In the paper, original formal-logical conception of syntactic and semantic: intensional and extensional senses of expressions of any language L is outlined. Syntax and bi-level intensional and extensional semantics of language L are characterized categorically: in the spirit of some Husserl’s ideas of pure grammar, Leśniewski-Ajukiewicz’s theory syntactic/semantic categories and in accordance with Frege’s ontological canons, Bocheński’s famous motto—syntax mirrors ontology and some ideas of Suszko: language should be a linguistic scheme of ontological reality and simultaneously a tool of its (...) cognition. In the logical conception of language L, its expressions should satisfy some general conditions of language adequacy. The adequacy ensures their unambiguous syntactic and semantic senses and mutual, syntactic, and semantic compatibility, correspondence guaranteed by the acceptance of a postulate of categorial compatibility syntactic and semantic categories of expressions of L. From this postulate, three principles of compositionality follow: one syntactic and two semantic already known to Frege. They are treated as conditions of homomorphism partial algebra of L into algebraic models of L: syntactic, intensional, and extensional. In the paper, they are applied to some expressions with quantifiers. Language adequacy connected with the logical senses described in the logical conception of language L is, of course, an idealization, but only expressions with high degrees of precision of their senses, after due justification, may become theorems of science. (shrink)

Important aspects of its philosophical basis, and its significance for the foundations of mathematics, appeared in The Foundations of Mathematics (FA, 1884). Six years later, at the beginning of the 1890s, Frege published three articles that mark significant changes in his conception: "Function and Concept" (FC, 1891), "On Sense and Reference" (SR, 1892) and "Concept and Object" (1892). Notable among these changes are: (a) The systematic distinction between the sense and the reference of expressions as two separate ingredients (...) of their meaning. (b) The extension and generalization of the notion of function to include the conception of concepts and relations as functions to truth-values, and the corresponding conception of the two truth-values as objects. These changes were immediately incorporated in the mature, authoritative exposition of his logic in his magnum opus: Basic Laws of Arithmetic (BL), whose first volume appeared in 1893. (shrink)

This paper is about the efforts the norwegian psychologist Jan Smedslund made in analyzing and checking philosophically his theory called ‘Psycho-logic’. I am going to reconstruct and discuss the debates between Smedslund and several critics, which have been going on since about 1978, mainly in the “Scandinavian Journal of Psychology”. A result will be that the kind of modal logics Smedslund uses — a type with realistic semantics and epistemology — is not the proper one for the analysis of (...) ‘Psycho-logic’. (shrink)

Considering the persisting disagreement between the common sense philosophers and the sceptics, it seems that they are faced with a deep epistemic disagreement. Taking stock from Wittgenstein’s On Certainty, one generally thinks that deep epistemic disagreements cannot be rationally resolved. Hinge epistemology, inherited from Wittgenstein, is also considered as an illuminating detour to understand common sense epistemology. But is there really a deep epistemic disagreement between the common sense philosophers and the sceptics? Could it not be considered (...) that they share a common background? If so, is the rational resolution of their disagreement logically possible? What rational means can common sense use to convince someone of the privileged status of an epistemic principle? Relying on Reid’s, Alston’s and Lynch’s arguments, I show that common sense epistemology is a more promising approach than hinge epistemology, because it is driven by an optimism about reason in the solving of deep epistemic disagreements. (shrink)

Logic, considered as a technical discipline inaugurated by Aristotle and typically represented by the variety of the modern logical calculi, constitutes a clarification and refinement of a conviction and practice present in common sense, that is, the fact that humans believe that truth can be acquired not only by immediate evidence, but also by means of arguments. As a first step logic can be seen as a “descriptive” record of the main forms of the arguments present in (...) common sense, but the fact that some of these patterns can actually allow for the derivation of false consequences from true premises imposes the task of making explicit what patterns correspond to a “correct reasoning” and what not. At this point logic appears endowed with a “normative” characteristic. This amounts to saying that logical calculi are intended to adequately mirror the intuitive notion of “logical consequence” and in this sense they cannot be totally arbitrary or conventional, but must satisfy certain basic requirements such as the conditions of soundness and of semantic completeness. In such a way they are “judged” according to the fundamental requirements present at the level of common sense and appear as “idealizations” of the kinds of reasoning practiced in common sense. For this reason also several kinds of logical calculi are fully justified since they make explicit in an idealized form the concrete ways of reasoning that are imposed by the particular domain of reference of the discipline in which they are used and which are basically recognized in common sense. (shrink)

John McCarthy, Stanford University Logical AI (artificial intelligence) is based on programs that represent facts about the world in languages of mathematical logic and decide what actions will achieve goals by logical reasoning. A lot has been accomplished with logic as is.

The present study of sense and reference in the logic of Frege represents the first fruits of several years of dealing with the work of this great German logician. In the preparation of this work, which was presented as a dissertation to the Faculty of Philosophy of the Friedrich-Alexander University in Erlangen/Nuremberg, assistance came from many quarters. lowe most to Professor R. Zocher, who directed this dissertation with understanding counsel and unflagging interest. I must also thank Professor P. (...) Lorenzen, whose courses and seminars provided more inspiration than might be immediately apparent in the book. Professor W. Britzelmayr of Munich was so kind as to provide copies of important fragments of Frege's works. These texts are reproduced with the permission of Professor H. Hermes, Director of the 'Institut fUr mathematische Logik und Grund lagenforschung' in Munster, where Frege's works and letters are being prepared for publication. The preparation of this work was greatly facilitated by a two-year grant from the Fritz Thyssen Foundation. CHRISTIAN THIEL Nuremberg, February 1965 v TRANSLATOR'S NOTE In the difficult matter of Fregean terminology we have taken Ignacio Angelelli's translation of Two Soviet Studies on Frege as the model. Both Professor Angelelli and Dr. Thiel have been so kind as to read over the translation before publication. (shrink)

What is involved in the meaning of our expressions? Frege suggested that there is an aspect of an expression.

The notion of logical construction was used by Bertrand Russell in the early 20th century, which originally comes from A. N. Whitehead. Russell said that matter as a mind-independent thing can only be known by description. He also argued that matter is a logical construction of sense-data. However, this leads to an incoherent view of the direct or indirect connection between a mind and the external world. The problem examining is whether a collapsing house is a logical construction of (...) the sense-data of rumbling sounds and collapsing shapes. Using Russell's writings between 1911 and 1918, I will analyze how Russell characterized logical constructions. Finally, I will show Russell’s view about the relation of logical constructions to matter and sense-data. A careful interpretation of Russell's thoughts shows that the contents of the statements of the physical world are not constructions being equivalent to the contents of the sense-datum statements. (shrink)

In this paper, I revisit Frege's theory of sense and reference in the constructive setting of the meaning explanations of type theory, extending and sharpening a program–value analysis of sense and reference proposed by Martin-Löf building on previous work of Dummett. I propose a computational identity criterion for senses and argue that it validates what I see as the most plausible interpretation of Frege's equipollence principle for both sentences and singular terms. Before doing so, I examine Frege's implementation (...) of his theory of sense and reference in the logical framework of Grundgesetze, his doctrine of truth values, and views on sameness of sense as equipollence of assertions. (shrink)

Gottlob Frege's brief article Uber Sinn und Bedeutung (On Sense and Reference) has come to be seen, in the century since its publication in 1892, as one of the seminal texts of analytic philosophy. It, along with the rest of Frege's writings on logic and mathematics, came to mark out a whole new domain of inquiry and to set the agenda for it. This volume bears witness to the continuing importance and influence of that agenda. It contains original (...) papers written by leading Frege scholars for the conference held in 1992 in Karlovy Vary to celebrate the centenary of the publication of Frege's essay. The 14 essays show how the questions Frege discusses in that essay connect intimately with issues much debated in current philosophy of language and philosophy of mind. (shrink)

Contributing to the debate between referentialist and predicativist accounts of the semantics of proper names, this paper partly endorses a recent trend to reject unitary accounts of their semantics. It does so by restoring a Fregean version of the variety of use account. It criticizes alternative variety of use accounts for not clearly distinguishing pragmatic, syntactic, and semantic issues and argues that, once these are distinguished, the necessity of accepting that names have a variety of uses, and are sometimes logical (...) singular terms and at others logical predicates shows that Frege’s claim, that we should recognize that names have both reference and sense, is vindicated. (shrink)

In his Logical Investigations Edmund Husserl criticizes John Stuart Mill’s account of meaning as connotation, especially Mill’s failure to separate the distinction between connotative and non-connotative names from the distinction between the meaningful and the meaningless. According to Husserl, both connotative and non-connotative names have meaning or “signification”, that is, what Gottlob Frege calls the sense (“Sinn”) of an expression. The distinction between connotative and non-connotative names is a distinction between two kinds of meaning (or sense), attributive and (...) non-attributive meaning (“attributive und nicht-attributive Bedeutung”). Attributive (connotative) names denote (refer to) objects through their attributes, whereas a non-attributive name means a thing directly (“direkt”). In this paper I examine the concepts of attributive and non-attributive meaning by means of the semiotic theory of Charles S. Peirce, and compare Peirce’s account with the views of Frege, Husserl, Alexius Meinong, and David Kaplan and Gareth Evans. (shrink)

Sense, Reference, and Philosophy develops the far-reaching consequences for philosophy of adopting non-Fregean intensionalism, showing that long-standing problems in the philosophy of language, and indeed other areas, that appeared intractable can now be solved. Katz proceeds to examine some of those problems in this new light, including the problem of names, natural kind terms, the Liar Paradox, the distinction between logical and extra-logical vocabulary, and the Raven paradox. In each case, a non-Fregean intentionalism provides a philosophically more satisfying solution.

The concept of tact has so far received only little theoretical attention. The present article suggests three levels on which the idea of tact may be approached: (1) The epistemological problem: the etymology of the term ?tact? is taken seriously, namely its relation to the sense of touch and tactility. An analysis of the position of touch in the ranking of the five senses according to various parameters is shown to be highly relevant to the understanding of the idea (...) of tact. (2) The logical problem: tact is described as a skill which cannot be exhausted in the knowledge of principles or general rules. Like ?judgment? it is concerned with the particular, with sensitivity (analogical to that of the sense of touch) to the uniqueness of a human situation. (3) The ethical problem: tact is shown to lie between ethics and etiquette, that is to say it is more than just a rule of politeness or good manners, but it is ?less? than a fully fledged moral duty or principle. Its position between the obligatory and the merely conventional opens the way to characterize it as supererogatory. (shrink)

We show that, contrary to conventional wisdom, Frege’s distinction between sense and reference does not reconcile a classical logic of identity with apparent counterexamples to it involving proper names embedded under propositional attitude verbs.

Philosophers have not been sceptical only about metaphysics or religious beliefs. There are a great number of other beliefs generally held which they have had at least as much difficulty in justifying, and in the present article I ask questions as to the right philosophical attitude to these beliefs in cases where to our everyday thought they seem so obvious as to be a matter of the most ordinary common sense. A vast number of propositions go beyond what is (...) merely empirical and cannot be seen to be logically necessary but are still believed by everybody in their daily life. Into this class fall propositions about physical things, other human minds and even propositions about one's own past experiences based on memory, for we are not now ‘observing’ our past. The phenomenalist does not escape the difficulty about physical things, for he reduces physical object propositions, in so far as true, not merely to propositions about his own actual experience but to propositions about the experiences of other human beings in general under certain conditions, and he cannot either observe or logically prove what the experiences of other people are or what even his own would be under conditions which have not yet been fulfilled. What is the philosopher to say about such propositions? Even Moore, who insisted so strongly that we knew them, admitted that we did not know how we knew them. The claim which a religious man makes to a justified belief that is neither a matter of purely empirical perception nor formally provable is indeed by no means peculiar to the religious. It is made de facto by everybody in his senses, whether or not he realizes that he is doing so. There is indeed a difference: while everyone believes in the existence of other human beings and in the possibility of making some probable predictions about the future from the past, not everybody holds religious beliefs, and although this does not necessarily invalidate the claim it obviously weakens it. (shrink)

Gilbert Ryle and a number of other philosophers have argued that Descartes’ claim his senses could always deceive him is false. Ryle’s argument is the well-known ‘counterfeit coins’ argument. A similar argument, featuring forged paintings, has been advanced by Jay Rosenberg. Both Ryle’s and Rosenberg’s arguments are refutations by logical analogy. In this paper, their arguments are exposed and reconstructed, and it is shown and how and why their refutations by logical analogy fail. It is then noted that, even so, (...) they could be right about the invalidity of Descartes’ argument. A close examination of Descartes’ argument, however, shows that there is nothing wrong with it. (shrink)

In this paper we give some formal examples of ideas developed by Penco in two papers on the tension inside Frege's notion of sense (see Penco 2003). The paper attempts to compose the tension between semantic and cognitive aspects of sense, through the idea of sense as proof or procedure – not as an alternative to the idea of sense as truth condition, but as complementary to it (as it happens sometimes in the old tradition of (...) procedural semantics). (shrink)

A foundationalist account of the justification of our empirical beliefs is committed to the following two claims: (1) Sense experience is a source of justification. (2) Some empirical beliefs are basic: justified without receiving their justification from any other beliefs. In this paper, I will defend each of these claims against an objection. The objection to (1) that I will discuss is due to Donald Davidson. He writes: The relation between a sensation and a belief cannot be logical, since (...) sensations are not beliefs or other propositional attitudes. What then is the relation? The answer is, I think, obvious: the relation is causal. Sensations cause some beliefs and in this sense are the basis or ground of those beliefs. But a causal explanation of a belief does not show how or why the belief is justified. [1] There are two important thoughts in this passage. The first of these is explicitly expressed, the second implied: (3) Sense-experiential states are devoid of propositional content. (4) Necessarily, if a mental state can play the role of a justifier, it has propositional content. (3) and (4) entail that a sense-experiential state cannot play the role of a justifier. If that is true, then (1) is false. This, in any case, seems to me to be Davidson's argument. In response to it, I accept (4) but reject (3). This is an unusual move for foundationalists, who tend to accept (3) and deny (4). Nevertheless, it is what I take to be the right move. (shrink)

The article presents a concept apparatus of identifying and eliminating non-compositionality on the basis of intended sense reconstruction. First, two types ofnon-compositionality are delineated: pragmatically adoptable and logical. Thenon-compositionality ofthe first type has its source in underspecification of the meaning of an expression components, which is connected with non-expressible context-pragmatic conditions ofthesituation of an expression. The variants ofsuch non-compositionality are various, nevertheless allof them can be adopted with logical and semantic means. Non-compositionality ofthe secondtype is linked to the cyclic (...) references which occur during the realisation ofthe procedure of defining the meaning. Sucha procedure is regarded as a semantic program which is capable of calculating the meaning of an expression with semantic and context-pragmatic parameters being given. The main question: howthe agents communication recognise thefactthatthe language expressions they generated are not adequate in regards of those mental representa- tionswhich constitute intended sense, particularly in the cases of non-compositionality. To answer this question the way of reconstructing intended sense is described. It includes differentiation of minimal and full senses of expression, and presupposes juxtaposing of context-pragmatic conditions of a speaker situation with the same conditions an addressee situation. If differences are uncovered which would make it impossible to achieve adequate understanding,then the parameters ofa speaker's situation are verbalised and stop beingnon-expressible turninginto obvious conditions ofthe stated. In the case of pragmatically adopted non-compositionality, full verbalisation of context-pragmatic conditions leads to obtaining full compositional meaning, which does not depend on a situation anymore. If it turns out, that logical compositionality depends on context-pragmatic conditions, then, depending on the aim of communication, it maybe localised and eliminated. (shrink)

This paper argues that institutions are higher-level autonomous systems enacted by patterns of participatory sense-making. Therefore, unlike in the standard equilibrium theory, institutions are not themselves thought of as behavioural patterns. Instead, they are problem domains that these patterns have brought forth. Moreover, these are not merely any patterns, but only those devoted to maintaining a specific strategy of problem solving, called the strategy of ‘letting be’. The latter refers to, following Hanne de Jaegher, a balance between underdetermination and (...) overdetermination of individual behaviour by a collective. Such an understanding of institutions becomes an option once a hybrid ‘equilibrium + rules’ theory of institutions, such as the one proposed by Frank Hindriks, is supplemented with insights from enactivism. In this light, drawing a connection between these two areas is the additional, meta-theoretical goal of this paper. This connection is beneficial, I argue, in particular since it allows for a satisfactory, in-depth account of the normative character of institutions as well as their local character. (shrink)

Perfect for students with no background in logic or philosophy, Simple Formal Logic provides a full system of logic adequate to handle everyday and philosophical reasoning. By keeping out artificial techniques that aren’t natural to our everyday thinking process, Simple Formal Logic trains students to think through formal logical arguments for themselves, ingraining in them the habits of sound reasoning. Simple Formal Logic features: a companion website with abundant exercise worksheets, study supplements (including flashcards for (...) symbolizations and for deduction rules), and instructor’s manual two levels of exercises for beginning and more advanced students a glossary of terms, abbreviations and symbols. This book arose out of a popular course that the author has taught to all types of undergraduate students at Loyola University Chicago. He teaches formal logic without the artificial methods–methods that often seek to solve farfetched logical problems without any connection to everyday and philosophical argumentation. The result is a book that teaches easy and more intuitive ways of grappling with formal logic–and is intended as a rigorous yet easy-to-follow first course in logical thinking for philosophy majors and non-philosophy majors alike. (shrink)

In this paper, I will discuss a well-known oscillation in Frege’s conception of sense. My point is only partially concerned with his two different criteria of sense identity, and touches upon a more specific point: what happens if we apply Frege’s intuitive criterion for the difference of thoughts to logically equivalent sentences? I will try to make a schematic argument here that will preempt any endeavor to make Frege more coherent than he really is. In sections A and (...) B, I will present two alternative Fregean ways to treat the sense of logically equivalent sentences. Frege really oscillated between two alternative conceptions of sense, and his inability to detect the contrast between the two alternative conceptions is partly due to his strong conception of rationality. To apply the criterion of difference of thoughts to logical matters, we may also use a weak notion of rationality, or at least a notion of rationality of human agents, with limited computational resources. The distinctions towards which Frege was striving are better understood nowadays from the point of view of the treatment of limited rationality, which imposes itself even in logical matters. (shrink)

Frege introduced the distinction between sense and reference to account for the information conveyed by identity statements. We can put the point like this: if the meaning of a term is exhausted by what it stands for, then how can 'a =a' and 'a =b' differ in meaning? Yet it seems they do, for someone who understands all the terms involved would not necessarily judge that a =b even though they judged that a =a. It seems that 'a =b' (...) just says something more than the trivial ’a = a' - it seems to contain more information, in some sense of 'information'. So either we have to add something to explain this extra information, or sever the very plausible links between meaning and understanding. This is what some writers have called 'Frege's Puzzle' It is undeniable that there is a phenomenon here to be explained, and it was Frege's insight to see the need for its explanation. But how should we explain it? Frege's idea was to add another semantic notion - Sinn, or Sense -— to account for the information conveyed. Sense is part of the meaning of an expression: it is the 'cognitive value' of the expression, or that ’wherein the mode of presentation is contained' (Frege 1957 p.57). Sense has a role to play in systematically determining the meanings of complex expressions, and ultimately in fixing the contents of judgements. It is the senses of whole sentences — Gedanken or Thoughts - which are candidates for truth and falsehood, and which are thus the objects of our propositional attitudes. Of course, introducing the notion of sense in this way does not, by itself, tell us what sense is. It only imposes a condition on a theory of meaning (and ultimately) belief: that it must account for distinctions in cognitive value or 'mode of presentation' (this is not a trivial thesis —- some philosophers today would deny that an explanation of Frege's Puzzle must occur within semantics or the theory of meaning: see Salmon 1985). In this paper I want to explore one way of meeting this condition for the theory of names in natural language, by examining Kripke's well-known 'Puzzle about Belief' (Kripke 1979).. (shrink)

On the traditional deontic framework, what is required (what morality demands) and what is optimal (what morality recommends) can't be distinguished and hence they can't both be represented. Although the morally optional can be represented, the supererogatory (exceeding morality's demands), one of its proper subclasses, cannot be. The morally indifferent, another proper subclass of the optional-one obviously disjoint from the supererogatory-is also not representable. Ditto for the permissibly suboptimal and the morally significant. Finally, the minimum that morality allows finds no (...) place in the traditional scheme. With a focus on the question, What would constitute a hospitable logical neighborhood for the concept of supererogation?, I present and motivate an enriched logical and semantic framework for representing all these concepts of common sense morality. (shrink)

Editorial NoteThis paper was read by Michael Dummett at Leiden University on September 26, 1992 at the invitation by Göran Sundholm to address the topic mentioned in the title. Dummett’s lecture was part of a workshop, Meaning Theory and Intuitionism, with 12 invited speakers over three days. After the workshop, Dummett gave a copy of the manuscript to Sundholm together with permission to publish it. At the time, nothing came of the publication plans, nor did Dummett publish it in any (...) other form. The text has remained virtually unknown, and apart from a lecture of Per Martin-Löf, also at Leiden, on the same topic, it has received no scholarly attention. We are indebted to Dummett’s literary executor, Professor Ian Rumfitt, of All Souls College, Oxford, who after nearly three decades confirmed the earlier permission to publish.Göran SundholmAnsten Klev. (shrink)

Editorial NoteThis lecture was given by Per Martin-Löf at Leiden University on August 25, 2001 at the invitation by Göran Sundholm to address the topic mentioned in the title and to reflect on Dummett’s earlier effort of almost a decade before. The lecture was part of a three-day conference on Gottlob Frege. Sundholm arranged for the lecture to be recorded and commissioned Bjørn Jespersen to make a transcript. The information in footnote 1, which Sundholm provided, has been independently confirmed by (...) Thomas Ricketts in an email to the author. The present version has been edited by Ansten Klev. Following the displayed text there is a lacuna in the original transcript corresponding to a pause in the recording when the tape was changed. The continuous text of the present version is the result of a few additions to the original transcript suggested by Klev and agreed to by the author. (shrink)

As part of his attack on Frege’s ‘myth’ that senses reside in the third realm, Dummett alleges that Frege’s view that all objects are selbständig is an underlying mistake, since some objects depend upon others. Whatever the merits of Dummett’s other arguments against Frege’s conception of sense, this objection fails. First, Frege’s view that senses are third-realm entities is not traceable to his view that all objects are selbständig. Second, while Frege recognizes that there are objects that are dependent (...) upon other objects, he does not take this to compromise the Selbständigkeit of any objects. Thus, Frege’s doctrine that objects are selbständig does not make the claim of absolute independence that Dummett appears to have taken it to make. Nevertheless, in order to make a good case against Frege based on the dependency of senses, Dummett need only establish his claim that senses depend upon expressions: appeal to an absolute conception of independence is unnece... (shrink)

This contribution investigates the idea that an act of signification can be understood in terms of the self-referentiality that is typical of the biological organization. The capacity of a living being to interpret and appreciate its own environment can be understood as being grounded in its ability to perform self-referential experiences. We may call this the living being’s capacity of sense. In any act that generates sense, it is possible to distinguish a process of signification from its outcome, (...) but such a distinction between logical levels inevitably demands an external observer’s point of view. Hence, the concept of ‘subjectivity’ can be defined in terms of an absence of such distinction between logical levels. This absence is considered pivotal both for the self-referential organization of the living and for the generation of sense. A case example from the field of psychotherapy is added to illustrate the distinction as well as the non-distinction between logical levels of description. (shrink)

The paper challenges a widely held interpretation of Frege's conception of logic on which the constituent clauses of basic law V have the same sense. I argue against this interpretation by first carefully looking at the development of Frege's thoughts in Grundlagen with respect to the status of abstraction principles. In doing so, I put forth a new interpretation of Grundlagen §64 and Frege's idea of ‘recarving of content’. I then argue that there is strong evidence in Grundgesetze (...) that Frege did not hold the relevant sense-identity claim regarding basic law V. (shrink)

It is argued that Russell before 1905 saw no value in Frege's sense/reference distinction. This is clearest in the Mont Blanc correspondence. It is argued that Russell and Frege failed to engage because Frege lacked a grasp on the internal/external relations distinction. For Russell sense is either an external relation, objectionably separating out thought and reference, or an internal relation, so what is thought is altered such that we do not know what we are talking about. The novelty (...) of the present paper lies in the arrangement of the parts and the claim that Russellian propositions are not made up of the things themselves but of transparent representatives thereof. (shrink)

Although the terms ‘poles’, ‘bipolar’, and ‘bipolarity’ do not appear in the Tractatus, it is widely held that Wittgenstein maintained his commitment to bipolarity in the Tractatus. As it is usually understood, the principle of bipolarity is that every proposition must be capable of being true and capable of being false, which rules out propositions that are necessarily true or necessarily false. Here I argue that Wittgenstein was committed to bipolarity in the Tractatus, but getting a clear view of this (...) commitment requires a different understanding of bipolarity. Properly understood, bipolarity is the view that every proposition represents two possible states of affairs, one positive and the other negative. Of course, in the case of elementary propositions, the sense of a proposition is only the positive state of affairs. There is thus an asymmetry between what a proposition represents, its true-false poles, and what it says, its sense. In this paper I show how Wittgenstein accounted for this asymmetry in Notes on Logic and I consider two ways he might have accounted for it in the Tractatus. (shrink)

This paper concerns the question of how to draw inferences common sensically from uncertain knowledge. Since the early work of Shore and Johnson (1980), Paris and Vencovská (1990), and Csiszár (1989), it has been known that the Maximum Entropy Inference Process is the only inference process which obeys certain common sense principles of uncertain reasoning. In this paper we consider the present status of this result and argue that within the rather narrow context in which we work this complete (...) and consistent mode of uncertain reasoning is actually characterised by the observance of just a single common sense principle (or slogan). (shrink)

In abductive planning, plans are constructed as reasons for an agent to act: plans are demonstrations in logical theory of action that a goal will result assuming that given actions occur successfully. This paper shows how to construct plans abductively for an agent that can sense the world to augment its partial information. We use a formalism that explicitly refers not only to time but also to the information on which the agent deliberates. Goals are reformulated to represent the (...) successive stages of deliberation and action the agent follows in carrying out a course of action, while constraints on assumed actions ensure that an agent at each step performs a specific action selected for its known effects. The result is a simple formalism that can directly inform extensions to implemented planners. (shrink)

In this paper I argue in favour of a moderate and selective version of scientific realism with respect to the existence of some physical theoretical objects and the truth of some statements about them. The analysis of common sense or ordinary experience reveals that existence and truth assertions concerning familiar objects are warranted if they satisfy what we call the criteria of presence and invariance. Ordinary objects exemplify a form or a structure determined by constant and changing features with (...) respect to the variation of the conditions of observation and a content given in sensory presence. It is claimed that some theoretical physical objects that possess a structure or a form determined by invariant and variable characteristics relatively to a specified group of transformations and a content provided by observations on which the measurement of those characteristics is grounded can also be justifiably asserted to exist. We further show that this defence of scientific realism in physics doesn't fall prey to the objections that have been raised against the usual vindication of scientific realism based on the no-miracle argument. Some standard objections to scientific realism, such as the underdetermination of theories by observations and the pessimistic meta-induction, are examined and shown to be unconvincing. (shrink)

In this paper, we discuss the weakness of current action languages for sensing actions with respect to modeling domains with multi-valued fluents. To address this problem, we propose a language with sensing actions and multi-valued fluents, called AMK, provide a transition function based semantics for the language, and demonstrate its use through several examples from the literature. We then define the entailment relationship between action theories and queries in AMK, denoted by ⊧AMK, and discuss some properties about AMK.