Coherence & Confirmation: The Epistemic Limitations of the Impossibility Theorems

It is a widespread intuition that the coherence of independent reports provides a powerful reason to believe that the reports are true. Formal results by Huemer, M. 1997. “Probability and Coherence Justification.” Southern Journal of Philosophy 35: 463–72, Olsson, E. 2002. “What is the Problem of Coherence and Truth?” Journal of Philosophy XCIX (5): 246–72, Olsson, E. 2005. Against Coherence: Truth, Probability, and Justification. Oxford University Press., Bovens, L., and S. Hartmann. 2003. Bayesian Epistemology. Oxford University Press, prove that, under certain conditions, coherence cannot increase the probability of the target claim. These formal results, known as ‘the impossibility theorems’ have been widely discussed in the literature. They are taken to have significant epistemic upshot. In particular, they are taken to show that reports must first individually confirm the target claim before the coherence of multiple reports offers any positive confirmation. In this paper, I dispute this epistemic interpretation. The impossibility theorems are consistent with the idea that the coherence of independent reports provides a powerful reason to believe that the reports are true even if the reports do not individually confirm prior to coherence. Once we see that the formal discoveries do not have this implication, we can recover a model of coherence justification consistent with Bayesianism and these results. This paper, thus, seeks to turn the tide of the negative findings for coherence reasoning by defending coherence as a unique source of confirmation.

Sharing (mis) information on social networking sites. An exploration of the norms for distributing content authored by others

This article explores the norms that govern regular users’ acts of sharing content on social networking sites. Many debates on how to counteract misinformation on Social Networking Sites focus on the epistemic norms of testimony, implicitly assuming that the users’ acts of sharing should fall under the same norms as those for posting original content. I challenge this assumption by proposing a non-epistemic interpretation of (mis) information sharing on social networking sites which I construe as infrastructures for forms of life found online. Misinformation sharing belongs more in the realm of rumour spreading and gossiping rather than in the information-giving language games. However, the norms for sharing cannot be fixed in advance, as these emerge at the interaction between the platforms’ explicit rules, local norms established by user practices, and a meta-norm of sociality. This unpredictability does not leave us with a normative void as an important user responsibility still remains, namely that of making the context of the sharing gesture explicit. If users will clarify how their gestures of sharing are meant to be interpreted by others, they will implicitly assume responsibility for possible misunderstandings based on omissions, and the harms of shared misinformation can be diminished.

Kolmogorovian versus Non-Kolmogorovian Probabilities in Contextual Theories

Most scholars maintain that quantum mechanics (QM) is a contextual theory and that quantum probability does not allow for an epistemic (ignorance) interpretation. By inquiring possible connections between contextuality and non-classical probabilities we show that a class TμMP of theories can be selected in which probabilities are introduced as classical averages of Kolmogorovian probabilities over sets of (microscopic) contexts, which endows them with an epistemic interpretation. The conditions characterizing TμMP are compatible with classical mechanics (CM), statistical mechanics (SM), and QM, hence we assume that these theories belong to TμMP. In the case of CM and SM, this assumption is irrelevant, as all of the notions introduced in them as members of TμMP reduce to standard notions. In the case of QM, it leads to interpret quantum probability as a derived notion in a Kolmogorovian framework, explains why it is non-Kolmogorovian, and provides it with an epistemic interpretation. These results were anticipated in a previous paper, but they are obtained here in a general framework without referring to individual objects, which shows that they hold, even if only a minimal (statistical) interpretation of QM is adopted in order to avoid the problems following from the standard quantum theory of measurement.

A Interpretação Epistêmica da Semântica Bidimensional

O presente artigo pretende apresentar e avaliar criticamente o projeto racionalista de David Chalmers e Frank Jackson na interpretação epistêmica da chamada semântica bidimensional. Diferentes versões do aparato formal da semântica bidimensional são lançadas para resolver certos problemas no âmbito da filosofia da linguagem, a saber, dar conta do conteúdo semântico de termos indexicais, produzir uma explicação para os híbridos modais como instâncias do necessário a posteriori e contribuir para o debate acerca da determinação do conteúdo mental. De um modo geral, a semântica bidimensional estipula uma dupla dependência de expressões linguísticas frente a possibilidades ou cenários. Uma das noções centrais para a construção das possibilidades relevantes é a noção de “cenário”. O presente trabalho procura responder a duas objeções aa noção de cenário empregada por David Chalmers em sua interpretação do aparato bidimensional. AbstractThis paper aims at presenting and critically assessing the epistemic interpretation advanced by David Chalmers and Frank Jackson of the two-dimensional semantic framework. Different versions of the formal apparatus of the two-dimensional framework are used to account for philosophical phenomena such as the content of indexical terms, modal hybrids, such as posteriori necessities and the individuation of mental content. Generally, two-dimensional framework stipulates a double dependence of linguistic terms on possibilities or scenarios. One of the central notions for the construction of the relevant kind of possibility is the notion of “scenario”. The aim of the paper is to defend the two- dimensional framework from two objections regarding the notion of scenario.

An epistemic interpretation of the posterior likelihood ratio distribution

Often the expression of a likelihood ratio involves model parameters θ. This fact prompted many researchers to argue that a likelihood ratio should be accompanied by a confidence interval, as one would do when estimating θ itself. We first argue against this, based on our view of the likelihood ratio as a function of our knowledge of the model parameters, rather than being a function of the parameters themselves. There is, however, another interval that can be constructed, and which has been introduced in the literature. This is the interval obtained upon sampling from the so-called ‘posterior likelihood ratio distribution’, after removing, say, the most extreme 5% of a sample from this distribution. Although this construction appears in the literature, its interpretation remained unclear, as explicitly acknowledged in the literature. In this article we provide an interpretation: the posterior likelihood ratio distribution tells us which likelihood ratios we can expect if we were to obtain more information. As such, it can play a role in decision making procedures, for instance about the question whether or not it is worthwhile to try to obtain more data. The posterior likelihood ratio distribution has no relevance for the evidential value of the current data with our current knowledge. We illustrate all this with a number of examples.

On epistemic and ontological interpretations of intuitionistic and paraconsistent paradigms

From the technical point of view, philosophically neutral, the duality between a paraconsistent and a paracomplete logic (for example intuitionistic logic) lies in the fact that explosion does not hold in the former and excluded middle does not hold in the latter. From the point of view of the motivations for rejecting explosion and excluded middle, this duality can be interpreted either ontologically or epistemically. An ontological interpretation of intuitionistic logic is Brouwer’s idealism; of paraconsistency is dialetheism. The epistemic interpretation of intuitionistic logic is in terms of preservation of constructive proof; of paraconsistency is in terms of preservation of evidence. In this paper, we explain and defend the epistemic approach to paraconsistency. We argue that it is more plausible than dialetheism and allows a peaceful and fruitful coexistence with classical logic.

Reflective Access, Closure, and Epistemological Disjunctivism

In this paper, I consider the so-called Access Problem for Duncan Pritchard's Epistemological Disjunctivism (2012). After reconstructing Pritchard's own response to the Access Problem, I argue that in order to assess whether Pritchard's response is a satisfying one, we first need an account of the notion of ‘Reflective Access’ that underpins Pritchard's Epistemological Disjunctivism. I provide three interpretations of the notion of Reflective Access: a metaphysical interpretation, a folk interpretation, and an epistemic interpretation. I argue that none of these three interpretations comes without problems. I conclude that, until we have a clear and unproblematic account of Reflective Access, the Access Problem remains a challenge for Pritchard's Epistemological Disjunctivism.

Extreme Points of the Core of Possibility Measures and Maxitive p-Boxes

Under an epistemic interpretation, an upper probability can be regarded as equivalent to the set of probability measures it dominates, sometimes referred to as its core. In this paper, we study the properties of the number of extreme points of the core of a possibility measure, and investigate in detail those associated with (uni- and bi-)variate p-boxes, that model the imprecise information about a cumulative distribution function.