In this paper the arguments for optimal data selection and the contrast class account of negations in the selection task and the conditional inference task are summarised, and contrasted with the matching bias approach. It is argued that the probabilistic contrast class account provides a unified, rational explanation for effects across these tasks. Moreover, there are results that are only explained by the contrast class account that are also discussed. The only major anomaly is the explicit negations effect in the (...) selection task (Evans, Clibbens, & Rood, 1996), which it is argued may not be the result of normal interpretative processes. It is concluded that the effects of negation on human reasoning provide good evidence for the view that human reasoning processes may be rational according to a probabilistic standard. (shrink)

L’auteur discerne trois intuitions majeures dans la théorie éliminativiste de la négation développée par les idéalistes anglais, d’après laquelle une négation est l’élimination d’une alternative au sein d’un ensemble complet d’alternatives disjonctivement affirmées du sujet de la négation : premièrement, la détermination du sens d’une proposition est l’assignation à une proposition de coordonnées logiques dans un espace logique ; deuxièmement, le sens d’une proposition entretient une relation interne avec le sens de sa négation ; troisièmement, l’espace logique dans lequel une (...) négation acquiert un sens dépend du contexte. Il est montré que la théorie éliminativiste de la négation échoue à composer adéquatement les deux premiers aperçus en essayant de faire droit au troisième. A l’inverse, le Tractatus de Wittgenstein les combine adéquatement mais passe à côté du troisième. Une théorie adéquate de la négation devrait, minimalement, satisfaire simultanément les trois contraintes. (shrink)

The version of the paradox of false judgement examined at Tht. 188c10–189b9 relies on the assumption that to judge falsehoods is to judge the things which are not. The presentation of the argument displays several syntactic ambiguities: at several points it allows the reader to adopt different syntactic connections between the components of sentences. For instance, when Socrates says that in a false judgement the cognizer is “he who judges the things which are not about anything whatsoever” (188d3–4), how should (...) the clause “about anything whatsoever” be construed? In common with “he who judges” and “the things which are not” (in which case the cognizer would be “he who judges about anything whatsoever the things which are not about it”), or exclusively with “he who judges” (in which case the cognizer would be “he who judges about anything whatsoever the things which are not”)? The most plausible answer is that both construals are envisaged. Accordingly, the argument has two branches corresponding to these two alternative construals. In particular, it attempts to show that in both cases the cognizer will address what does not exist – an impossibility. The idea that a false judgement is concerned with what is not about its reference has a clear echo in the Sophist. The way in which the problem is handled in the Theaetetus provides a hint that can help to find a solution for the hotly debated issue of the interpretation of the Sophist’s account of false statement. (shrink)