Page 538 - Encyclopedia of Philosophy of Language

Key Figures
bedded sentences it ascribes a force (Kraft). The sense of an expression is both (a) that in virtue of which it has a reference, and (b) the cognitive value of the expression, that is, what is understood by it when one has grasped its meaning or content. The sense of a declarative sentence, for example, is its truth con- dition; the sense of a proper name is the identity con- dition of its bearer; and the sense of a predicate expression is its satisfaction condition. The force of a sentence, on the other hand, is what enables one to distinguish between, say, an assertoric, an imperative, and an interrogative occurrence of one and the same sentence type.
See also: Logic: Historical Survey; Names and Descriptions; Sense.
Bibliography
Bell D 1979 Frege's Theory of Judgement. Clarendon Press, Oxford
Currie G 1982 Frege. An Introduction to his Philosophy. Har- vester Press, Sussex
Dummett M A E 1973 Frege Philosophy of Language. Duck- worth, London
Frege G 1879 Begriffsschrift, eine der arithmetischen nach- gebildete Formelsprache des reinen Denkens. Nebert, Halle. Partial trans, in: Geach P T, Black M (eds.) 1970 Trans- lations from the Philosophical Writings of Gottlob Frege. Blackwell, Oxford
Frege G 1884 Die Grundiagen der Arithmetik. Koebner, Breslau (1950 The Foundations of Arithmetic. Blackwell, Oxford)
Frege G 1892 Ober Sinn und Bedeutung. Zeitschrift fur Philosophic und philosophische Kritik 100: 25-50. Trans, by Black M in: McGuinness B (ed.) 1984
Frege G 1893,1903 Grundgesetze der Arithmetik, Vols. 1 and 2. Pohle, Jena. Partial trans, in: Furth M (ed.) 1964 The Basic Laws of Arithmetic. University of California Press, Berkeley, CA
Frege G 1923 Gedankengefuge. Beitrage zur Philosophic des deutschen Idealismus 3: 36-51. Trans, by Geach P T, Stoothoff R H in: McGuinness B (ed.) 1984
Kneale W, Kneale M 1962 The Development of Logic. Oxford University Press, Oxford
McGuinness B (ed.) 1984 Gottlob Frege: Collected Papers. Blackwell, Oxford
Peter Thomas Geach (b. 1916) studied in Oxford and Cambridge and taught in Birmingham and Leeds. His main work is in philosophical logic, the theory of meaning, and the history of logic (Geach 1962,1972a), but he has also written on logical problems in natural theology and metaphysics (Geach 1977). He has edited and translated the philosophical writings of Gottlob Frege.
Geach's method in logic is to trace back current logical questions to their Fregean, medieval, or even ancient origins. His essays on medieval logic make clear that scholastic logic went into decline not because it was misguided, but because it was too intel- lectually demanding. Traditional philosophical logic is concerned with arguments from metaphysics and natural theology that are expressed in natural language. Modern formal logic, on the other hand, is mainly inspired by mathematical reasoning. It is hardly surprising, then, that philosophical logic, as practiced by Geach, has at least as much relevance for the semantics of natural language as mathematical logic.
The discussion of'donkey sentences' (Geach 1962) has provided the semantic community with enough food for thought for many years.
Every farmer who owns a donkey beats it. (1)
Example (1) is equivalent to the negation of (2). It follows that (1) involves wide scope universal quanti- ficationoverfarmersanddonkeys.Thus,theindefinite noun phrase a donkey in (1) seems to acquire universal force from the context in which it appears. This poses a problem for a compositional analysis of natural language.
The 'program for syntax' (Geach 1972b)—a plea for polymorphic category to type assignment in categorial grammar—has proved to be prophetic in its prediction of the fruitfulness of a flexible approach to categorial grammar. Geach observes that since the rules of cat- egorial grammar are semantically inspirated, syn- tacticians would do well to use the flexibility sanctioned by the intended semantics. For example, instead of combining a functor F with a constituent G(H) consisting itself of a functor/argument com- bination, one may consider F as a functor which first combines with G to form a new functor which then takes argument H. To see that this semantically all right, assume that F, G, H are interpreted as/, g, h, respectively. The semantic effect of the syntax shift is the replacement of function/with a function/* map- pinggtof°g. Inversionsofflexiblecategorialgram- mar formalisms current in the early 1990s the rule A/B -> (AfC)l(B/C), which reflects the category shift for F, is commonly referred to as the Geach rule.
See also: Categorial Grammar; Donkey Sentences.
Some fanner who owns a donkey does not beat it. 516
(2)
Geach, Peter Thomas J. van Eijck