We model the stochastic evolution of the probability density functions (PDFs) of Ibovespa intraday returns over business days, in a functional time series framework. We find evidence that the dynamic structure of the PDFs reduces to a vector process lying in a two-dimensional space. Our main contributions are as follows. First, we provide further insights into the finite-dimensional decomposition of the curve process: it is shown that its evolution can be interpreted as a dynamic dispersion-symmetry shift. Second, we provide an application to realized volatility forecasting, with a forecasting ability that is comparable to those of HAR realized volatility models in the model confidence set framework.

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Neste artigo, articulo e critico os dois principais argumentos apresentados por Clifford em favor da norma de que é ilegítimo crer com base em evidência insuficiente. O primeiro argumento apela para o valor instrumental da crença, e o segundo apela para o nosso interesse intrínseco na verdade. Ambos os argumentos trazem à tona a relevância de fatores morais e sociais para a determinação de normas da crença. Eu sustento que o primeiro argumento é insuficiente para estabelecer a norma de Clifford em geral. Crenças que não são meios para ações ficam de fora do escopo do primeiro argumento. O segundo argumento tem um alcance mais abrangente. Contudo, ele pode ser bloqueado se o agente segue uma norma intelectualista que visa insular as crenças injustificadas do restante da sua vida cognitiva e ativa. É uma questão empírica se agentes humanos são capazes de seguir essa norma. Defendo uma reformulação da norma de Clifford, incluindo alguns parâmetros que influenciam a suficiência dos indícios. Por fim, fatores morais ou prudenciais podem afetar a legitimidade da crença. É legítimo crer sem indícios suficientes apenas em casos especiais, quando o agente insula a crença injustificada, ou quando o bem que advém da crença sobrepuja os malefícios da credulidade.

In Fact, Fiction and Forecast, Nelson Goodman claims that the problem of justifying induction is not something over and above the problem of describing valid induction. Such claim seems to open up the possibility that the new riddle of induction could be addressed empirically. Discoveries about psychological preferences for projecting certain classes of objects could function as a criterion for determining which predicates are after all projectible. In this paper, I argue that Goodman's claim must be construed within his project for constructional definitions, which is methodologically oriented by reflective equilibrium. The description of inductive practice is committed to the articulation of the extension of the class selected by the predicate ‘valid induction’. The mutual adjustment between theoretical considerations and inductive practice involved in the proposal of a definition of ‘valid induction’ must preserve that practice as much as possible, there is no way to get rid of entrenchment. Empirical discoveries about the psychological mechanism that underlies projections may help that adjustment but they cannot substitute the role played by the entrenchment of predicates.

Versão a convite de um artigo homônimo para o italiano.

In 1995 the publication of Marleen Rozemond’s paper Descartes’s Case for Dualism has triggered the revival of the discussion on his argument in favor of the real distinction between body and soul among the Anglo-Saxon scholars. In particular the discussion then resumed was on the necessity of introducing a hidden premise (the so called the attribute premise) in order to regain its probatory character. This debate has reflected on the Cartesian studies in Brazil and my objective in this text is to bring to the debate two texts still unexplored related to this interpretative problem. My hypothesis is that the attempts to justify the thesis that the substance has exactly one principal attribute have not yet better succeeded because they underestimated the contribution brought about by the transformation of the notion of nature entailed by the introduction of the concept of principal attribute. Understanding the Cartesian proof of substantial dualism, and more particularly the “attribute premise”, would involve, I suggest, the thesis according to which the concept of principal attribute, insofar as it expresses the essence of the substance, is not – and cannot be – according to Descartes, an abstract universal, but rather a particular nature