Complex SUSY Transformations and the Painlev\'e IV Equation

In this paper we will explicitly work out the complex first-order SUSY transformation for the harmonic oscillator in order to obtain both real and complex new exactly-solvable potentials. Furthermore, we will show that this systems lead us to exact complex solutions of the Painlev\'e IV equation with complex parameters. We present some concrete examples of such solutions

Truth and falsehood for non-representationalists: Gorgias on the normativity of language

Sophists and rhetoricians like Gorgias are often accused of disregarding truth and rationality: their speeches seem to aim only at effective persuasion, and be constrained by nothing but persuasiveness itself. In his extant texts Gorgias claims that language does not represent external objects or communicate internal states, but merely generates behavioural responses in people. It has been argued that this perspective erodes the possibility of rationally assessing speeches by making persuasiveness the only norm, and persuasive power the only virtue, of speech. Against this view, I show how Gorgias’ texts support a robust normativity of language that goes well beyond persuasion while remaining non-representational. Gorgias’ claims that a speech can be persuasive and false, or true and unpersuasive, reveal pragmatic, epistemic, and agonistic constraints on the validity of speech that are neither representational nor reducible to sheer persuasiveness

Can reason establish the goals of action? Assessing interpretations of Aristotle’s theory of agency

Scholarship on Aristotle’s theory of action has recently veered toward an intellectualist position, according to which reason is in charge of setting the goals of action. This position has recently been criticized by an anti-intellectualism revival, according to which character, and not reason, sets the goals of action. I argue that neither view can sufficiently account for the complexities of Aristotle’s theory, and suggest a middle way that combines the strengths of both while avoiding their pitfalls. The key problem for intellectualism is that Aristotle explicitly states reason cannot set the goals of action. The key problem for anti-intellectualism is that he also holds that the soul’s rational part must guide and prescribe over the non-rational part. I propose indirect intellectualism, a promising middle path

Social media and self-control: The vices and virtues of attention

Self-control, the capacity to resist temptations and pursue longer-term goals over immediate gratifications, is crucial in determining the overall shape of our lives, and thereby in our ability to shape our identities. As it turns out, this capacity is intimately linked with our ability to control the direction of our attention. This raises the worry that perhaps social media are making us more easily distracted people, and therefore less able to exercise self-control. Is this so? And is it necessarily a bad thing? This paper analyzes the nature of attention, its vices and virtues, and what currently available evidence has to say about the effects of social media on attention and self-control. The pattern that seems to be emerging is that, although there is an association between higher use of social media and lower attentional control, we do not yet know whether it is social media use that makes people more distracted, or whether those who use social media the most do so because they are more easily distracted. Either way, the rise of the ‘Web 2.0’ does raise questions about whether the virtues of attention will change in the future, and whether this will bring with it a transformation in the way we shape our selves

Nonconceptual content and the nature of perceptual experience

Recent philosophy of mind and epistemology has seen an important and influential trend towards accounting for at least some features of experiences in content-involving terms. It is a contested point whether ascribing content to experiences can account for all the intrinsic properties of experiences, but on many theories of experiences there are close links between the ascription of content and the ways in which experiences are ascribed and typed. The issues here have both epistemological and psychological dimensions. On the one hand, a theory of experiential content has a fundamental role in explaining how knowledge of the world can be acquired through experience. On the other hand, there are important psychological questions about the phenomenology of experiences and the conditions under which content ascriptions are made. The debate about whether experiences have conceptual or nonconceptual content is highly relevant to both the epistemological and psychological issues. This is apparent in the work of Gareth Evans who is often cited as the first philosopher to propose a theory of nonconceptual content. This paper will explicate and examine Evans' theory. In particular, attention will be paid to Evans' claim that perceptually-derived information with nonconceptual content can only qualify as a perceptual experience when it serves as input to a thinking, concept-applying, and reasoning system. We will sketch out a theoretical approach to the nature of nonconceptual content that builds on Evans' insight but does not follow him in this restrictive claim

The twilight zone in the parametric evolution of eigenstates: beyond perturbation theory and semiclassics

Considering a quantized chaotic system, we analyze the evolution of its eigenstates as a result of varying a control parameter. As the induced perturbation becomes larger, there is a crossover from a perturbative to a non-perturbative regime, which is reflected in the structural changes of the local density of states. For the first time the {\em full} scenario is explored for a physical system: an Aharonov-Bohm cylindrical billiard. As we vary the magnetic flux, we discover an intermediate twilight regime where perturbative and semiclassical features co-exist. This is in contrast with the {\em simple} crossover from a Lorentzian to a semicircle line-shape which is found in random-matrix models.Comment: 4 pages, 4 figures, improved versio

Mixture of bivariate Poisson regression models with an application to insurance

In a recent paper Bermúdez [2009] used bivariate Poisson regression models for ratemaking in car insurance, and included zero-inflated models to account for the excess of zeros and the overdispersion in the data set. In the present paper, we revisit this model in order to consider alternatives. We propose a 2-finite mixture of bivariate Poisson regression models to demonstrate that the overdispersion in the data requires more structure if it is to be taken into account, and that a simple zero-inflated bivariate Poisson model does not suffice. At the same time, we show that a finite mixture of bivariate Poisson regression models embraces zero-inflated bivariate Poisson regression models as a special case. Additionally, we describe a model in which the mixing proportions are dependent on covariates when modelling the way in which each individual belongs to a separate cluster. Finally, an EM algorithm is provided in order to ensure the models’ ease-of-fit. These models are applied to the same automobile insurance claims data set as used in Bermúdez [2009] and it is shown that the modelling of the data set can be improved considerably.Zero-inflation, Overdispersion, EM algorithm, Automobile insurance, A priori ratemaking.

Remembering as a mental action

Many philosophers consider that memory is just a passive information retention and retrieval capacity. Some information and experiences are encoded, stored, and subsequently retrieved in a passive way, without any control or intervention on the subject’s part. In this paper, we will defend an active account of memory according to which remembering is a mental action and not merely a passive mental event. According to the reconstructive account, memory is an imaginative reconstruction of past experience. A key feature of the reconstructive account is that given the imperfect character of memory outputs, some kind of control is needed. Metacognition is the control of mental processes and dispositions. Drawing from recent work on the normativity of automaticity and automatic control, we distinguish two kinds of metacognitive control: top-down, reflective control, on the one hand, and automatic, intuitive, feeling-based control on the other. Thus, we propose that whenever the mental process of remembering is controlled by means of intuitive or feeling-based metacognitive processes, it is an action

A priori ratemaking using bivariate poisson regression models

In automobile insurance, it is useful to achieve a priori ratemaking by resorting to generalized linear models, and here the Poisson regression model constitutes the most widely accepted basis. However, insurance companies distinguish between claims with or without bodily injuries, or claims with full or partial liability of the insured driver. This paper examines an a priori ratemaking procedure when including two di®erent types of claim. When assuming independence between claim types, the premium can be obtained by summing the premiums for each type of guarantee and is dependent on the rating factors chosen. If the independence assumption is relaxed, then it is unclear as to how the tariff system might be affected. In order to answer this question, bivariate Poisson regression models, suitable for paired count data exhibiting correlation, are introduced. It is shown that the usual independence assumption is unrealistic here. These models are applied to an automobile insurance claims database containing 80,994 contracts belonging to a Spanish insurance company. Finally, the consequences for pure and loaded premiums when the independence assumption is relaxed by using a bivariate Poisson regression model are analysed.