13,622 research outputs found

    Millican on the Ontological Argument

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    Peter Millican (2004) provides a novel and elaborate objection to Anselm’s ontological argument. Millican thinks that his objection is more powerful than any other because it does not dispute contentious ‘deep philosophical theories’ that underlie the argument. Instead, it tries to reveal the ‘fatal flaw’ of the argument by considering its ‘shallow logical details’. Millican’s objection is based on his interpretation of the argument, according to which Anselm relies on what I call the ‘principle of the superiority of existence’ (PSE). I argue that (i) the textual evidence Millican cites does not provide a convincing case that Anselm relies on PSE and that, moreover, (ii) Anselm does not even need PSE for the ontological argument. I introduce a plausible interpretation of the ontological argument that is not vulnerable to Millican’s objection and conclude that even if the ontological argument fails, it does not fail in the way Millican thinks it does

    Cosmological Symmetry Breaking and Generation of Electromagnetic Field

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    Cosmological phase transitions accompanied by some kind of symmetry breaking would cause the creation of topological defects and the resulting production of primordial magnetic field. Moreover, such a procedure inevitably affects the cosmic background radiation and it may be observed today. Motivated by the existence of stabilized embedded defects in the standard model of elementary interactions, we discuss their application to the cosmological electromagnetic field generation

    Identification and Estimation of Partial Effects with Proxy Variables

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    I develop a new identification approach for partial effects in nonseparable models with endogeneity. I use a proxy variable for the unobserved heterogeneity correlated with the endogenous variable to construct a valid control function, where the definition of a proxy variable is the same as in the measurement error literature. The identifying assumptions are distinct from existing methods, in particular instrumental variables and selection on observables approaches, and I provide an alternative identification strategy in settings where existing approaches are not applicable. Building on the identification result, I consider three estimation approaches, ranging from nonparametric to flexible parametric methods, and characterize asymptotic properties of the proposed estimators.Comment: 48 pages with the appendi

    Scaling Distribution of Axionic Strings and Estimation of Axion Density from Axionic Domain Walls

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    The damping of the axionic string motion due to the surrounding plasma is estimated by a detailed calculation of the fermion scatter from a global string and it is shown that the friction force on the string can be neglected before the axionic domain wall formation in most cases, which is one of the important necessary conditions for the scaling distribution of the strings. The energy density of the axion produced by the collapse of the axionic domain walls is also evaluated using the axionic string distribution, and it is found to be larger or at least comparable to the axion density which originates from the axionic strings.Comment: 20 pages (LaTeX), 3 figures, eclepsf.sty, revised figure

    Is There a Shallow Logical Refutation of the Ontological Argument?

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    The beauty of Anselm’s ontological argument is, I believe, that no matter how one approaches it, one cannot refute it without making a significant metaphysical assumption, one that is likely to be contentious in its own right. Peter Millican disagrees. He introduces an objection according to which one can refute the argument merely by analysing its shallow logical details, without making any significant metaphysical assumption. He maintains, moreover, that his objection does not depend on a specific reading of the relevant Anselmian text; in fact, Millican claims that his objection is applicable to every version of the ontological argument. In this paper, I argue that millican’s objection does not succeed, because, contrary to what he says, in order to justify his objection he does have to make a deep metaphysical assumption and rely on a specific reading of Anselm’s text

    Identification and estimation of group-level partial effects

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    The influence of general-relativity effects, dynamical tides and collisions on planet-planet scattering close to the star

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    Planet--Planet scattering is an efficient and robust dynamical mechanism for producing eccentric exoplanets. Coupled to tidal interactions with the central star, it can also explain close--in giant planets on circularized and potentially misaligned orbits. We explore scattering events occurring close to the star and test if they can reproduce the main features of the observed orbital distribution of giant exoplanets on tight orbits.In our modeling we exploit a numerical integration code based on the Hermite algorithm and including the effects of general relativity, dynamical tides and two--body collisions.We find that P--P scattering events occurring in systems with three giant planets initially moving on circular orbits close to their star produce a population of planets similar to the presently observed one, including eccentric and misaligned close--in planets. The contribution of tides and general relativity is relevant in determining the final outcome of the chaotic phase. Even if two--body collisions dominate the chaotic evolution of three planets in crossing orbits close to their star, the final distribution shows a significant number of planets on eccentric orbits. The highly misaligned close--in giant planets are instead produced by systems where the initial semi--major axis of the inner planet was around 0.2 au or beyond.Comment: Accepted for publication on A&

    Higgsless Gauge Symmetry Breaking with a Large Mass Hierarchy

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    We propose a mechanism of Higgsless gauge symmetry breaking with a large mass hierarchy. We consider a 5D gauge theory on an orbifold S1/Z2S^1/Z_2. The gauge symmetry is broken by orbifolding and also nontrivial boundary conditions at fixed points. All 4D modes which survive at low energies are found to be localized around fixed points. Supersymmetry plays an important role in our mechanism. The tree-level unitarity in our model is briefly discussed.Comment: 9 pages, 1 figure, PTPTe
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