The primary aim is the reconstruction of the main argument of the second chapter of Anselm’s Proslogion. To be proved is the statement that God, or something than which nothing greater can be thought, exists in reality. I proceed by a piecemeal analysis of every sentence of the Latin original and its subsequent translation into a formal second-order language with choice operator. Reconstructing Anselm’s reasoning demands interpretative input and additions. For example, the formula ‘quod maius est’ has to be suitably (...) interpreted and expanded. Furthermore, I try to explicate Anselm’s maius predicate in terms of a perfection predicate and to develop a general proof for Anselm’s theorem, i.e. the statement that something/that than which something greater cannot be thought has all greater-making attributes. (shrink)

Gegen die vielfach vertretene Auffassung, Frege habe die Hilbertsche Axiomatik nicht verstanden, wird nachzuweisen versucht, daß Frege die neue Methode nicht nur verstanden, sondem auch begrifflich präzise analysiert hat. Er definiert eine formale Theorie im Hilbertschen Sinn als eine Klasse von logisch beweisbaren Wenn-dann-Sätzen, die freie Variable enthalten und deren Wenn-Satz eine Konjunktion der Axiome im Hilbertschen Sinn ist. Er untersucht ferner das Verhältnis zwischen einer Hilbertschen Theorie und ihren Modellen (Anwendungen) und wendet seine allgemeinen Ergebnisse in erhellender Weise auf (...) Hilberts Grundlagen der Geometrie an. (shrink)

This paper consists of two parts. Part I contains a precise model-theoretic reconstruction of Quine's criterion for the ontological presuppositions of a theory. Two versions (K1), (K2) of the criterion are elaborated, (K2) being the more adequate one which is shown through a number of theorems for each version. Part II contains a critical discussion of (K2), in particular of the question wether (K2) is a criterion for ontological presuppositions, i.e. for entities existing independently of the theory. Its answer depends (...) on the meaning of the quantifiers used in (K2). It is shown that this meaning, contrary to Quine's opinion, does not commit one to the existence of entities. Quine's criterion is therefore not a criterion for ontological presuppositions of theories. If theories at all presuppose independently existing entities, then it is not by using the standard quantifiers of classical logic. One of the consequences of this result is that there is no need for a free logic, which is shown by discussing a system of Lambert and Meyer. Another consequence is that there is no problem about negative existentials. (shrink)