Zwart and Franssen’s impossibility theorem reveals a conflict between the possible-world-based content-definition and the possible-world-based likeness-definition of verisimilitude. In Sect. 2 we show that the possible-world-based content-definition violates four basic intuitions of Popper’s consequence-based content-account to verisimilitude, and therefore cannot be said to be in the spirit of Popper’s account, although this is the opinion of some prominent authors. In Sect. 3 we argue that in consequence-accounts , content-aspects and likeness-aspects of verisimilitude are not in conflict with each other, but (...) in agreement . We explain this fact by pointing towards the deep difference between possible-world- and the consequence-accounts, which does not lie in the difference between syntactic (object-language) versus semantic (meta-language) formulations, but in the difference between ‘disjunction-of-possible-worlds’ versus ‘conjunction-of-parts’ representations of theories. Drawing on earlier work, we explain in Sect. 4 how the shortcomings of Popper’s original definition can be repaired by what we call the relevant element approach. We propose a quantitative likeness-definition of verisimilitude based on relevant elements which provably agrees with the qualitative relevant content-definition of verisimilitude on all pairs of comparable theories. We conclude the paper with a plea for consequence-accounts and a brief analysis of the problem of language-dependence (Sect. 6). (shrink)
The paper offers a matrix-based logic (relevant matrix quantum physics) for propositions which seems suitable as an underlying logic for empirical sciences and especially for quantum physics. This logic is motivated by two criteria which serve to clean derivations of classical logic from superfluous redundancies and uninformative complexities. It distinguishes those valid derivations (inferences) of classical logic which contain superfluous redundancies and complexities and are in this sense from those which are or in the sense of allowing only the most (...) informative consequences in the derivations. The latter derivations are strictly valid in RMQ, whereas the former are only materially valid. RMQ is a decidable matrix calculus which possesses a semantics and has the finite model property. It is shown in the paper how RMQ by its strictly valid derivations can avoid the difficulties with commensurability, distributivity, and Bell's inequalities when it is applied to quantum physics. (shrink)
This article proposes a basic logic for application in physics dispensing with the Principle of Excluded Middle. It is based on the article “Matrix Based Logics for Application in Physics (RMQ) which appeared 2009. In his article with Stachow on the Principle of Excluded Middle in Quantum Logic (QL), Peter Mittelstaedt showed that for some suitable QLs, including their own, the Principle of Excluded Middle can be added without any harm for QL; where ‘without any harm for QL’ means that (...) the basic desiderata and the basic results (theorems) of those QLs remain satised in the sense that they avoid the well known difficulties with commensurability and distributivity.In the following article I want to show that the basic desiderata and results (theorems) of RMQ (of avoiding the well-known difficulties with commensurability, distributivity, fusion and Bell’s inequalities) remain satised if by introducing a strong negation (or strong negation and disjunction) the resulting weak intuitionist system RMQI dispenses with the Principle of Excluded Middle; it becomes either invalid or not strictly valid. (shrink)
The purpose of the paper is to show that by cleaning Classical Logic (CL) from redundancies (irrelevances) and uninformative complexities in the consequence class and from too strong assumptions (of CL) one can avoid most of the paradoxes coming up when CL is applied to empirical sciences including physics. This kind of cleaning of CL has been done successfully by distinguishing two types of theorems of CL by two criteria. One criterion (RC) forbids such theorems in which parts of the (...) consequent (conclusion) can be replaced by arbitrary parts salva validitate of the theorem. The other (RD) reduces the consequences to simplest conjunctive consequence elements. Since the application of RC and RD to CL leads to a logic without the usual closure conditions, an approximation to RC and RD has been constructed by a basic logic with the help of finite (6-valued) matrices. This basic logic called RMQ (relevance, matrix, Quantum Physics) is consistent and decidable. It distinguishes two types of validity (strict validity) and classical or material validity. All theorems of CL (here: classical propositional calculus CPC) are classically or materially valid in RMQ. But those theorems of CPC which obey RC and RD and avoid the difficulties in the application to empirical sciences and to Quantum Physics are separated as strictly valid in RMQ. In the application to empirical sciences in general the proposed logic avoids the well known paradoxes in the area of explanation, confirmation, versimilitude and Deontic Logic. Concerning the application to physics it avoids also the difficulties with distributivity, commensurability and with Bell's inequalities. (shrink)
The aim of the book is to show that the ’five ways’ of Thomas Aquinas, i.e., his five arguments to prove the existence of God, are logically correct arguments by the standards of modern predicate logic. In the first chapter this is done by commenting on the two preliminary articles preceding the five ways in which Thomas Aquinas points out that on the one hand the existence of God is not self-evident to us and on the other hand, that, similar (...) as in some scientific explanations, the mere existence of a cause for an effect which is evidently known to us can be proved. In the second chapter every argument is translated into the symbolic form of predicate logic and its logical validity is shown. Additionally a detailed and critical discussion of the premises of each argument is given. (publisher). (shrink)
This paper investigates Brentano's criticism of the correspondence theory of truth within the context of a discussion of his ontological assumptions. Brentano's interpretation of the formula Veritas est adaequatio rei et intellectus and of the principle ens et verum convertuntur is shown to fit into the history of these principles and into modern interpretations like that of Tarski.
SummaryIn the first part of the paper necessary conditions for the rationality of the notions of belief, knowledge, and assumption are given: Among the different conditions it is stressed that one needs two different concepts of belief, one such that if someone knows something he also believes it, the other exclusive such that if someone knows something he need not to believe it and if he believes it he does not yet know it. Another important point is that deductive infallibility (...) has to be rejected as not being a property of human rationality. Similarly it is not a property of human rationality to know all logical true statements.The second chapter offers a deductive system which meets these and additional conditions of human rationality. The third chapter contains the semantics of the deductive system.RésuméDans le premier chapitre ľauteur énumére des conditions nécessaires à la rationalité des concepts croire, savoir et admettre. Entre autres, il relève qu'il faut distinguer au moins deux concepts croire, qui satisfont ľun àľénoncé: quand quelqu'un sait quelque chose, il la croit aussi, ľautre plus exclusif à: quand quelqu'un sait quelque chose, il n'a pas besoin de la croire et quand quelqu'un la croit , il ne la sait pas . Un autre point très important est que ľinfaillibilité déductive doit être rejetée comme n'appartenant pas à la rationalité humaine. Idem pour la connaissance de tous les énoncés logiquement vrais.Le deuxième chapitre décrit un système déductif qui remplit ces conditions de rationalité . Le troisième, la sémantique de ce système.ZusammenfassungIm ersten Kapitel werden notwendige Bedingungen für die Rationalität der Begriffe Glauben, Wissen und Annehmen gegeben: Unter anderem wird hervorgehoben, dass minde‐stens zwei verschiedene Begriffe von Glauben nötig sind; einmal so, dass gilt: wenn einer etwas weiss, dann glaubt er es auch, und dann auch im exklusiven Sinn: wenn einer etwas weiss, dann braucht er es nicht zu glauben und wenn einer etwas glaubt, dann weiss er es nicht. Ein anderer sehr wichtiger Punkt ist, dass deduktive Infallibilität (d.h. dass man von dem. (shrink)
The paper is divided into the following sections: In the first section a short historical survey is given which presents precursors of both Tarski’s truth-condition and Tarski’s truth definition . Secondly some purported objections against Tarski’s truth condition are stated and two important presuppositions of Tarski’s truth condition are analyzed. Thirdly TTC is enlarged in different ways as to incorporate the preconditions explicitly. Finally in the fourth section it will be shown how the revised T-conditions solve different versions of the (...) Liar. All of these topics are discussed in much more detail in my forthcoming book, Chapter 7. (shrink)
The first part of the papaer contains desiderata for a realistic epistemic system as opposed to idealistic ones. One of the main characteristics of idealistic epistemic systems is their deductive infallibility or deductive omniscience. The system presented avoids deductive infallibility though having a strong concept of knowledge. The second part contains the theorems of the system. The system is detailed in so far as it distinguishes between two concepts of belief and one of assumption and interrelates them to the concept (...) of knowledge. Though all concepts satisfy certain consistency criteria the strongest ones hold for the concept of knowledge; whereas a belief in or a assumption (assertion) of a proposition which has inconsistent consequences (not known or believed or assumed by the believer or assumer) does not entail the commitment of believing in (or assuming of) an explicit contradiction. Moreover the system contains a lot of distinctions and details concerning propositions with a second person involved like "a knows that b knows whether p is the case" etc. The third part of the paper contains the semantics of the system which consists of many-valued truth-tables. Since the matrices are finite the system is consistent and decidable. (shrink)
Jaakko Hintikka's concept of belief (aBp) as presented in his Knowledge and Belief is such that in his epistemic logic aKp —> aBp is a thesis. This concept (B-belief) is one important kind of belief and can be contrasted with a different concept of belief (G-belief, denoted by 'aOp') not discussed in Hintikka's book. It is to some extent opposite to the one above in the sense that it is knowledge-exclusive, whereas Hintikka's is knowledge-inclusive. This is shown by the thesis (...) aKp —> —laGp or aGp —> —laKp. My thesis is that this kind of belief is used as the belief in scientific hypothesis and as religious belief. Both G-belief and B-belief are applied to examples from physics and religion and consistency criteria are discussed for either concept. (shrink)
The present article shows that there are consistent and decidable manyvalued systems of propositional logic which satisfy two or all the three criteria for non-trivial inconsistent theories by da Costa . The weaker one of these paraconsistent system is also able to avoid a series of paradoxes which come up when classical logic is applied to empirical sciences. These paraconsistent systems are based on a 6-valued system of propositional logic for avoiding difficulties in several domains of empirical science ).