Realism, Objectivity, and Evaluation

I discuss Benacerraf's epistemological challenge for realism about areas like mathematics, metalogic, and modality, and describe the pluralist response to it. I explain why normative pluralism is peculiarly unsatisfactory, and use this explanation to formulate a radicalization of Moore's Open Question Argument. According to the argument, the facts -- even the normative facts -- fail to settle the practical questions at the center of our normative lives. One lesson is that the concepts of realism and objectivity, which are widely identified, are actually in tension

Combined Weekly Coordinate Solutions from SLR and DORIS

In International Terrestrial Reference Frame (ITRF) 2005 and ITRF2008, the approach for the construction of solutions by the IERS has been for individual analysis centers of each technique to process geodetic tracking data, and for each technique to develop a solution (or contribution) that is integrated into the final ITRF solution by careful combination of the technique solutions. The connections between the geodetic networks are realized by the application of local ties. In an alternate approach, we may assure processing homogeneity by creating normal equations for different techniques with the same orbit determination software, using identically derived algorithms. Another derivative of this approach is to realize the ties between the techniques using satellites tracked with multiple techniques; in effect tieing the networks together using satellite dynamics. In this solution, we develop a time series and a set of cumulative solutions from Satellite Laser Ranging (SLR) & Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS) based on homogeneous processing with the NASA GEODYN precise orbit determination suite of programs, where we jointly combine weekly the SLR data to Lageos1, Lageos2, Starlette, and Stella with the DORIS data from SPOT2-SPOT5, as well as satellites that utilize both techniques (TOPEX/Poseidon, Envisat, Jason-2). We discuss the modeling that is applied including upgrades implemented since the submission of the GSC ITRF2008 contributions for IDS. Firstly, we compare the SLR-only solutions comprising four geodetic satellites with the standard approach of utilizing only Lageos1 & Lageos2. Secondly, we evaluate the impact on the DORIS coordinates of the joint analysis with the SLR data

Stronger Than Yesterday: Investigating Peoples’ Experiences of View Strengthening on Social Media

Polarization of views (known as ideological polarization) is one of the greatest societal challenges of our time, potentially sewing distrust and hate among individuals and communities and threatening to undermine the fabric of democracy. Divisive issues such as abortion and gun control are ever-present and can drive issue polarization, and even affective polarization—a disdain for ‘the other side,’ which can further divide society. Social media has been flagged as a breeding ground for polarized views, with private groups and personalized algorithms facilitating selfcreation of echo chambers that may lead to polarization. While there is prior research on the technological influences on view strengthening, scant Human-centered research exists and most of it has focused on view change in general, rather than view strengthening specifically. To investigate peoples’ experiences of view strengthening on social media, we interviewed 10 people who recently strengthened their views on important topics. While some took steps to avoid creating echo chambers (e.g., by seeking out opposing views), others intentionally created them to allow their views to strengthen without interference. These findings have important implications for designing social media platforms that support careful and conscious view strengthening while mitigating against the risk of information manipulation

Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

Several works analyzing the new physics contributions from the Left-Right Symmetric Model to the CP violation phenomena in the neutral B mesons can be found in the literature. These works exhibit interesting and experimentally sensible deviations from the Standard Model predictions but at the expense of considering a low right scale \upsilon_R around 1 TeV. However, when we stick to the more conservative estimates for \upsilon_R which say that it must be at least 10^7 GeV, no experimentally sensible deviations from the Standard Model appear for indirect CP violation. This estimate for \upsilon_R arises when the generation of neutrino masses is considered. In spite of the fact that this scenario is much less interesting and says nothing new about both the CP violation phenomenon and the structure of the Left-Right Symmetric Model, this possibility must be taken into account for the sake of completeness and when considering the see-saw mechanism that provides masses to the neutrino sector.Comment: LaTex file. 19 pages, 4 figures. Change in the way the paper address the problem. As a result, change in title, abstract, and some sections. Conclusions unchanged. Version to appear in Foundations of Physics Letter

On the Hadronic Beam Model for Gamma-ray Production in Blazars

We consider, herein, a model for gamma-ray production in blazars in which a relativistic, highly-collimated electron-proton beam interacts with a dense, compact cloud as the jet propagates through the broad and perhaps narrow line regions (BLR and NLR) of active galactic nuclei (AGN). During the propagation of the beam through the cloud, the process of excitation of plasma waves becomes an important energy loss mechanism, especially for mildly relativistic proton beams. We compute the expected spectra of gamma-rays from the decay of neutral pions produced in hadronic collisions of the beam with the cloud, taking into account collisionless losses of the electron-proton beam. This model may explain the X-ray and TeV gamma-ray (both low and high emission states) of Mrk 421 as a result of synchrotron emission of secondary pairs from the decay of charged pions and gamma-ray emission from the decay of neutral pions for the plausible cloud parameters. However clouds can not be too hot and too dense. Otherwise the TeV gamma-rays can be attenuated by the bremsstrahlung radiation in the cloud and the secondary pairs are not able to efficiently produce synchrotron flares because of the dominant role of inverse Compton scattering. The non-variable $\gamma$-ray emission observed from Mrk 421 in the EGRET energy range cannot be described by the $\gamma$-rays from decay of neutral pions provided that the spectrum of protons in the beam is well described by a simple power law. These $\gamma$-rays might only be produced by secondary pairs scattering the soft non-variable X-rays which might originate in the inner part of the accretion disk.Comment: 14 pages,3 figures, latex, submitted to Ap