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According to his own understanding, Jürgen Habermas’ Theory of Communicative Action offers a new account of the normative foundations of critical theory. 1 Habermas’ motivating insight is that neither a transcendental or metaphysical solution to the problem of normativity, nor a merely hermeneutic reconstruction of historically given norms, is sufficient to clarify the normative foundations of critical theory. In response to this insight, Habermas develops a novel account of normativity which locates the normative demands upon which critical theory draws within the socially instituted practice of communicative understanding. Although Habermas has claimed otherwise, this new foundation for critical theory constitutes a novel and innovative form of “immanent critique”. To argue for and to clarify this claim, I offer, in section 1, a formal account of immanent critique and distinguish between two different ways of carrying out such a critique. In section 2, I examine Habermas’ rejection of the first, hermeneutic option. Against this background, I then show, in section 3, that the Theory of Communicative Action attempts to formulate an immanent critique of contemporary societies according to a second, “practice-based” model. However, because Habermas, as I will argue in section 4, commits himself to an implausibly narrow view in regard to one central element of such a model – in regard to the social ontology of immanent normativity – his normative critique cannot develop its full potential (section 5).
Ist die Literatur, als Abweichung oder als Erfüllung der Ausdrucksfunktion der Sprache verstanden, eine Diskursform, die dem Bereich der Wahrheit zugänglich ist, oder aber verhindert sie jeden systematischen Zugang zur Wahrheit? Und was ist überhaupt damit gewonnen, wenn Literatur und Wahrheit in einen Zusammenhang zueinander gesetzt werden? Diese Fragen mit einer neuen Dringlichkeit versehen zu haben, die über den Gegensatz von analytischer Philosophie und Dekonstruktion hinausreicht, ist das Verdienst der Arbeiten von Stanley Cavell. Im Folgenden geht es darum, die Frage nach der Wahrheit in der Literatur noch einmal anhand der Auseinandersetzung mit Cavells Schriften stellen, um die Reichweite wie die Grenzen des philosophischen Diskurses über die Literatur zu bestimmen. [...] Was für Cavell in grundsätzlicher Weise in Frage steht, ist zum einen das Wissen, das die Philosophie von der Welt haben kann und zum anderen das Wissen, was Philosophie und Literatur in ihrer gemeinsamen und doch unterschiedlichen Auseinandersetzung mit dem Skeptizismus voneinander haben können. In dem Maße, in dem er nach den Möglichkeiten einer Überwindung des Skeptizismus sucht, erkennt Cavell zunächst spezifische Formen des Nichtwissens an, die er im Kontext philosophischer wie literarischer Texte gleichermaßen thematisiert. Eine besondere Stellung nimmt in diesem Zusammenhang der wiederholte Rückgriff auf Shakespeare ein, der in "Der Anspruch der Vernunft" in einer Lektüre des "Othello" kulminiert, die anhand der Analyse der Tragödie als Ausdruck von und Antwort an den Skeptizismus das Problem von Wissen und Nichtwissen zu fassen erlaubt. Insofern bietet es sich an, Cavells Überlegungen zum Zusammenhang von Tragödie und Skeptizismus einer kritischen Lektüre zu unterziehen, die im Rahmen seiner eigenen Fragestellung noch einmal nach dem grundsätzlichen Verhältnis von Literatur und philosophischer Wahrheitsfindung fragt.
Cognition requires the dynamic modulation of effective connectivity, i.e. the modulation of the postsynaptic neuronal response to a given input. If postsynaptic neurons are rhythmically active, this might entail rhythmic gain modulation, such that inputs synchronized to phases of high gain benefit from enhanced effective connectivity. We show that visually induced gamma-band activity in awake macaque area V4 rhythmically modulates responses to unpredictable stimulus events. This modulation exceeded a simple additive superposition of a constant response onto ongoing gamma-rhythmic firing, demonstrating the modulation of multiplicative gain. Gamma phases leading to strongest neuronal responses also led to shortest behavioral reaction times, suggesting functional relevance of the effect. Furthermore, we find that constant optogenetic stimulation of anesthetized cat area 21a produces gamma-band activity entailing a similar gain modulation. As the gamma rhythm in area 21a did not spread backwards to area 17, this suggests that postsynaptic gamma is sufficient for gain modulation.
In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this article, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity \Delta\eta and azimuthal angle \Delta\phi in Pb-Pb collisions at sqrt{s_{NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in \Delta\phi but fails to describe the correlations in \Delta\eta. A thermal blast wave model incorporating local charge conservation and tuned to describe the p_T spectra and v_2 measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sqrt{s_{NN}}: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in \Delta\eta and \Delta\phi with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.
In diesem Beitrag werden Ansätze zur Förderung der Eignungsreflexion der Studierenden im Lehramt sowie der Beratungskompetenz der betreuenden Lehrenden an der Goethe-Universität Frankfurt dargestellt: Für die Studierenden wurden unterschiedliche Maßnahmen entwickelt und implementiert, die die Reflexion über die persönliche Eignung für den Lehrerberuf fördern und bestehende Defizite frühzeitig ausgleichen helfen. Für die betreuenden Lehrenden (an Universität und Schule) wurde eine hochschuldidaktische Weiterbildung entwickelt und eingesetzt, welche deren Beratungskompetenz stärken soll.
Die Bedeutung des philosophischen Programms John McDowells, das schon in der theoretischen Philosophie eine revolutionäre Neuausrichtung vornimmt, kann erst voll erkannt werden, wenn man auch seine Konsequenzen für die praktische Philosophie in den Blick nimmt. Zwar geht Geist und Welt primär von Dilemmata der Erkenntnistheorie aus. Aus McDowells Vorschlag, die Gleichsetzung der äußeren Natur mit dem bedeutungsfreien Raum der Naturgesetze zugunsten einer Konzeption von Gründen in der Welt aufzugeben, ergibt sich aber die Möglichkeit einer so neuartigen Perspektive auf die Natur moralischer Urteile, dass es fast so scheint, als sei McDowells theoretisches Programm auf diesen Gewinn für die praktische Philosophie hin angelegt worden.
In this special issue of Matrix Biology centered on proteoglycan biology we have assembled a blend of articles focused on the state-of-the-art of proteoglycanology. The field has greatly expanded in the past three decades and now encompasses all the areas of biology. This special issue is divided into five chapters describing hyaluronan metabolism, biosynthetic and catabolic pathways of proteoglycans and their roles in inflammation, cancer, repair and development. We hope that the new original work and the reviews from recognized leaders will stimulate investigations in this exciting and fertile field of research.
Cross-frequency coupling (CFC) has been proposed to coordinate neural dynamics across spatial and temporal scales. Despite its potential relevance for understanding healthy and pathological brain function, the standard CFC analysis and physiological interpretation come with fundamental problems. For example, apparent CFC can appear because of spectral correlations due to common non-stationarities that may arise in the total absence of interactions between neural frequency components. To provide a road map towards an improved mechanistic understanding of CFC, we organize the available and potential novel statistical/modeling approaches according to their biophysical interpretability. While we do not provide solutions for all the problems described, we provide a list of practical recommendations to avoid common errors and to enhance the interpretability of CFC analysis.
Abstract Trial-to-trial variability and spontaneous activity of cortical recordings have been suggested to reflect intrinsic noise. This view is currently challenged by mounting evidence for structure in these phenomena: Trial-to-trial variability decreases following stimulus onset and can be predicted by previous spontaneous activity. This spontaneous activity is similar in magnitude and structure to evoked activity and can predict decisions. Allof the observed neuronal properties described above can be accounted for, at an abstract computational level, by the sampling-hypothesis, according to which response variability reflects stimulus uncertainty. However, a mechanistic explanation at the level of neural circuit dynamics is still missing.
In this study, we demonstrate that all of these phenomena can be accounted for by a noise-free self-organizing recurrent neural network model (SORN). It combines spike-timing dependent plasticity (STDP) and homeostatic mechanisms in a deterministic network of excitatory and inhibitory McCulloch-Pitts neurons. The network self-organizes to spatio-temporally varying input sequences.
We find that the key properties of neural variability mentioned above develop in this model as the network learns to perform sampling-like inference. Importantly, the model shows high trial-to-trial variability although it is fully deterministic. This suggests that the trial-to-trial variability in neural recordings may not reflect intrinsic noise. Rather, it may reflect a deterministic approximation of sampling-like learning and inference. The simplicity of the model suggests that these correlates of the sampling theory are canonical properties of recurrent networks that learn with a combination of STDP and homeostatic plasticity mechanisms.
Author Summary Neural recordings seem very noisy. If the exact same stimulus is shown to an animal multiple times, the neural response will vary. In fact, the activity of a single neuron shows many features of a stochastic process. Furthermore, in the absence of a sensory stimulus, cortical spontaneous activity has a magnitude comparable to the activity observed during stimulus presentation. These findings have led to a widespread belief that neural activity is indeed very noisy. However, recent evidence indicates that individual neurons can operate very reliably and that the spontaneous activity in the brain is highly structured, suggesting that much of the noise may in fact be signal. One hypothesis regarding this putative signal is that it reflects a form of probabilistic inference through sampling. Here we show that the key features of neural variability can be accounted for in a completely deterministic network model through self-organization. As the network learns a model of its sensory inputs, the deterministic dynamics give rise to sampling-like inference. Our findings show that the notorious variability in neural recordings does not need to be seen as evidence for a noisy brain. Instead it may reflect sampling-like inference emerging from a self-organized learning process.
The ALICE collaboration at the LHC reports measurement of the inclusive production cross section of electrons from semi-leptonic decays of beauty hadrons with rapidity |y|<0.8 and transverse momentum 1<pT<10 GeV/c, in pp collisions at s√= 2.76 TeV. Electrons not originating from semi-electronic decay of beauty hadrons are suppressed using the impact parameter of the corresponding tracks. The production cross section of beauty decay electrons is compared to the result obtained with an alternative method which uses the distribution of the azimuthal angle between heavy-flavour decay electrons and charged hadrons. Perturbative QCD calculations agree with the measured cross section within the experimental and theoretical uncertainties. The integrated visible cross section, σb→e=3.47±0.40(stat)+1.12−1.33(sys)±0.07(norm)μb, was extrapolated to full phase space using Fixed Order plus Next-to-Leading Log (FONLL) predictions to obtain the total bb¯ production cross section, σbb¯=130±15.1(stat)+42.1−49.8(sys)+3.4−3.1(extr)±2.5(norm)±4.4(BR)μb.