In this paper, Graham Priest’s understanding of dialetheism, the view that there exist true contradictions, is discussed, and various kinds of metaphysical dialetheism are distinguished between. An alternative to dialetheism is presented, namely a thesis called ‘dimathematism’. It is pointed out that dimathematism enables one to escape a slippery slope argument for dialetheism that has been put forward by Priest. Moreover, dimathematism is presented as a thesis that is helpful in rejecting the claim that logic is a normative discipline.

book I. The nature of the state.-- book II. The social foundations of the state.-- book III. The constitution of the state.-- book IV. The administration of the state.-- book V. The state in international intercourse.

Reprint. Originally published: T'ubingen: C.F. Osiander, 1822.

"Die Grundlage... ist... ein Programm, welches ich im vorigen Jahre unter dem Titel: "Historische und philosophische Beitr'age zur Erl'auterung des Spinozismus' ausgegeben habe. Aber... hier... sehr erweitert.".

On cover: Zusammenhang des Spinozismus mit der Cartesianischen Philosophie.

Justification stit logic is a logic for reasoning about proving as a certain kind of activity, namely seeing to it that a proof is publicly available. It merges the semantical analysis of deliberatively seeing-to-it-that from stit theory and the semantics of the epistemic logic with justification from. In this paper, after recalling its language and basic semantical definitions, various ramifications and refinements of justification stit logic are presented and discussed: imposing natural restrictions upon the class of models under consideration, making (...) use of modalities that assert the existence of a proof, introducing a variant of justification stit logic based on a semantics introduced by M. Fitting, and adding variable-binding operators and extending the set of proof polynomials. (shrink)

Model-theoretic proofs of functional completenes along the lines of [McCullough 1971, Journal of Symbolic Logic 36, 15–20] are given for various constructive modal propositional logics with strong negation.

It is shown that the constructive four-valued logic N4 can be faithfully embedded into the modal logic S4. This embedding is used to obtain complete, cut-free display sequent calculi for N4 and C4, the modal logic of consistency over N4. C4 is a natural monotonic base system for semantics-based non-monotonic reasoning.

It is shown that every displayable propositional logic enjoys strong cut-elimination. This result strengthens Belnap's general cut-elimination theorem for Display Logic.

Text: Reproduktion nach Scan der Ausgabe von 1934, Verlag von J. C. B. Mohr (Paul Siebeck) in Tübingen. - Von dem kleinen Buch, das ich hier der Öffentlichkeit übergebe, bitte ich den Leser, nichts anderes zu erwarten, als das, was sein Titel ausdrücklich sagt. Es handelt sich in ihm nicht etwa um die Grundlinien eines Systems der Philosophie, sondern ausschließlich um dessen Probleme, und wenn diese sich auch nicht darlegen lassen, ohne die Richtung anzudeuten, in der das System bei der (...) Ausführung sich zu bewegen hätte, so sollen doch in dieser Schrift hauptsächlich Fragen gestellt, nicht Antworten gegeben werden. Oft brechen die Darlegungen dort ab, wo mancher Leser glauben kann, daß die größten Schwierigkeiten noch ungelöst sind. Ja mehr: nur die Grundprobleme der Philosophie werden erörtert, und das Eingehen auf Sonderfragen ist fast überall vermieden. Einzelheiten sind dann allein herangezogen worden, wenn es zur Verdeutlichung der Hauptbegriffe wünschenswert erschien. [Auszug aus dem Vorwort des Buches]. (shrink)

In this paper it is suggested to generalize our understanding of general (structural) proof theory and to consider it as a general theory of two kinds of derivations, namely proofs and dual proofs. The proposal is substantiated by (i) considerations on assertion, denial, and bi-lateralism, (ii) remarks on compositionality in proof-theoretic semantics, and (iii) comments on falsification and co-implication. The main formal result of the paper is a normal form theorem for the natural deduction proof system N2Int of the bi-intuitionistic (...) logic 2Int. The proof makes use of the faithful embedding of 2Int into intuitionistic logic with respect to validity and shows that conversions of dual proofs can be sidestepped. (shrink)

We consider a labelled tableau presentation of constant domain first-order S5 and prove a strong cut-elimination theorem.

Achievement test differences between boys and girls and between young men and young women, mostly favoring males, extend far beyond mathematics. Such pervasive differences, illustrated here, may require an explanatory theory broader than Geary's.