We propose an epistemic logic in which knowledge is fully introspective and implies truth, although truth need not imply epistemic possibility. The logic is presented in sequential format and is interpreted in a natural class of partial models, called balloon models. We examine the notions of honesty and circumscription in this logic: What is the state of an agent that ‘only knows φ’ and which ...

ROBERT SMITHSON: Apriority, Super-Rigidity, and Fregean Content (Under the direction of William Lycan) What is the difference between an utterance of the sentence 'Hesperus is Hesperus' and an utterance of the sentence 'Hesperus is Phosphorus'? David Chalmers claims that these sentences are psychologically and epistemologically distinct because they are associated with distinct fine-grained Fre...

My thesis is that backwards time travel can occur without causal loops. Specifically, I shall show that assuming that backwards time travel (‘time travel’ for short) is logically possible, it is logically possible to have a world where time travel occurs and yet no causal loops occur. To formulate this thesis more precisely, I need to distinguish two types of causal loops, closed and open causa...

We want to show the difference between the degrees of possibilities (or necessities) and the degrees of belief (or plausibility). The overall principle is that the degrees of possibilities and necessities are the extensions of the modal concept of possibility and necessity whereas degrees of belief and plausibility are related to a language at a metalevel. Two models are considered: the transfe...

A DataSpace Support Platform (DSSP) is a self-sustained and self-managed system which needs to support uncertainty among its mediated schemas and its schema mappings. Some approaches for managing such uncertainty by assigning probabilities and reliability degrees to schema mappings have been proposed. Unfortunately, the number of mappings self-generated by a DSSP is usually too large and among ...

Infallibilism is the claim that knowledge requires that one satisfies some infallibility condition. I spell out three distinct such conditions: epistemic, evidential and modal infallibility. Epistemic infallibility turns out to be simply a consequence of epistemic closure, and is not infallibilist in any relevant sense. Evidential infallibilism i s unwarranted but it is not an satisfactory char...

Kripke (1980) famously separates the metaphysical and epistemic modal domains, with supposed necessary a posteriori identity statements such as ‘Hesperus is Phosphorus’, appearing to create an irreconcilable gap between conceivability and possibility. In response to this problem, David Chalmers (2002, 2004a, 2006) uses two-dimensional modal semantics (2DS) to claim that conceivability entails p...

This kind of category ambiguity has been cited as evidence against the logical possibility of learning grammatical categories from distribution (Pinker 1987). Indeed, if we are to take seriously the many proposals that children may learn which words should be categorized together based on such cues as local co-occurrence (e.g., Redington, Chater & Finch 1998; Mintz 2003), we must address the po...

We develop a mathematical theory for comparative sorites, considered in terms of a system mapping pairs of stimuli into a binary response characteristic whose values supervene on stimulus pairs and are interpretable as the complementary relations ‘are the same’ and ‘are not the same’ (overall or in some respect). Comparative sorites is about hypothetical sequences of stimuli in which every two ...

The new …eld of judgment aggregation aims to …nd collective judgments on logically interconnected propositions. Recent impossibility results establish limitations on the possibility to vote independently on the propositions. I show that, fortunately, the impossibility results do not apply to a wide class of realistic agendas once propositions like “if a then b” are adequately modelled, namely a...