observational constraints on Rastall's cosmology

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    Rastall's theory is a modification of General Relativity, based on the non-conservation of the stress-energy tensor. The latter is encoded in a parameter γ\gamma such that γ=1\gamma = 1 restores the usual νTμν=0\nabla_\nu T^{\mu\nu} = 0 law. We test Rastall's theory in cosmology, on a flat Robertson-Walker metric, investigating a two-fluid model and using the type Ia supernovae Constitution dataset. One of the fluids is pressureless and obeys the usual conservation law, whereas the other is described by an equation of state px=wxρxp_x = w_x\rho_x, with wxw_x constant. The Bayesian analysis of the Constitution set does not strictly constrain the parameter γ\gamma and prefers values of wxw_x close to -1. We then address the evolution of small perturbations and show that they are dramatically unstable if wx1w_x \neq -1 and γ1\gamma \neq 1, i.e. General Relativity is the favored configuration. The only alternative is wx=1w_x = -1, for which the dynamics becomes independent from γ\gamma.Comment: Latex file, 14 pages, 6 figures in eps format. Substantial modifications performed, main conclusions change

    Quantum-classical transition in Scale Relativity

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    The theory of scale relativity provides a new insight into the origin of fundamental laws in physics. Its application to microphysics allows us to recover quantum mechanics as mechanics on a non-differentiable (fractal) spacetime. The Schrodinger and Klein-Gordon equations are demonstrated as geodesic equations in this framework. A development of the intrinsic properties of this theory, using the mathematical tool of Hamilton's bi-quaternions, leads us to a derivation of the Dirac equation within the scale-relativity paradigm. The complex form of the wavefunction in the Schrodinger and Klein-Gordon equations follows from the non-differentiability of the geometry, since it involves a breaking of the invariance under the reflection symmetry on the (proper) time differential element (ds - ds). This mechanism is generalized for obtaining the bi-quaternionic nature of the Dirac spinor by adding a further symmetry breaking due to non-differentiability, namely the differential coordinate reflection symmetry (dx^mu - dx^mu) and by requiring invariance under parity and time inversion. The Pauli equation is recovered as a non-relativistic-motion approximation of the Dirac equation.Comment: 28 pages, no figur

    Scalar models for the generalized Chaplygin gas and the structure formation constraints

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    The generalized Chaplygin gas model represents an attempt to unify dark matter and dark energy. It is characterized by a fluid with an equation of state p=A/ραp = - A/\rho^\alpha. It can be obtained from a generalization of the DBI action for a scalar, tachyonic field. At background level, this model gives very good results, but it suffers from many drawbacks at perturbative level. We show that, while for background analysis it is possible to consider any value for α\alpha, the perturbative analysis must be restricted to positive values of α\alpha. This restriction can be circumvented if the origin of the generalized Chaplygin gas is traced back to a self-interacting scalar field, instead of the DBI action. But, in doing so, the predictions coming from formation of large scale structures reduce the generalized Chaplygin gas model to a kind of quintessence model, and the unification scenario is lost, if the scalar field is the canonical one. However, if the unification condition is imposed from the beginning as a prior, the model may remain competitive. More interesting results, concerning the unification program, are obtained if a non-canonical self-interacting scalar field, inspired by Rastall's theory of gravity, is imposed. In this case, an agreement with the background tests is possible.Comment: Latex file, 25 pages, 33 figures in eps format. New section on scalar models. Accepted for publication in Gravitation&Cosmolog

    Analyzing three-player quantum games in an EPR type setup

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    We use the formalism of Clifford Geometric Algebra (GA) to develop an analysis of quantum versions of three-player non-cooperative games. The quantum games we explore are played in an Einstein-Podolsky-Rosen (EPR) type setting. In this setting, the players' strategy sets remain identical to the ones in the mixed-strategy version of the classical game that is obtained as a proper subset of the corresponding quantum game. Using GA we investigate the outcome of a realization of the game by players sharing GHZ state, W state, and a mixture of GHZ and W states. As a specific example, we study the game of three-player Prisoners' Dilemma.Comment: 21 pages, 3 figure

    Interaction of convective organisation with monsoon precipitation, atmosphere, surface and sea: the 2016 INCOMPASS field campaign in India

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    The INCOMPASS field campaign combines airborne and ground measurements of the 2016 Indian monsoon, towards the ultimate goal of better predicting monsoon rainfall. The monsoon supplies the majority of water in South Asia, but forecasting from days to the season ahead is limited by large, rapidly developing errors in model parametrizations. The lack of detailed observations prevents thorough understanding of the monsoon circulation and its interaction with the land surface: a process governed by boundary-layer and convective-cloud dynamics. INCOMPASS used the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft for the first project of this scale in India, to accrue almost 100 hours of observations in June and July 2016. Flights from Lucknow in the northern plains sampled the dramatic contrast in surface and boundary layer structures between dry desert air in the west and the humid environment over the northern Bay of Bengal. These flights were repeated in pre-monsoon and monsoon conditions. Flights from a second base at Bengaluru in southern India measured atmospheric contrasts from the Arabian Sea, over the Western Ghats mountains, to the rain shadow of southeast India and the south Bay of Bengal. Flight planning was aided by forecasts from bespoke 4km convection-permitting limited-area models at the Met Office and India's NCMRWF. On the ground, INCOMPASS installed eddy-covariance flux towers on a range of surface types, to provide detailed measurements of surface fluxes and their modulation by diurnal and seasonal cycles. These data will be used to better quantify the impacts of the atmosphere on the land surface, and vice versa. INCOMPASS also installed ground instrumentation supersites at Kanpur and Bhubaneswar. Here we motivate and describe the INCOMPASS field campaign. We use examples from two flights to illustrate contrasts in atmospheric structure, in particular the retreating mid-level dry intrusion during the monsoon onset
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