The philosophy of modality investigates necessity and possibility, and related notions--are they objective features of mind-independent reality? If so, are they irreducible, or can modal facts be explained in other terms? This volume presents new work on modality by established leaders in the field and by up-and-coming philosophers. Between them, the papers address fundamental questions concerning realism and anti-realism about modality, the nature and basis of facts about what is possible and what is necessary, the nature of modal knowledge, modal logic and its relations to necessary existence and to counterfactual reasoning. The general introduction locates the individual contributions in the wider context of the contemporary discussion of the metaphysics and epistemology of modality.

Necessary Beings is concerned with two central areas of metaphysics: modality-the theory of necessity, possibility, and other related notions; and ontology-the general study of what kinds of entities there are. Bob Hale's overarching purpose is to develop and defend two quite general theses about what is required for the existence of entities of various kinds: that questions about what kinds of things there are cannot be properly understood or adequately answered without recourse to considerations about possibility and necessity, and that, conversely, questions about the nature and basis of necessity and possibility cannot be satisfactorily tackled without drawing on what might be called the methodology of ontology. Taken together, these two theses claim that ontology and modality are mutually dependent upon one another, neither more fundamental than the other. Hale defends a broadly Fregean approach to metaphysics, according to which ontological distinctions among different kinds of things (objects, properties, and relations) are to be drawn on the basis of prior distinctions between different logical types of expression. The claim that facts about what kinds of things exist depend upon facts about what is possible makes little sense unless one accepts that at least some modal facts are fundamental, and not reducible to facts of some other, non-modal, sort. He argues that facts about what is absolutely necessary or possible have this character, and that they have their source or basis, not in meanings or concepts nor in facts about alternative 'worlds', but in the natures or essences of things.

The philosophy of modality investigates necessity and possibility, and related notions-are they objective features of mind-independent reality? If so, are they irreducible, or can modal facts be explained in other terms? This volume presents new work on modality by established leaders in the field and by up-and-coming philosophers. Between them, the papers address fundamental questions concerning realism and anti-realism about modality, the nature and basis of facts about what is possible and what is necessary, the nature of modal knowledge, modal logic and its relations to necessary existence and to counterfactual reasoning. The general introduction locates the individual contributions in the wider context of the contemporary discussion of the metaphysics and epistemology of modality.

Bob Hale and Crispin Wright draw together here the key writings in which they have worked out their distinctive approach to the fundamental questions: what is mathematics about, and how do we know it? The volume features much new material: introduction, postscript, bibliographies, and a new essay on a key problem. The Reason's Proper Study is the strongest presentation yet of the controversial neo-Fregean view that mathematical knowledge may be based a priori on logic and definitional abstraction principles. It will prove indispensable reading not just to philosophers of mathematics but to all who are interested in the fundamental metaphysical and epistemological issues which the programme raises.

Necessary Beings is concerned with two central areas of metaphysics: modality-the theory of necessity, possibility, and other related notions; and ontology-the general study of what kinds of entities there are. Bob Hale's overarching purpose is to develop and defend two quite general theses about what is required for the existence of entities of various kinds: that questions about what kinds of things there are cannot be properly understood or adequately answered without recourse to considerations about possibility and necessity, and that, conversely, questions about the nature and basis of necessity and possibility cannot be satisfactorily tackled without drawing on what might be called the methodology of ontology. Taken together, these two theses claim that ontology and modality are mutually dependent upon one another, neither more fundamental than the other. Hale defends a broadly Fregean approach to metaphysics, according to which ontological distinctions among different kinds of things (objects, properties, and relations) are to be drawn on the basis of prior distinctions between different logical types of expression. The claim that facts about what kinds of things exist depend upon facts about what is possible makes little sense unless one accepts that at least some modal facts are fundamental, and not reducible to facts of some other, non-modal, sort. He argues that facts about what is absolutely necessary or possible have this character, and that they have their source or basis, not in meanings or concepts nor in facts about alternative 'worlds', but in the natures or essences of things.

Essays on Existence and Essence presents a series of writings-including several previously unpublished-by Bob Hale on the topics of ontology and modality. The essays develop and consolidate a number of themes central to his work and to contemporary metaphysics, logic, and philosophy of language. They display Hale's innovative approach to some of the most fundamental issues in philosophy, in dialogue (and, in some cases, in collaboration) with other leading philosophers. The notion of a definition is examined as it applies both to words-verbal definitions-and to things-real definitions-and the relations between these are brought out in order to address problems in the metaphysics of necessity and the semantics and epistemology of modality. Hale argues for an essentialist theory of the source of necessity and our knowledge of it, and provides rigorous and inventive responses to problems such a theory might face. This theoretical framework is applied to the recently influential truthmaking approach to semantics and logic, developing an exact truthmaker account of universal quantification and modal statements. Other topics covered include the Fregean theory of ontological categories, the status of second-order logic, the metaphysics of numbers, and the nature of analytic propositions. The volume opens with a substantial introduction by Kit Fine, providing a critical examination of Hale's philosophy, and closes with a complete bibliography of Hale's writings.