Boghossian's template and transmission failure

Within his overarching program aiming to defend an epistemic conception of analyticity, Boghossian (1996 and 1997) has offered a clear-cut explanation of how we can acquire a priori knowledge of logical truths and logical rules through implicit definition. The explanation is based on a special template or general form of argument. Ebert (2005) has argued that an enhanced version of this template is flawed because a segment of it is unable to transmit warrant from its premises to the conclusion. This article aims to defend the template from this objection. We provide an accurate description of the type of non-transmissivity that Ebert attributes to the template and clarify why this is a novel type of non-transmissivity. Then, we argue that Jenkins (2008)’s response to Ebert fails because it focuses on doxastic rather than propositional warrant. Finally, we rebut Ebert’s objection on Boghossian’s behalf by showing that it rests on an unwarranted assumption and is internally incoherent

Assessing concept possession as an explicit and social practice

We focus on issues of learning assessment from the point of view of an investigation of philosophical elements in teaching. We contend that assessment of concept possession at school based on ordinary multiple-choice tests might be ineffective because it overlooks aspects of human rationality illuminated by Robert Brandom’s inferentialism––the view that conceptual content largely coincides with the inferential role of linguistic expressions used in public discourse. More particularly, we argue that multiple-choice tests at schools might fail to accurately assess the possession of a concept or the lack of it, for they only check the written outputs of the pupils who take them, without detecting the inferences actually endorsed or used by them. We suggest that school tests would acquire reliability if they enabled pupils to make the reasons of their answers or the inferences they use explicit, so as to contribute to what Brandom calls the game of giving and asking for reasons. We explore the possibility to put this suggestion into practice by deploying two-tier multiple-choice tests

Goldman and Siegel on the epistemic aims of education

Philosophers have claimed that education aims at fostering disparate epistemic goals. In this paper we focus on an important segment of this debate involving conversation between Alvin Goldman and Harvey Siegel. Goldman claims that education is essentially aimed at producing true beliefs. Siegel contends that education is essentially aimed at fostering both true beliefs and, independently, critical thinking and rational belief. Although we find Siegel’s position intuitively more plausible than Goldman’s, we also find Siegel’s defence of it wanting. We suggest novel argumentative strategies that draw on Siegel’s own arguments but look to us more promising

Ebert on Boghossian’s template and transmission failure

Boghossian (1996) has put forward an interesting explanation of how we can acquire logical knowledge via implicit definitions that makes use of a special template. Ebert (2005) has argued that the template is unserviceable, as it doesn't transmit warrant. In this paper, we defend the template. We first suggest that Jenkins (2008)’s response to Ebert fails because it focuses on doxastic rather than propositional warrant. We then reject Ebert’s objection by showing that it depends on an implausible and incoherent assumption

Assessing Concept Possession as an Explicit and Social Practice

We are grateful to Jan Derry, Fed Luzzi, Paul Standish, Shone Surendran, the audience of a research seminar of the Institute of Education of UCL, and two anonymous reviewers of this journal for comments on a draft of this paper.Peer reviewedPostprin

VLT spectroscopy of globular clusters in the Sombrero galaxy

We have obtained intermediate-resolution VLT spectroscopy of 75 globular cluster candidates around the Sa galaxy M104 (NGC4594). Fifty-seven candidates out to ~ 40 kpc in the halo of the galaxy were confirmed to be bona-fide globular clusters, 27 of which are new. A first analysis of the velocities provides only marginal evidence for rotation of the cluster system. From Hbeta line strengths, almost all of the clusters in our sample have ages that are consistent, within the errors, with Milky Way globular clusters. Only a few clusters may be 1-2 Gyr old, and bulge and halo clusters appear coeval. The absorption line indices follow the correlations established for the Milky Way clusters. Metallicities are derived based upon new empirical calibrations with Galactic globular clusters taking into account the non-linear behavior of some indices (e.g., Mg2). Our sample of globular clusters in NGC4594 spans a metallicity range of -2.13 < [Fe/H] < +0.26 dex, and the median metallicity of the system is [Fe/H] = -0.85. Thus, our data provide evidence that some of the clusters have super-solar metallicity. Overall, the abundance distribution of the cluster system is consistent with a bimodal distribution with peaks at [Fe/H] ~- 1.7 and -0.7. However, the radial change in the metallicity distribution of clusters may not be straightforwardly explained by a varying mixture of two sub-populations of red and blue clusters.Comment: 6 pages (incl. 4 figures) to appear in the proceedings of the ESO workshop "Extragalactic Globular Cluster Systems", ESO Astrophysics Symp., Garching bei Muenchen (Germany), ed. Kissler-Patig M., Springer-Verlag: Heidelber

From blue star-forming to red passive: galaxies in transition in different environments

Exploiting a mass complete (M_*>10^(10.25)M_sun) sample at 0.03<z<0.11 drawn from the Padova Millennium Galaxy Group Catalog (PM2GC), we use the (U-B)_rf color and morphologies to characterize galaxies, in particular those that show signs of an ongoing or recent transformation of their star formation activity and/or morphology - green galaxies, red passive late types, and blue star-forming early types. Color fractions depend on mass and only for M_*<10^(10.7)M_sun on environment. The incidence of red galaxies increases with increasing mass, and, for M_*<10^(10.7)M_sun, decreases toward the group outskirts and in binary and single galaxies. The relative abundance of green and blue galaxies is independent of environment, and increases monotonically with galaxy mass. We also inspect galaxy structural parameters, star-formation properties, histories and ages and propose an evolutionary scenario for the different subpopulations. Color transformations are due to a reduction and suppression of SFR in both bulges and disks which does not noticeably affect galaxy structure. Morphological transitions are linked to an enhanced bulge-to-disk ratio due to the removal of the disk, not to an increase of the bulge. Our modeling suggests that green colors might be due to star formation histories declining with long timescales, as an alternative scenario to the classical "quenching" processes. Our results suggest that galaxy transformations in star formation activity and morphology depend neither on environment nor on being a satellite or the most massive galaxy of a halo. The only environmental dependence we find is the higher fast quenching efficiency in groups giving origin to post-starburst signatures.Comment: 20 pages, 12 figures, accepted for publication in Ap

An update of the on-sky performance of the Layer-Oriented wave-front sensor for MAD

The Multi-conjugate Adaptive optics Demonstrator, MAD, successfully demonstrated on sky the MCAO technique both in Layer Oriented and Star Oriented modes. As results of the Guaranteed Time Observations in Layer Oriented mode quality astronomy papers have been published. In this paper we concentrate on the instrumentation issues and technical aspects which stay behind this success.Comment: 12 pages, 10 figures, Proceedings of the SPIE conference "Adaptive Optics Systems II", 27 June 2010, San Diego, California, US

The star formation history of galaxies: the role of galaxy mass, morphology and environment

We analyze the star formation history (SFH) of galaxies as a function of present-day environment, galaxy stellar mass and morphology. The SFH is derived by means of a non-parametric spectrophotometric model applied to individual galaxies at z ~ 0.04- 0.1 in the WINGS clusters and the PM2GC field. The field reconstructed evolution of the star formation rate density (SFRD) follows the values observed at each redshift (Madau & Dickinson 2014), except at z > 2 where our estimate is ~ 1.7x higher than the high-z observed value. The slope of the SFRD decline with time gets progressively steeper going from low mass to high mass haloes. The decrease of the SFRD since z = 2 is due to 1) quenching - 50% of the SFRD in the field and 75% in clusters at z > 2 originated in galaxies that are passive today - and 2) the fact that the average SFR of today's star-forming galaxies has decreased with time. We quantify the contribution to the SFRD(z) of galaxies of today's different masses and morphologies. The current morphology correlates with the current star formation activity but is irrelevant for the past stellar history. The average SFH depends on galaxy mass, but galaxies of a given mass have different histories depending on their environment. We conclude that the variation of the SFRD(z) with environment is not driven by different distributions of galaxy masses and morphologies in clusters and field, and must be due to an accelerated formation in high mass haloes compared to low mass ones even for galaxies that will end up having the same galaxy mass today.Comment: 16 pages, 10 figures. Published on MNRA