5,892 research outputs found
Richard Swinburne's arguments for substance dualism.
This dissertation is a contribution to debates in the philosophy of mind and of personal identity. It presents a critical account of arguments for substance dualism to be found in Richard Swinburne’s Mind, Brain, and Free Will (2013). Swinburne’s principal claim is that persons are essentially pure mental substances whose sameness over time is constituted by a unique ‘thisness’. A human being consists of two parts: a contingent part, the body (physical substance), and an essential part, the mind or soul (pure mental substance) which is characterised by ‘thisness’. It is, on this account, logically and metaphysically possible that a person can be disembodied. The dissertation analyses Swinburne’s relationship to other major theories in the philosophy of mind, especially his critical rejection of physicalism and materialism. Swinburne mounts a defence of substance dualism by building upon some key fundamental ideas and principles. The first area of discussion is Swinburne’s novel contention that any satisfactory account of the mental and physical lives of human beings must meet the requirements of a ‘metacriterion’ which supports his division of the world into physical and mental substances, properties, events and time. Swinburne underpins the metacriterion by proposing a canonical vocabulary based on a theory of informative designators. The main line of attack here is on the inadequacy of Swinburne’s theory of designation as a convincing theory of how language works and is used. Secondly, the metacriterion is complemented by a theory of privileged access of subjects to their mental events which is not available to others. Criticism of this doctrine is derived from the work of Austin, Ryle and Wittgenstein. Thirdly, Swinburne deploys the principles of credulity and testimony to defend the causal interaction of mental and physical substances. He claims the principles are fundamental, a priori, and epistemic. The argument of the dissertation is that they are none of these things. My conclusion is that Swinburne’s principal arguments for substance dualism and personal identity are unsound
Decoding sequential vs non-sequential two-photon double ionization of helium using nuclear recoil
Above 54.4 eV, two-photon double ionization of helium is dominated by a
sequential absorption process, producing characteristic behavior in the single
and triple differential cross sections. We show that the signature of this
process is visible in the nuclear recoil cross section, integrated over all
energy sharings of the ejected electrons, even below the threshold for the
sequential process. Since nuclear recoil momentum imaging does not require
coincident photoelectron measurement, the predicted images present a viable
target for future experiments with new short-pulse VUV and soft X-ray sources.Comment: 4 pages, 3 figure
The stability of liquid lubricated journal bearings
The dynamio characteristics of journal bearings have been predicted by solving Reynolds equation with a common cavitation model. A perturbation analysis has been used to express the equations governing the fluid film pressure and cavitation region state in terms of a dynamic journal displacement vector. The use of these equations has been demonstrated on the long and short bearing approximations. The stability performance has been predicted for both rigid and flexible bearing systems. A perspex test bearing has been used to observe cavitation under steady and dynamio loads, and a high speed test apparatus was developed for the measurement of lubricating film performance at whirl onset conditions. Although the test results were consistent and repeatable, the stability performance of the bearings tested was substantially less than the predictions of the simple bearing theory and other workers results. It is thought that the poor performance was due to oil starvation
Cancer mortality in Native Americans in North Carolina.
his paper describes age-adjusted mortality from malignant neoplasms for Native Americans in North Carolina for 1968-72 and 1978-82. Sex-specific standardized mortality ratios were calculated from death certificate data, using the cancer mortality experience of White North Carolinians to obtain the number of expected deaths. For most categories and specific sites of cancer, mortality was at or below the expected level, but higher than expected mortality was found for genitourinary cancers in males (SMR=1.62,95%CI=1.15,2.21)forthe1978-82period;withinthis category, there was a higher than expected level of mortality from prostate cancer (SMR = 2.00; 95% CI = 1.36, 2.83) and cancer of the penis and other male genital organs (SMR = 9.09; 95% CI = 1.10, 32.84). Female Native Americans had an elevated mortality from cervical cancer (SMR = 2.27, 95% CI = 1.09, 4.17) for the 1968-72 period only. Originally published American Journal of Public Health, Vol. 80, No. 8, Aug 199
Emergent Spacetime in Quantum Lattice Models
Many quantum lattice models have an emergent relativistic description in
their continuum limit. The celebrated example is graphene, whose continuum
limit is described by the Dirac equation on a Minkowski spacetime. Not only
does the continuum limit provide us with a dictionary of geometric observables
to describe the models with, but it also allows one to solve models that were
otherwise analytically intractable. In this thesis, we investigate novel
features of this relativistic description for a range of quantum lattice
models. In particular, we demonstrate how to generate emergent curved
spacetimes and identify observables at the lattice level which reveal this
emergent behaviour, allowing one to simulate relativistic effects in the
laboratory. We first study carbon nanotubes, a system with an edge, which
allows us to test the interesting feature of the Dirac equation that it allows
for bulk states with support on the edges of the system. We then study Kitaev's
honeycomb model which has a continuum limit describing Majorana spinors on a
Minkowski spacetime. We show how to generate a non-trivial metric in the
continuum limit of this model and how to observe the effects of this metric and
its corresponding curvature in the lattice observables, such as Majorana
correlators, Majorana zero modes and the spin densities. We also discuss how
lattice defects and gauge fields at the lattice level can
generate chiral gauge fields in the continuum limit and we reveal their
adiabatic equivalence. Finally, we discuss a chiral modification of the 1D XY
model which makes the model interacting and introduces a non-trivial phase
diagram. We see that this generates a black hole metric in the continuum limit,
where the inside and outside of the black hole are in different phases. We then
demonstrate that by quenching this model we can simulate Hawking radiation.Comment: 145 pages, 32 figures, Ph.D. thesi
The Populations of Comet-Like Bodies in the Solar system
A new classification scheme is introduced for comet-like bodies in the Solar
system. It covers the traditional comets as well as the Centaurs and
Edgeworth-Kuiper belt objects. At low inclinations, close encounters with
planets often result in near-constant perihelion or aphelion distances, or in
perihelion-aphelion interchanges, so the minor bodies can be labelled according
to the planets predominantly controlling them at perihelion and aphelion. For
example, a JN object has a perihelion under the control of Jupiter and aphelion
under the control of Neptune, and so on. This provides 20 dynamically distinct
categories of outer Solar system objects in the Jovian and trans-Jovian
regions. The Tisserand parameter with respect to the planet controlling
perihelion is also often roughly constant under orbital evolution. So, each
category can be further sub-divided according to the Tisserand parameter. The
dynamical evolution of comets, however, is dominated not by the planets nearest
at perihelion or aphelion, but by the more massive Jupiter. The comets are
separated into four categories -- Encke-type, short-period, intermediate and
long-period -- according to aphelion distance. The Tisserand parameter
categories now roughly correspond to the well-known Jupiter-family comets,
transition-types and Halley-types. In this way, the nomenclature for the
Centaurs and Edgeworth-Kuiper belt objects is based on, and consistent with,
that for comets.Comment: MNRAS, in press, 11 pages, 6 figures (1 available as postscript, 5 as
gif). Higher resolution figures available at
http://www-thphys.physics.ox.ac.uk/users/WynEvans/preprints.pd
A New Kinematic Distance Estimator to the LMC
The distance to the Large Magellanic Cloud (LMC) can be directly determined
by measuring three of its properties, its radial-velocity field, its mean
proper motion, and the position angle \phi_ph of its photometric line of nodes.
Statistical errors of 2% are feasible based on proper motions obtained with any
of several proposed astrometry satellites, the first possibility being the
Full-Sky Astrometric Mapping Explorer (FAME). The largest source of systematic
error is likely to be in the determination of \phi_ph. I suggest two
independent methods to measure \phi_ph, one based on counts of clump giants and
the other on photometry of clump giants. I briefly discuss a variety of methods
to test for other sources of systematic errors.Comment: submitted to ApJ, 13 page
Discovery of a very X-ray luminous galaxy cluster at z=0.89 in the WARPS survey
We report the discovery of the galaxy cluster ClJ1226.9+3332 in the Wide
Angle ROSAT Pointed Survey (WARPS). At z=0.888 and L_X=1.1e45 erg/s (0.5-2.0
keV, h_0=0.5) ClJ1226.9+3332 is the most distant X-ray luminous cluster
currently known. The mere existence of this system represents a huge problem
for Omega_0=1 world models.
At the modest (off-axis) resolution of the ROSAT PSPC observation in which
the system was detected, ClJ1226.9+3332 appears relaxed; an off-axis HRI
observation confirms this impression and rules out significant contamination
from point sources. However, in moderately deep optical images (R and I band)
the cluster exhibits signs of substructure in its apparent galaxy distribution.
A first crude estimate of the velocity dispersion of the cluster galaxies based
on six redshifts yields a high value of 1650 km/s, indicative of a very massive
cluster and/or the presence of substructure along the line of sight. While a
more accurate assessment of the dynamical state of this system requires much
better data at both optical and X-ray wavelengths, the high mass of the cluster
has already been unambiguously confirmed by a very strong detection of the
Sunyaev-Zel'dovich effect in its direction (Joy et al. 2001).
Using ClJ1226.9+3332 and ClJ0152.7-1357 (z=0.835), the second-most distant
X-ray luminous cluster currently known and also a WARPS discovery, we obtain a
first estimate of the cluster X-ray luminosity function at 0.8<z<1.4 and
L_X>5e44 erg/s. Using the best currently available data, we find the comoving
space density of very distant, massive clusters to be in excellent agreement
with the value measured locally (z<0.3), and conclude that negative evolution
is not required at these luminosities out to z~1. (truncated)Comment: accepted for publication in ApJ Letters, 6 pages, 2 figures, uses
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