Modern belief revision theory is based to a large extent on partial meet contraction that was introduced in the seminal article by Carlos Alchourrón, Peter Gärdenfors, and David Makinson that appeared in 1985. In the same year, Alchourrón and Makinson published a significantly different approach to the same problem, called safe contraction. Since then, safe contraction has received much less attention than partial meet contraction. The present paper summarizes the current state of knowledge on safe contraction, provides some new results (...) and offers a list of unsolved problems that are in need of investigation. (shrink)

A discussion of the connections and differences between completeness and representation theorems in logic, with examples drawn from classical and modal logic, the logic of friendliness, and nonmonotonic reasoning.

Resumen Como es muy conocido, Frege afirmó que la expresión ‘el concepto caballo’ se refiere a un objeto y no a un concepto. En este artículo, en primer lugar, mostramos cómo hay algunos barruntos de esta paradoja en textos anteriores a 1891. En segundo lugar, revisamos algunos argumentos que defienden que con el término ‘el concepto caballo’ Frege se refería a la extensión del mencionado concepto. Por último, sostendremos que, aun cuando el concepto caballo sea dicha extensión, es muy poco (...) lo que sabemos de su naturaleza. Esto último se debe a la forma fragmentaria en que Frege introduce las extensiones de concepto en los Grundgesetze y en ensayos previos.As is well known, Frege stated that the expression ‘the concept horse’ refers to an object and not to a concept. In this article we firstly show how there are some hints of this paradox in texts prior to 1891. Secondly we review some arguments given in the literature to hold that with ‘the concept horse’ Frege referred to the extension of the mentioned concept. Finally, we argue that, even if the concept horse is such an extension, we still know very little about its nature, given the fragmentary way in which Frege introduces the extensions of concepts in Grundgesetze and in previous essays. (shrink)

According to Wittgenstein, mathematical propositions are rules of grammar, that is, conventions, or implications of conventions. So his position can be regarded as a form of conventionalism. However, mathematical conventionalism is widely thought to be untenable due to objections presented by Quine, Dummett and Crispin Wright. It has also been argued that only an implausibly radical form of conventionalism could withstand the critical implications of Wittgenstein’s rule-following considerations. In this article I discuss those objections to conventionalism and argue that none (...) of them is convincing. (shrink)

Gottfried Gabriel is interviewed by Todor Polimenov about the relationship between analytic and continental philosophy.

What is the relation of logic to thinking? My dissertation offers a new argument for the claim that logic is constitutive of thinking in the following sense: representational activity counts as thinking only if it manifests sensitivity to logical rules. In short, thinking has to be minimally logical. An account of thinking has to allow for our freedom to question or revise our commitments – even seemingly obvious conceptual connections – without loss of understanding. This freedom, I argue, requires that (...) thinkers have general abilities to respond to support and tension among their thoughts. And these abilities are constituted by following logical rules. So thinkers have to follow logical rules. But there isn’t just one correct logic for thinking. I show that my view is consistent with logical pluralism: there are a range of correct logics, any one of which a thinker might follow. A logic for thinking does, however, have to contain certain minimal principles: Modus Ponens and Non-Contradiction, and perhaps others. We follow logical rules by exercising logical capacities, which display a distinctive first-person/third-person asymmetry: a subject can find the instances of a rule compelling without seeing them as instances of a rule. As a result, there are two limits on illogical thinking. First, thinkers have to tend to find instances of logical rules compelling. Second, thinkers can’t think in obviously illogical ways. So thinking has to be logical – but not perfectly so. When we try to think, but fail, we produce nonsense. But our failures to think are often subjectively indistinguishable from thinking. To explain how this occurs, I offer an account of nonsense. To be under the illusion that some nonsense makes sense is to enter a pretence that the nonsense is meaningful. Our use of nonsense within the pretence relies on the role of logical form in understanding. Finally, while the normativity of logic doesn’t fall directly out of logical constitutivism, it’s possible to build an attractive account of logical normativity which has logical constitutivism as an integral part. I argue that thinking is necessary for human flourishing, and that this is the source of logical normativity. (shrink)

Mathematicians often speak of conjectures, yet unproved, as probable or well-confirmed by evidence. The Riemann Hypothesis, for example, is widely believed to be almost certainly true. There seems no initial reason to distinguish such probability from the same notion in empirical science. Yet it is hard to see how there could be probabilistic relations between the necessary truths of pure mathematics. The existence of such logical relations, short of certainty, is defended using the theory of logical probability (or objective Bayesianism (...) or non-deductive logic), and some detailed examples of its use in mathematics surveyed. Examples of inductive reasoning in experimental mathematics are given and it is argued that the problem of induction is best appreciated in the mathematical case. (shrink)

CAT4 is proposed as a general method for representing information, enabling a powerful programming method for large-scale information systems. It enables generalised machine learning, software automation and novel AI capabilities. It is based on a special type of relation called CAT4, which is interpreted to provide a semantic representation. This is Part 2 of a five-part introduction. The focus here is on defining key mathematical properties of CAT2, identifying the topology and defining essential functions over a coordinate system. The analysis (...) is from first principles. This develops on from the axioms introduced in Part 1. The interpretation of fact networks is introduced in Part 3, and the full application to semantic theory comes in Part 4, where we introduce general functions, including the language interpretation or linguistic functions. In Part 5, we turn to software design considerations, to show how files, indexes, functions and screens can be defined to implement a CAT4 system efficiently. (shrink)

CAT4 is proposed as a general method for representing information, enabling a powerful programming method for large-scale information systems. It enables generalised machine learning, software automation and novel AI capabilities. It is based on a special type of relation called CAT4, which is interpreted to provide a semantic representation. This is Part 1 of a five-part introduction. The focus here is on defining the key mathematical structures first, and presenting the semantic-database application in subsequent Parts. We focus in Part 1 (...) on general axioms for the structures, and introduce key concepts. Part 2 analyses the CAT2 sub-relation of CAT4 in more detail. The interpretation of fact networks is introduced in Part 3, where we turn to interpreting semantics. We start with examples of relational and graph databases, with methods to translate them into CAT3 networks, with the aim of retaining the meaning of information. The full application to semantic theory comes in Part 4, where we introduce general functions, including the language interpretation or linguistic functions. The representation of linear symbolic languages, including natural languages and formal symbolic languages, is a function that CAT4 is uniquely suited to. In Part 5, we turn to software design considerations, to show how files, indexes, functions and screens can be defined to implement a CAT4 system efficiently. (shrink)

The pragmatic notion of assertion has an important inferential role in logic. There are also many notational forms to express assertions in logical systems. This paper reviews, compares and analyses languages with signs for assertions, including explicit signs such as Frege’s and Dalla Pozza’s logical systems and implicit signs with no specific sign for assertion, such as Peirce’s algebraic and graphical logics and the recent modification of the latter termed Assertive Graphs. We identify and discuss the main ‘points’ of these (...) notations on the logical representation of assertions, and evaluate their systems from the perspective of the philosophy of logical notations. Pragmatic assertions turn out to be useful in providing intended interpretations of a variety of logical systems. (shrink)

CAT4 is proposed as a general method for representing information, enabling a powerful programming method for large-scale information systems. It enables generalised machine learning, software automation and novel AI capabilities. This is Part 3 of a five-part introduction. The focus here is on explaining the semantic model for CAT4. Points in CAT4 graphs represent facts. We introduce all the formal (data) elements used in the classic semantic model: sense or intension (1st and 2nd joins), reference (3rd join), functions (4th join), (...) time and truth (logical fields), and symbolic content (name/value fields). Concepts are introduced through examples alternating with theoretical discussion. Some concepts are assumed from Part 1 and 2, but key ideas are re-introduced. The purpose is to explain the CAT4 interpretation, and why the data structure and CAT4 axioms have been chosen: to make the semantic model consistent and complete. We start with methods to translate information from database tables into graph DBs and into CAT4. We conclude with a method for translating natural language into CAT4. We conclude with a comparison of the system with an advanced semantic logic, the hyper-intensional logic TIL, which also aims to translate NL into a logical calculus. The CAT4 Natural Language Translator is discussed in further detail in Part 4, when we introduce functions more formally. Part 5 discusses software design considerations. (shrink)

In British and American anthropological literature, the ethnology of Central and Eastern European countries has shared in the plight of descriptions of this part of the world: it was seen as exotic, foreign, remote, a backwater, focused on sideline problems and situated on the periphery of this field of science. This state of affairs has been the case since at least the beginning of the Cold War as the descriptions of the national characters of Eastern Bloc communities, drafted by American (...) scholars. The ethnography of these countries was automatically aligned with the same categories of description which were applied to the characteristics of these communities. This was, in part, an effect of entirely different research traditions in the subject matter, objectives and methods of these remote parts of the science. The differences of ’cultural wholes’ did have a decisive impact on the image of ethnology. Like all these communities, Polish ethnology was perceived as a homogeneous whole, which it never was. (shrink)

An overview of what Frege accomplishes in Part II of Grundgesetze, which contains proofs of axioms for arithmetic and several additional results concerning the finite, the infinite, and the relationship between these notions. One might think of this paper as an extremely compressed form of Part II of my book Reading Frege's Grundgesetze.

A speculative investigation of how Frege's logical views change between Begriffsschrift and Grundgesetze and how this might have affected the formal development of logicism.

The subject of this paper is the epistemology of identity: a general theory of knowledge, evidence and justification for the claim that one thing is identical to another. Although identity figures significantly in our epistemic lives, this is a topic that, to the best of my knowledge, has gone entirely unexplored. Initial attempts to integrate such an epistemology into existing theories of evidence---many of which are tailor-made for contingent propositions---are confounded by the necessity of identity. I defend a restricted form (...) of skepticism according to which the only knowable identity claims are trivial. (shrink)

This thesis will survey several prominent approaches to analysing causation, discuss their differences and similarities, and look at a number of problems which are common to all of them. I will be arguing for the following claims about how we should approach the process of analysing causation. Firstly, I will be arguing that a reductive analysis is desirable, since if we can reductively analyse causation in terms of something empirically accessible, we can explain how it is possible to know anything (...) about causation. I will argue that to reductively analyse causation is to find out what kind of facts ground causal facts. Secondly, I will argue, following Hall and Strevens, that there are two kinds of causation, causal difference making and causal influence. This two-tiered approach explains the cases where we are tempted to ascribe conflicting characteristics to our concept of causation. Thirdly, I will argue that causal influence grounds causal difference making and that it does so necessarily. That the grounding relation holds necessarily is important for defending the two-tiered approach against the objection that it would yield a disjunctive account. (shrink)

There can be no doubt about the value of Frege's contributions to the philosophy of mathematics. First, he invented quantification theory and this was the first step toward making precise the notion of a purely logical deduction. Secondly, he was the first to publish a logical analysis of the ancestral R* of a relation R, which yields a definition of R* in second-order logic.1 Only a narrow and arid conception of philosophy would exclude these two achievements. Thirdly and very importantly, (...) the discussion in §§58-60 of the G r u n d l a g e n defends a conception of mathematical existence, to be found in Cantor (1883) and later in the writings of Dedekind and Hilbert, by basing it upon considerations about meaning which have general application, outside mathematics.2.. (shrink)

This paper is divided in five sections. Section 11.1 sketches the history of the distinction between speech act with negative content and negated speech act, and gives a general dynamic interpretation for negated speech act. “Downdate semantics” for AGM contraction is introduced in Section 11.2. Relying on semantically interpreted contraction, Section 11.3 develops the dynamic semantics for constative and directive speech acts, and their external negations. The expressive completeness for the formal variants of natural language utterances, none of which is (...) a retraction, has been proved in Section 11.4. The last section gives a laconic answer to the question posed in the title of the paper. (shrink)

Provides a survey of the development of speech act theory from Aristotle through Reid and Peirce to Edmund Husserl, Anton Marty, Johannes Daubert, Adolf Reinach, and finally to Austin and Searle. A special role is played by Husserl's theory of objectifying acts (meaning, roughly, acts of naming or stating) and of the efforts by his followers to extend this theory to cover phenomena such as questioning and commanding. These efforts culminated in the work of Adolf Reinach, who developed the first (...) systematic theory of speech acts in connection with his monograph of 1913 on “The A Priori Foundations of the Civil Law”. (shrink)

Cognitive sciences are grouped together according to their substantial disciplines such as neurobiology, psychology, linguistics and many others. From more than ten years a search has been undertaken for the best fitting cognitive research method, that does not influence the scientific output. More recently attention has been turned to systems which might operate through their dynamic aspect, called the dynamic approach. Their great advantage is to see the old linguistic axioms such as connectivity in a new way.

Este artículo tiene como finalidad estudiar la noción de aserción en dos obras del siglo XVII francés: La Logique ou l’art de penser, de Antoine Arnauld y Pierre Nicole, y la Grammaire générale et raisonnée, de Antoine Arnauld y Claude Lancelot. Se ha dividido el artículo en dos apartados dedicados respectivamente a la concepción de Port-Royal acerca del juicio, y a la teoría del verbo. A lo largo de la reflexión en torno a estos importantes conceptos en la teoría del (...) lenguaje de Port-Royal, pretendemos probar que sus autores efectuaron la distinción entre contenido proposicional y actitud proposicional antes de que Frege la estableciera de forma sólida y definitiva. The present paper sets out to examine the notion of assertion within two French 17th century works: Antoine Arnauld and Pierre Nicole’s La Logique ou l’art de penser, and Antoine Arnauld and Claude Lancelot’s Grammaire générale et raisonnée. This article has been divided into two sections. The first section is devoted to the Port-Royalian doctrine about judgment; the second section analyzes the theory of verb. On our account of these important notions of Port-Royal’s theory of language, we intend to prove that its authors had made out the distinction between propositional content and propositional attitude before Frege could set it forth in a solid and definite way. (shrink)

This is the first part of the essay devoted to the story of logicism, in particular to its Fregean version. Reviewing the classical period of Fregean studies, we first point out some critical moments of Frege‘s argumentation in the Grundla­gen, in order to be able later to differentiate between its salvageable and defec­tive features. We work on the presumption that there are no easy, catego­rical an­swers to questions like “Is logicism dead?“: Wittgenstein’s cri­tique of the foundational program as well as (...) the remarkable neo-Fregean dis­cov­eries of Boolos and Wright have to be confronted with the effects which the logi­cistic idea actually had on logico­matemati­cal practice. But that is another story, a sequel to this es­say, the purpose of which is systematic rather than criti­cal. (shrink)

Reviewing the beginnings and the further development of logicistic idea I am mainly focusing on the tradition of Frege and Russell, i. e. the tradition which was in the closest relationship with the enterprise of modern logic. I am trying to assess its connections to other „logistic“ programs such as Dedekind’s structuralism or Peano‘s axiomatism, to underline its specific features and the share in the success of modern logical semantics, including both its substantial contribution and limitations.

Quine claimed that to be is is to be a value of a bound variable. In the paper we assume that this claim contains an important philosophical insight and investigate its background. It is argued that there are two dimensions involved in Quine’s slogan: (i) the distinction between existing and non-existing objects and (ii) the question of the systematic ambiguity of being that can be traced back to Aristotle. At the first sight it is tempting to construe Quine’s criterion according (...) to the first dimension. In this light it appears as an anti-Meinongian device and the Russelian roots of Quine’s philosophy make this interpretation prima facie plausible. However, it is argued that it is the anti-Aristotelian line which is dominant in Quine’s philosophy, and which is ontologically much more interesting. (shrink)

I examine the difficulties that several philosophers of language are liable to encounter in their attempts to provide an account of the connection between truth and assertion. I then attempt to provide an account of this connection. The analysis is concerned chiefly with difficulties which consist in elucidating the conceptual connection between truth and assertion in a way that respects certain linguistic intuitions while at the same time rendering the concept of truth amenable to a semantic interpretation. The proposed view (...) suggests one way in which we might go about meeting the theoretical demands implicit in addressing this concern, among others, demonstrating the extent to which a theory of truth should be regarded as belonging to the province of epistemology. Insofar as semantical considerations figure into such a theory, a more systematic investigation of the interface between epistemology and natural language semantics is recommended. The solution to many problems at this interface, I argue, lay in an analysis of judgment. (shrink)

way on the information available in the contexts in which they are used, it’s not surprising that there is a minor but growing industry of work in semantics and the philosophy of language concerned with the precise nature of the context-dependency of epistemically modalized sentences. Take, for instance, an epistemic might-claim like..

The paper outlines the analysis of certain question types in the Commitment Space framework, as presented in Krifka (2015). The two basic ideas are: Assertions and most questions involve commitments of speaker and addressee to the truth of a proposition, and questions consist in restricting the continuation of the conversation to answers to the question. The main focus is on breadth, not depth and the detailed comparison with alternative approaches, and on semantic modelling, not on the syntactic and prosodic realizations. (...) Topics are polar questions and their bias, alternative questions, constituent questions, high negation in questions, declarative questions, root vs. embedded questions, and deliberative questions. (shrink)

Mathematics in the 19th century underwent explosive development. The discussion among philosophers was motivated by new results which conflicted with Kant’s very influential conception. One of the most important areas which lead to the meeting of philosophy and mathematics was a rigorous account of the infinitesimal calculus. In his article the author shows that considerations of this type found in Bolzano and Frege are important not only for the overcoming of the Kantian conception, but as for what we today call (...) the linguistic turn. (shrink)

The identity concept developed in the Homotopy Type theory supports an analysis of Frege's famous Venus example, which explains how empirical evidences justify judgements about identities. In the context of this analysis we consider the traditional distinction between the extension and the intension of concepts as it appears in HoTT, discuss an ontological significance of this distinction and, finally, provide a homotopical reconstruction of a basic kinematic scheme, which is used in the Classical Mechanics, and discuss its relevance in the (...) Quantum Mechanics. (shrink)

This is our journal for developing Deduction Theory and studying Deep Learning and Artificial intelligence. Deduction Theory is a Theory of Deducing World’s Relativity by Information Coupling and Asymmetry. We focus on information processing, see intelligence as an information structure that relatively close object-oriented, probability-oriented, unsupervised learning, relativity information processing and massive automated information processing. We see deep learning and machine learning as an attempt to make all types of information processing relatively close to probability information processing. We will discuss (...) about how to understand Deep Learning and Artificial intelligence and why Deep Learning is shown better performance than the other methods by metaphysical logic. (shrink)

So selbstverständlich es klingt, vom Geist, der Psyche oder auch der Seele eines Menschen zu reden, und so vertraut uns wissenschaftliche Disziplinen sind, die sich philosophisch oder empirisch damit beschäftigen, so schwer fällt es, ein einheitliches Merkmale dafür anzugeben, wann etwas ein psychisches Phänomen ist. Viele der potentiellen Merkmale decken eben nur einen Teil des Spektrums dessen ab, was wir gewöhnlich als psychisch bezeichnen würden, und sind damit bestenfalls hinreichende, aber sicher keine notwendigen Bedingungen des Psychischen. Im Mittelpunkt des folgenden (...) Artikels wird dagegen ein Merkmal stehen, von dem feststeht, daß es nicht hinreichend ist, von dem man aber vermuten kann, es sei zumindest notwendig: die Individualität psychischer Phänomene. Die Frage, mit der ich mich beschäftigen werde, ist, ob sich diese Vermutung mit Bezug auf eine Grnppe paradigmatisch psychischer Phänomene aufrecht erhalten läßt, die intentionalen Einstellungen. (shrink)

Logic and philosophy of science share a long history, though contacts have gone through ups and downs. This paper is a brief survey of some major themes in logical studies of empirical theories, including links to computer science and current studies of rational agency. The survey has no new results: we just try to make some things into common knowledge.