Following the lead of Duncan Pritchard’s “Wittgensteinian Pyrrhonism,” this paper takes a further, comparative and contrastive look at the problem of justification in Sextus Empiricus and in Wittgenstein’sOn Certainty. I argue both that Pritchard’s stimulating account is problematic in certain important respects and that his insights contain much interpretive potential still to be pursued. Diverging from Pritchard, I argue that it is a significant and self-conscious aspect of Sextus’ sceptical strategies to call into question large segments of our belief systemen (...) masseby exposing as apparently unjustifiable fundamental propositions which are closely related in their linchpin role to Wittgenstein’s hinge propositions. In the first instance, the result is a more complex account of both a deeper affinity between Wittgenstein’s approach to hinge propositions and Sextus’ approach to what I termarchaipropositions and a divergence between the two. In the second instance, I suggest how the comparison withOn Certaintycan be illuminating for the interpreter of Sextus. In particular, it can help us to see how the Pyrrhonist’s everyday conduct—common assumptions to the contrary notwithstanding—involves rational procedures of justification, in line with a naturalism reminiscent of Wittgenstein. Furthermore, it can help us to reflect on the Pyrrhonist’s attitude to what Wittgenstein would have called her ‘worldview’. Throughout, I suggest that the comparison with Wittgenstein is interesting, although it must be cashed out differently, not only on the interpretation—or, perhaps, strand—of ancient Pyrrhonism which has the sceptic exempt ordinary beliefs from her suspension of judgement, but also on the interpretation (or strand) which has her disavow all beliefs categorically. (shrink)

The paper suggests a way of modeling belief changes within the tradition of formal belief revision theories. The present model extends the scope of traditional proposals, such as AGM, so as to take care of “structural belief changes” – a type of radical shifts that is best illustrated with, but not limited to, instances of scientific discovery; we obtain AGM expansions and contractions as limiting cases. The representation strategy relies on a non-standard use of a semantic machinery. More precisely, the (...) model seeks to correlate knowledge states with interpretations of a given formal language L, in such a way that the epistemic state of an agent at a given time gives rise to a picture of how things could be, if there weren’t anything else to know. Interpretations of L proceed along supervaluational ideas; hence, the model as a whole can be seen as a particular application of supervaluational semantics to epistemic matters. (shrink)

I develop a strategy for representing epistemic states and epistemic changes that seeks to be sensitive to the difference between voluntary and involuntary aspects of our epistemic life, as well as to the role of pragmatic factors in epistemology. The model relies on a particular understanding of the distinction between full belief and acceptance , which makes room for the idea that our reasoning on both practical and theoretical matters typically proceeds in a contextual way. Within this framework, I discuss (...) how agents can rationally shift their credal probability functions so as to consciously modify some of their contextual acceptances; the present account also allows us to represent how the very set of contexts evolves. Voluntary credal shifts, in turn, might provoke changes in the agent’s beliefs, but I show that this is actually a side effect of performing multiple adjustments in the total lot of the agent’s acceptance sets. In this way we obtain a model that preserves many pre-theoretical intuitions about what counts as adequate rationality constraints on our actual practices—and hence about what counts as an adequate, normative epistemological perspective. (shrink)

En este trabajo argumento a favor de la idea de que una explicación científica es una respuesta a una pregunta, aunque no necesariamente a una pregunta-por-qué. Esto no quiere decir que las preguntas-por-qué no sean elementos fundamentales de toda investigación científica: su importancia radica en que son capaces de organizar y sistematizar un conjunto dado de creencias. Para justificar esta afirmación, comienzo por identificar tres estadios básicos en los cuales pueden surgir preguntas-por-qué, y luego procedo a caracterizar su estructura. Muestro (...) finalmente cómo usar este análisis para elucidar la noción de poder de unificación de hipótesis rivales. Entiendo que esta última noción, a su vez, constituye uno de los criterios que debemos considerar a la hora de evaluar cuál de dichas hipótesis rivales es la mejor explicación disponible, comparativamente hablando. In this paper I take scientific explanations to be answers to questions, though not necessarily to why-questions. This, however, is not meant to imply that why-questions are not fundamental in their own peculiar way. As I understand it, why-questions are crucial elements in any research process because they are able to organize and systematize an agent's belief set. In order to justify my claim I start by identifying three basic stages in which whyquestions can arise, and then I proceed to characterize their structure. I also show how to use this analysis to elucidate the notion of comparative unification power of rival hypotheses. The notion of comparative unification power, in turn, can be thought of as one of the criteria that we should take into account at the time of assessing which of such rival hypotheses is the best explanation available, comparatively speaking. (shrink)