It is the aim of the present study to introduce the reader to the ways of thinking of those contemporary philosophers who apply the tools of symbolic logic to classical philosophical problems. Unlike the "conti nental" reader for whom this work was originally written, the English speaking reader will be more familiar with most of the philosophers dis cussed in this book, and he will in general not be tempted to dismiss them indiscriminately as "positivists" and "nominalists." But the English version of this study may help to redress the balance in another respect. In view of the present emphasis on ordinary language and the wide spread tendency to leave the mathematical logicians alone with their technicalities, it seems not without merit to revive the interest in formal ontology and the construction of formal systems. A closer look at the historical account which will be given here, may convince the reader that there are several points in the historical develop ment whose consequences have not yet been fully assessed: I mention, e. g., the shift from the traditional three-level semantics of sense and deno tation to the contemporary two-level semantics of representation; the relation of extensional structure and intensional content in the extensional systems of Wittgenstein and Carnap; the confusing changes in labelling the different kinds of analytic and apriori true sentences; etc. Among the philosophically interesting tools of symbolic logic Lesniewski's calculus of names deserves special attention."

It is the aim of the present study to introduce the reader to the ways of thinking of those contemporary philosophers who apply the tools of symbolic logic to classical philosophical problems. Unlike the "conti nental" reader for whom this work was originally written, the English speaking reader will be more familiar with most of the philosophers dis cussed in this book, and he will in general not be tempted to dismiss them indiscriminately as "positivists" and "nominalists." But the English version of this study may help to redress the balance in another respect. In view of the present emphasis on ordinary language and the wide spread tendency to leave the mathematical logicians alone with their technicalities, it seems not without merit to revive the interest in formal ontology and the construction of formal systems. A closer look at the historical account which will be given here, may convince the reader that there are several points in the historical develop ment whose consequences have not yet been fully assessed: I mention, e. g., the shift from the traditional three-level semantics of sense and deno tation to the contemporary two-level semantics of representation; the relation of extensional structure and intensional content in the extensional systems of Wittgenstein and Carnap; the confusing changes in labelling the different kinds of analytic and apriori true sentences; etc. Among the philosophically interesting tools of symbolic logic Lesniewski's calculus of names deserves special attention."

a) Das sprachlich-Iogische Interesse der Gegenwartsphilosophie Wer die zeitgenossische philosophische Diskussion verfolgt, dem muB sogleich auffallen, wie sehr heute in vielen Kreisen der Zugang zu allen Problemen yom SprachIichen und Logischen her gesucht wird, wie der Gebrauch von Wortern und Zeichen, wie die fiir deren Systeme geltenden Gesetze ins Zentrum der Aufmerksamkeit geruckt sind. EinfluBreiche philosophische Bucher tragen Titel wie: "Logisch-philosophische Ab- handlung", "Der logische Aufbau der Welt", "Der Wahrheitsbegriff in den formaIisierten Sprachen", "Ethik und Sprache"l, um nur einige besonders wichtige und charakteristische Werke aus der Fulle der vor- handenen herauszugreifen. 1m Zusammenhang damit ist ein hoch- entwickeltes technisches Niveau der Terminologie erreicht worden, und Ergebnisse von groBer philosophischer Tragweite sind zu verzeichnen; vor allem die neuen Einsichten in die Moglichkeiten und Grenzen der FormaIisierung sind von kaum zu uberschatzender Wichtigkeit2. Besonders symptomatisch fur das Anwachsen des dem Sprachlichen und Logischen bezeugten Interesses ist die seit der Jahrhundertwende an verschiedenen Orten neu einsetzende Ausarbeitung einer ganz all- gemeinen Theorie der Zeichen. Denker wie C. S. PEmcE, E. HUSSERL nnd F. DE SAUSSURE, welchc voneinander weitgehendst unabhangigen Traditionen angehoren, stehen am Ausgangspunkt dieser Entwicklung. Da die einzelnen Linien dieser Entwicklung bisher noch kaum neben- einander gesetzt worden sind, diirfte ein Versuch, sie kurz zu skizzieren, erwiinscht sein: In den Vereinigten Staaten ist es der mathematische Logiker C. S. PEIRCE (1839-1914), der eine allgemeine Zeichentheorie ("semiotic") begriindete und ihr die Untersuchung der sprachlichen Zeichen unterordnete.