Introduction to J. B. Erhard's 'Devil's Apology' (1795)

This is the introduction to “Johann Benjamin Erhard, ‘Devil’s Apology’(1795)”, translated by J. Clarke and C. Rhode, British Journal for the History of Philosophy, DOI: 10.1080/09608788.2018.1441805

Fichte, Hegel, and the Life and Death Struggle

Several commentators have argued that Hegel’s account of ‘self-consciousness’ in Chapter IV of the Phenomenology of Spirit can be read as an ‘immanent critique’ of Fichte’s idealism. If this is correct, it raises the question of whether Hegel’s account of ‘recognition’ in Chapter IV can be interpreted as a critique of Fichte’s conception of recognition as expounded in the Foundations of Natural Right. A satisfactory answer to this question will have to provide a plausible interpretation of the ‘life and death struggle’ as an immanent critique of Fichte’s account of recognition. This paper aims to provide such an interpretation. The first part of the paper provides a discussion of Fichte’s account of recognition that emphasizes its ‘epistemic’ concerns. The second part argues that Hegel’s account of the ‘life and death struggle’ can be read plausibly as a critique of Fichte’s account of recognition

Fichte's theory of Intersubjectivity

This thesis rejects the traditional picture of Fichte as a 'philosopher of subjectivity' who conceives of reality as the product of an 'absolute subject'. In opposition to this view, this thesis presents Fichte as a philosopher of intersubjectivity, whose primary concern is with relations between subjects. It argues that the true originality of Fichte's philosophy lies in his claim that intersubjectivity is a condition of the possibility of self- consciousness. Part 1 of this thesis defends Fichte's claim that Kant's transcendental idealism requires an account of how we recognize other rational beings. It seeks to demonstrate the necessity of such an account by examining the role of intersubjectivity within Kant's transcendental philosophy. Chapters 1, 2 and 3 deal, respectively, with the significance of intersubjectivity for Kant's accounts of theoretical reason, practical reason and the unity of reason. Part 2 of this thesis considers Fichte's attempt to develop a theory of intersubjectivity within his system of transcendental philosophy or Wissenschaftslehre. Chapter 4 considers Fichte's conception of such a system, and stresses the importance of political, ethical and pedagogical themes to this conception. Chapter 5 provides a detailed discussion of Fichte's first serious treatment of the topic of intersubjectivity — Some Lectures Concerning the Scholar's Vocation. Chapter 6 seeks to provide a reading of Fichte's first presentation of the 'foundations' of his system that is consistent with his concern with intersubjectivity. Chapters 7 provide an extensive discussion of Fichte's most complete presentation of his theory of intersubjectivity — the Foundations of Natural Right

Johann Benjamin Erhard, 'Devil's Apology' (1795)

This is a translation of J. B. Erhard's 1795 essay "Apologie des Teufels"

Experimental determination of the stable boundary for a cylindrical ion trap

The first radio frequency (rf) quadrupole ion traps were designed with hyperbolic trapping electrodes and had the advantage of a working theoretical model with an analytical solution for the equation of motion for an ion. This came at the cost of a difficult fabrication process by the nature of the hyperbolic design. Cylindrical designs were found to be an easily constructed and functional alternative for ion trapping, but a sound theoretical model for this geometry has yet to emerge. While the hyperbolic theory yields approximate parameters for stable ion trapping, experiments conducted near the stable/unstable boundary require an experimental determination of this boundary

The imprint of photoevaporation on edge-on discs

We have performed hydrodynamic and radiative transfer calculations of a photoevaporating disc around a Herbig Ae/Be star to determine the evolution and observational impact of dust entrained in the wind. We find that the wind selectively entrains grains of different sizes at different radii resulting in a dust population that varies spatially and increases with height above the disc at radii > 10 AU. This variable grain population results in a 'wingnut' morphology to the dust density distribution. We calculate images of this dust distribution at NIR wavelengths that also show a wingnut morphology at all wavelengths considered. We have also considered the contribution that crystalline dust grains will have in the wind and show that a photoevaporative wind can result in a significant crystallinity fraction at all radii, when the disc is edge-on. However, when the disc's photosphere is unobscured, a photoevaporative wind makes no contribution to the observable crystallinity fraction in the disc. Finally, we conclude that the analysis of extended emission around edge-on discs could provide a new and independent method of testing photoevaporation models.Comment: 8 pages, 6 figures, accepted for publication in MNRA

Public experiences of mass casualty decontamination

In this article, we analyze feedback from simulated casualties who took part in field exercises involving mass decontamination, to gain an understanding of how responder communication can affect people’s experiences of and compliance with decontamination. We analyzed questionnaire data gathered from 402 volunteers using the framework approach, to provide an insight into the public’s experiences of decontamination and how these experiences are shaped by the actions of emergency responders. Factors that affected casualties’ experiences of the econtamination process included the need for greater practical information and better communication from responders, and the need for privacy. Results support previous findings from small-scale incidents that involved decontamination in showing that participants wanted better communication from responders during the process of decontamination, including more practical information, and that the failure of responders to communicate effectively with members of the public led to anxiety about the decontamination process. The similarity between the findings from the exercises described in this article and previous research into real incidents involving decontamination suggests that field exercises provide a useful way to examine the effect of responder communication strategies on the public’s experiences of decontamination. Future exercises should examine in more detail the effect of various communication strategies on the public’s experiences of decontamination. This will facilitate the development of evidence-based communication strategies intended to reduce anxiety about decontamination and increase compliance among members of the public during real-life incidents that involve mass decontamination

Two populations of transition discs?

We examine the distribution of transition discs as a function of mm flux. We confirm that as expected in any model in which most primordial discs turn into transition discs and in which mm flux declines with time, transition discs have lower mm fluxes on average than primordial discs. However, we find that the incidence of transition discs does not, as expected, fall monotonically towards large mm fluxes and we investigate the hypothesis that these mm bright transition discs may have a distinct physical origin. We find that mm bright transition discs occupy a separate region of parameter space. Transition discs in the bright mm sub-sample have systematically higher accretion rates and inner hole radii than those in the faint mm sub-sample, along with being systematically weighted to earlier spectral types.Comment: 5 pages, 5 figures, accepted version: mnras letter

Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaportion

(Abridged) We explore the role of X-ray photoevaporation in the evolution and dispersal of viscously evolving T-Tauri discs. We show that the X-ray photoevaporation wind rates scale linearly with X-ray luminosity, such that the observed range of X-ray luminosities for solar-type T-Tauri stars (10e28-10e31 erg\s) gives rise to vigorous disc winds with rates of order 10e-10-10e-7 M_sun/yr. We use the wind solutions from radiation-hydrodynamic models, coupled to a viscous evolution model to construct a population synthesis model so that we may study the physical properties of evolving discs and so-called `transition discs'. Current observations of disc lifetimes and accretion rates can be matched by our model assuming a viscosity parameter alpha = 2.5e-3. Our models confirm that X-rays play a dominant role in the evolution and dispersal of protoplanetary discs giving rise to the observed diverse population of inner hole `transition' sources which include those with massive outer discs, those with gas in their inner holes and those with detectable accretion signatures. To help understand the nature of observed transition discs we present a diagnostic diagram based on accretion rates versus inner hole sizes that demonstrate that, contrary to recent claims, many of the observed accreting and non accreting transition discs can easily be explained by X-ray photoevaporation. Finally, we confirm the conjecture of Drake et al. (2009), that accretion is suppressed by the X-rays through `photoevaporation starved accretion' and predict this effect can give rise to a negative correlation between X-ray luminosity and accretion rate, as reported in the Orion data.Comment: Figure 12 and 13 have been updated. In the original version the results from an unused model run were plotted by mistak

Theoretical spectra of photoevaporating protoplanetary discs: An atlas of atomic and low-ionisation emission lines

We present a calculation of the atomic and low-ionisation emission line spectra of photoevaporating protoplanetary discs. Line luminosities and profiles are obtained from detailed photoionisation calculations of the disc and wind structures surrounding young active solar-type stars. The disc and wind density and velocity fields were obtained from the recently developed radiation-hydrodynamic models of Owen et al., that include stellar X-ray and EUV irradiation of protoplanetary discs at various stages of clearing, from primordial sources to inner hole sources of various hole sizes. Our models compare favourably with currently available observations, lending support to an X-ray driven photoevaporation model for disc dispersal. In particular, we find that X-rays drive a warm, predominantly neutral flow where the OI 6300A line can be produced by neutral hydrogen collisional excitation. Our models can, for the first time, provide a very good match to both luminosities and profiles of the low-velocity component of the OI 6300A line and other forbidden lines observed by Hartigan et al., which covered a large sample of T-Tauri stars. We find that the OI 6300A and the NeII 12.8um lines are predominantly produced in the X-ray-driven wind and thus appear blue-shifted by a few km/s for some of the systems when observed at non-edge-on inclinations. We note however that blue-shifts are only produced under certain conditions: X-ray luminosity, spectral shape and inner hole size all affect the location of the emitting region and the physical conditions in the wind. We caution therefore that while a blueshifted line is a tell-tale sign of an outflow, the lack of a blueshift should not be necessarily interpreted as a lack of outflow.Comment: 18 pages, 7 figures, accepted to be published in MNRAS - changes in the revised version: reference list update