Systems of modal logic for impossible worlds

The intuitive notion behind the usual semantics of most systems of modal logic is that of ‘possible worlds’. Loosely speaking, an expression is necessary if and only if it holds in all possible worlds; it is possible if and only if it holds in some possible world. Of course, contradictory expressions turn out to hold in no possible worlds, and logically true expressions turn out to hold in every possible world. A method is presented for transforming standard modal systems into systems of modal logic for impossible worlds. To each possible world there corresponds an impossible world such that an expression holds in the impossible world if and only if it does not hold in the possible world. One can then talk about such worlds quite consistently, and there seems to be no logical reason for excluding them from consideration.     

Quantified modal logic: Non-normal worlds and propositional attitudes

One way to obtain a comprehensive semantics for various systems of modal logic is to use a general notion of non-normal world. In the present article, a general notion of modal system is considered together with a semantic framework provided by such a general notion of non-normal world. Methodologically, the main purpose of this paper is to provide a logical framework for the study of various modalities, notably prepositional attitudes. Some specific systems are studied together with semantics using non-normal worlds of different kinds.     

The theory of meaning and some related theories of the learning of language

There are two basically different sorts of theory of meaning and the sort of theory one adopts has a great deal to do with the view one takes of the learning of language. Corresponding to the two kinds of theory of meaning two theories of the learning of language are delineated and the issues that are disputed by them clarified. The logical question of whether each theory is intelligible in itself is first discussed, and, it being concluded that both are genuine empirical hypotheses, an examination is made of psychological grounds for preferring one or the other. While no final decision is arrived at, it is argued that there are grounds for preferring one of the theories.     

Towards a cognitive theory of existential meaning

The capacity to attribute meaning to personal experiences may rest on a specialized cognitive system enabling this form of causal reasoning. Close examination of these attributional tendencies suggests that this system may be distinct from those underlying other forms of causal reasoning such as a “theory of mind” system in the behavioral domain, a folk physics system in the physical domain, and a folk biology system in the biological domain. A fourth, existential domain, an abstract ontological frame within which the subjective, narrative self is envisioned to be contained, may have driven the construction of an intuitive capacity in humans that encourages them to search for the underlying purpose or reason for having had certain life experiences. This system likely has specific, definable operational rules that are responsible for activating such explanatory searches. In addition, it appears anchored to a general intentionality system that promotes the attribution of teleological purpose and higher-order mental states to an abstract agency that is envisioned to cause events and personal experiences. Identifying the component parts of this specialized cognitive system through empirical investigations can help researchers to reconstruct both its evolutionary phylogeny and to track its developmental emergence.     

A theory of meaning

A theory of word meaning developed jointly by Adrienne and Keith Lehrer is summarized, which accommodates the empirical facts of natural languages, especially the diversity of types of words. Reference characterizes the application of words to things, events, properties, etc. and sense the relationship among words and linguistic expressions. Although reference and sense are closely connected, neither can be reduced to the other. We use the metaphor of vectors to show how different, sometimes competing forces interact to provide an understanding of what a word in context means. Topics discussed include vagueness, indeterminacy, the role of experts, possible worlds, pragmatic influences, semantic change, semantic networks, fields, and entailments. A formal theory for understanding the relationship of idiolects, dialects, and communal languages is proposed to account for the dynamic interaction of individuals and communities which occurs continuously.     

Literal meaning and psychological theory

This paper evaluates the psychological status of literal meaning. Most linguistic and philosophical theories assume that sentences have well-specified literal meanings which represent the meaning of a sentence independent of context. Recent debate on this issue has centered on whether literal meaning can be equated with context-free meaning, or whether a sentence's literal meaning is determined only given a set of background assumptions. Neither of these positions meet the demands of a psychological theory of language understanding. Sentences do not have well-defined literal meanings, regardless of whether these are determined in light of a set of background assumptions. Moreover, the putative literal meanings of sentences do not contribute in systematic ways toward the understanding of speakers' utterance meanings. These observations suggest that the distinctions between literal and metaphoric meanings, and between semantics and pragmatics, have little psychological validity.     

Concrete possible worlds and counterfactual conditionals: Lewis versus Williamson on modal knowledge

The epistemology of modality is gradually coming to play a central role in general discussions about modality. This paper is a contribution in this direction, in particular I draw a comparison between Lewis’s Modal realism and Timothy Williamson’s recent account of modality in terms of counterfactual thinking. In order to have criteria of evaluation, I also formulate four requirements which are supposed to be met by any theory of modality to be epistemologically adequate.