31,042 research outputs found
Authority without privilege: How to be a Dretskean conciliatory skeptic on self-knowledge
Dretske is a “conciliatory skeptic” on self-knowledge. Take some subject S such that S thinks that P and S knows that she has thoughts. Dretske’s theory can be put as follows: S has a privileged way of knowing what she thinks, but she has no privileged way of knowing that she thinks it. There is much to be said on behalf of conciliatory skepticism and Dretske’s defense of it. We aim to show, however, that Dretske’s defense fails, in that if his defense of CS’s skeptical half succeeds, then his defense of CS’s conciliatory half fails. We then suggest a potential way forward. We suggest in particular that the correct way of being a Dretskean conciliatory skeptic is to deny that S has a privileged way of knowing about her thoughts, but to grant that she is nonetheless an authority on her thoughts
United States Courts and the Optimal Deterrence of International Cartels: A Welfarist Perspective on Empagran
SWIFT J1749.4-2807: A neutron or quark star?
We investigate an unique accreting millisecond pulsar with X-ray eclipses,
SWIFT J1749.42807 (hereafter J1749), and try to limit the binary system by
various methods including that of the Roche lobe, the mass-radius relations of
both a main sequence (MS) and a white dwarf (WD) companion stars, as well as
the measured mass function of the pulsar. The calculations are based on the
assumption that the radius of the companion star has reached its Roche radius
(or at 90%), but the pulsar's mass has not been assumed to be a certain value.
Our results are as follows. The companion star should be a MS. For the case
that the radius equals to its Roche one, we have a companion star with mass
and radius , and the
inclination angle is ; for the case that the radius
reaches 90% of its Roche one, we have , and . We also obtain the mass of J1749,
, and conclude that the pulsar could be a quark star
if the ratio of the critical frequency of rotation-mode instability to the
Keplerian one is higher than . The relatively low pulsar mass (about
) may also challenge the conventional recycling scenario for the
origin and evolution of millisecond pulsars. The results presented in this
paper are expected to be tested by future observations.Comment: RAA accepte
Photodissociation of p-process nuclei studied by bremsstrahlung induced activation
A research program has been started to study experimentally the
near-threshold photodissociation of nuclides in the chain of cosmic heavy
element production with bremsstrahlung from the ELBE accelerator. An important
prerequisite for such studies is good knowledge of the bremsstrahlung
distribution which was determined by measuring the photodissociation of the
deuteron and by comparison with model calculations. First data were obtained
for the astrophysically important target nucleus 92-Mo by observing the
radioactive decay of the nuclides produced by bremsstrahlung irradiation at
end-point energies between 11.8 MeV and 14.0 MeV. The results are compared to
recent statistical model calculations.Comment: 6 pages, 8 figures, Proceedings Nuclear Physics in Astrophysics II,
May 16-20, 2005, Debrecen, Hungary. The original publication is available at
www.eurphysj.or
On the Relation Between Hot Jupiters & the Roche Limit
Many of the known extrasolar planets are ``hot Jupiters,'' giant planets with
orbital periods of just a few days. We use the observed distribution of hot
Jupiters to constrain the location of its inner edge in the mass--period
diagram. If we assume a slope corresponding to the classical Roche limit, then
we find that the edge corresponds to a separation close to_twice_ the Roche
limit, as expected if the planets started on highly eccentric orbits that were
later circularized. In contrast, any migration scenario would predict an inner
edge right at the Roche limit, which applies to planets approaching on nearly
circular orbits. However, the current sample of hot Jupiters is not sufficient
to provide a precise constraint simultaneously on both the location and slope
of the inner edge.Comment: 10 pages, 3 figures, to appear in ApJ
Dretske on Self-Knowledge and Contrastive Focus: How to Understand Dretske’s Theory, and Why It Matters
Dretske’s theory of self-knowledge is interesting but peculiar and can seem implausible. He denies that we can know by introspection that we have thoughts, feelings, and experiences. But he allows that we can know by introspection what we think, feel, and experience. We consider two puzzles. The first puzzle, PUZZLE 1, is interpretive. Is there a way of understanding Dretske’s theory on which the knowledge affirmed by its positive side is different than the knowledge denied by its negative side? The second puzzle, PUZZLE 2, is substantive. Each of the following theses has some prima facie plausibility: there is introspective knowledge of thoughts, knowledge requires evidence, and there are no experiences of thoughts. It is unclear, though, that these claims form a consistent set. These puzzles are not unrelated. Dretske’s theory of self-knowledge is a potential solution to PUZZLE 2 in that Dretske’s theory is meant to show how,, and can all be true. We provide a solution to PUZZLE 1 by appeal to Dretske’s early work in the philosophy of language on contrastive focus. We then distinguish between “Closure” and “Transmissibility”, and raise and answer a worry to the effect that Dretske’s theory of self-knowledge runs counter to Transmissibility. These results help to secure Dretske’s theory as a viable solution to PUZZLE 2
The Roche problem: some analytics
Some exact analytical formulas are derived for the potential and mass ratio
as a function of Lagrangian points position, in the classical Roche model of
the close binary stars.Comment: aastex, 4 pp. ApJ accepte
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