Online research in philosophy

Lautemann et al. (1995) gave a descriptive characterisation of the class of context-free languages, showing that a language is context-free iff it is definable as the set of words satisfying some sentence of a particular logic (fragment) over words. The present notes discuss how to specialise this result to the class of linear languages. Somewhat surprisingly, what would seem the most straightforward specialisation actually fails, due to the fact that linear grammars fail to admit a Greibach normal form. We identify an alternative specialisation, based on an alternative characterisation of context-free languages, also noted by Lautemann et al. (1995).

My focus here will be Rudolf Carnap’s views on ontology, as these are presented in the seminal “Empiricism, Semantics and Ontology” (1950). I will first describe how I think Carnap’s distinction between external and internal questions is best understood. Then I will turn to broader issues regarding Carnap’s views on ontology. With certain reservations, I will ascribe to Carnap an ontological pluralist position roughly similar to the positions of Eli Hirsch and the later Hilary Putnam. Then I turn to some interrelated arguments against the pluralist view. The arguments are not demonstrative. Some possible escape routes for the pluralist are outlined. But I think the arguments constitute a formidable challenge. There should be serious doubt as to whether the pluralist view, as it emerges after discussion of these arguments, will be worth defending. Moreover, there is an alternative ontological view which equally well subserves the motivations underlying ontological pluralism.

This article spells out the reasons for calling God a substance and argues that theism nevertheless does not require substance ontology. It is compatible with an alternative ontology which I call stuff ontology.

Recently, there have been some attempts towards developing programming languages based on situation theory. These languages employ situation-theoretic constructs with varying degrees of divergence from the ontology of the theory. In this paper, we review three of these programming languages.

In contemporary debates about ontology, one prominent skeptical view emphasizes the existence of different possible languages for doing ontology. Eli Hirsch, in recent years the most prominent proponent of a view like this, has defended the claim that “many familiar questions about the ontology of physical objects are merely verbal. Nothing is substantively at stake in these questions beyond the correct use of language” and the claim that “quantifier expressions can have different meaning in different languages”.1 Ted Sider, while critical of the type of view Hirsch defends, has in many places prominently singled it out for critical discussion. In his (2001), he associates with Carnap the view that “different frameworks employ different semantic rules for the quantifiers”, and says that a theorist in Carnap’s tradition would say that the stuff-ontologist and the thing-ontologist have different “frameworks” and that “[W]ithin these frameworks there are answers to what there is, but any question about which framework is the right framework is metaphysical in the pejorative sense of being a pseudo-question”.2 In his (forthcoming), Sider discusses at length the view that disputants in ontological disputes use the same sentences with different meaning and hence in fact each speak the truth, and what he describes as the attendant view that “there are multiple candidate meanings for the quantifiers”.3 In his (2005), Cian Dorr critically discusses “the idea that there are many different possible languages which differ systematically in the truth-values they assign to general ontological claims”.4..

The book highlights the concept of ontology, relationship between language and ontology, the distinction between ontology and reality, the role of linguistic ...

Ontology languages for the Semantic Web have their strengths and weaknesses, in particular in the light of deploying them for biological and medical information systems. We survey and compare the Description Logics-based OWL languages, and the DL-Lite and DLR families of languages. Language choices that an ontology developer has to make are, among others, expressivity with n-ary relations (where n > 2) and more role properties versus ontology usage for data-intensive tasks. Guidelines are suggested to facilitate choosing the language best fitted for a task.

In a series of publications, Eli Hirsch has presented a sustained defense of common-sense ontology. Hirsch's argument relies crucially on a meta-ontological position sometimes known as ‘superficialism’. Hirsch's argument from superficialism to common-sense ontology is typically resisted on the grounds that superficialism is implausible. In this paper, I present an alternative argument for common-sense ontology, one that relies on (what I argue is) a much more plausible meta-ontological position, which I call ‘constructivism’. Note well: I will not quite argue that constructivism is true; merely that it is significantly more plausible than superficialism, and consequently affords a safer route to common-sense ontology. Thus my main goal in the paper is not quite to establish common-sense ontology, nor for that matter to refute Hirsch's argument for it. My goal is, in a way, more expressive than argumentative: I wish to articulate a novel meta-ontological position, one that I take to be in no way obviously less plausible than already familiar positions, and to point out that the position probably leads to common-sense ontology. I open, in section 1, with a discussion of Hirsch's argument and the main objection to it. I then develop, in section 2, a sketch of the alternative meta-ontology I have in mind. I close, in section 3, with the argument that this alternative meta-ontology, too, leads to common-sense ontology.

The semantic web ontology languages RDFS and OWL are widely used but limited in both their expressivity and their support for modularity and integrated documentation. Expressivity, modularity, and documentation of formal knowledge have always been important issues in the MKM community. Therefore, we try to improve these ontology languages by well-tried MKM techniques. Concretely, we propose OM- Doc as an alternative. We show how OMDoc can be made compatible with semantic web ontology languages, focusing on knowledge representation, modular design, documentation, and metadata. We evaluate our technology by re-implementing the Friend-of-a-friend (FOAF) ontology and applying it in a novel metadata framework for technical documents (including ontologies).

A sense of unity -- Basic objects : a reply to Xu -- Objectivity without objects -- The vagueness of identity -- Quantifier variance and realism -- Against revisionary ontology -- Comments on Theodore Sider's four dimensionalism -- Sosa's existential relativism -- Physical-object ontology, verbal disputes, and common sense -- Ontological arguments : interpretive charity and quantifier variance -- Language, ontology, and structure -- Ontology and alternative languages.