The paper emphasizes significant resemblances between the Informal Logic Initiative and the Lvov-Warsaw School – the Polish philosophical movement, the rise of which is associated with “the Golden Age of Science and Letters”. The correspondence between informal logic and the logical studies of the LWS will be explored by discussing their subject-matter, goals, and methods. The project focused on applying logical studies of the LWS in analyzing and assessing arguments will be proposed.

A commonplace of modern logic is that traditional logic, because it accepted the supposedly mistaken inference from general to particular propositions, perceived as valid a good number of invalid inference patterns. Yet many people find the allegedly invalid inference patterns intuitively valid. Four arguments that might be used to justify modern logic's judgment fail to provide good reason to provide modern logic pride of place. Of the three responses to failure of the arguments for preferring mode rn to traditional logic (...) considered, the most radical is recommended. (shrink)

The dissertation is an investigation into the structure of Aristotle's modal propositions through careful attention to the text of the Prior Analytics. I take account not only of recent attempts to formalize Aristotle's modal syllogistic but also of the discussion that Aristotle himself provides about modal statements. I provide evidence that his modal propositions are to be construed in a de re manner and then go on to investigate the problems raised by a de re analysis, particularly those problems concerned (...) with Aristotle's modal conversion principles. A large part of my project is to show that these can be given a valid de re analysis that sits well with the results Aristotle sketches. Terms in modal syllogistic premises are shown to be restricted in ways that reflect Aristotle's early metaphysics and notions of predication. (shrink)

This paper argues that Carol Gilligan’s Ethic of Care has strong affinities with the Buddhist concept of karuna (compassion) which, Jay Garfield has argued, is the necessary foundation of rights theory. Its central argument is that both moral compassion and thus rights theory are grounded in the natural compassionate care a mother exercises in order to promote the flourishing of her child without which children, and consequently adult society, would not survive in any form. Wittgenstein’s concept of language-games is brought (...) to bear on Buddhist philosophy to foreground the rootedness of human experience in connection and empathy. This further supports the naturalness of compassionate care, the Ethic of Care and karuna. Finally, mindfulness meditation is proposed as a practice appropriate for the educational context for the development of karuna as a moral resource for personal, civil and professional life. (shrink)

The thesis of the paper holds that some future developments of argumentation theory may be inspired by the rich logico-methodological legacy of the Lvov–Warsaw School (LWS), the Polish research movement that was most active from 1895 to 1939. As a selection of ideas of the LWS which exploit both formal and pragmatic aspects of the force of argument, we present: Ajdukiewicz’s account of reasoning and inference, Bocheński’s analyses of superstitions or dogmas, and Frydman’s constructive approach to legal interpretation. This paper (...) does not aim at exhaustive elaboration of any of these topics or their usefulness in current discussions within argumentation theory. Rather, we intend to indicate chosen directions of a potentially fruitful research program for the emerging Polish School of Argumentation which would consist in application of methods and conceptions elaborated by the LWS to selected open problems of contemporary research on argumentation. (shrink)

We construct an extension P of the standard language of classical propositional logic by adjoining to the alphabet of a new category of logical-pragmatic signs. The well formed formulas of are calledradical formulas (rfs) of P;rfs preceded by theassertion sign constituteelementary assertive formulas of P, which can be connected together by means of thepragmatic connectives N, K, A, C, E, so as to obtain the set of all theassertive formulas (afs). Everyrf of P is endowed with atruth value defined classically, (...) and everyaf is endowed with ajustification value, defined in terms of the intuitive notion of proof and depending on the truth values of its radical subformulas. In this framework, we define the notion ofpragmatic validity in P and yield a list of criteria of pragmatic validity which hold under the assumption that only classical metalinguistic procedures of proof be accepted. We translate the classical propositional calculus (CPC) and the intuitionistic propositional calculus (IPC) into the assertive part of P and show that this translation allows us to interpret Intuitionistic Logic as an axiomatic theory of the constructive proof concept rather than an alternative to Classical Logic. Finally, we show that our framework provides a suitable background for discussing classical problems in the philosophy of logic. (shrink)

The author tends to emphasize that there are at least three reasons to analyze Callimachus\' epigram about Diodorus : First of all, the date of this epigram shows us that it represents the earliest information about Diodorus doctrine. Second, another support of its authenticity could be found in fact that this epigram expressing part of the atmosphere following, and also remaining after, discussing the Diodorian topics. Third, its philosophical relevance, usually minimized in classical literature, could be found in those facts (...) that it could show the way out in many today dilemmas about his philosophical claims and support some of our contemporary assumptions about its logical conception, as well as that of space, time, and meaning of statements. The author defends a position that it is necessary to develop well-grounded and methodologically relevant base covering the historical reconstruction and the interpretation of ancient logical theories. (shrink)

I characterize the deductivist ideal of justification and, following to a great extent Toulmin’s work The Uses of Argument, I try to explain why this ideal is erroneous. Then I offer an alternative model of justification capable of making our claims to knowledge about substantial matters sound and reasonable. This model of justification will be based on a conception of justification as the result of good argumentation, and on a model of argumentation which is a pragmatic linguistic reconstruction of Toulmin’s (...) model of argument. (shrink)

The nominalist attitude in medieval logic supported a fully extensional conception of the sense of expressions. Many arguments against this approach were raised at that time. I would like to show in this article that there is a extensional conception of notions in current logic, namely in the interpretation of formal theories and the creation models of them and that, and how, traditional arguments against the extensional conception are relevant also for logic today.

Discrete supposition occurs whenever a discrete term, such as ‘Socrates‘, is the subject of a given proposition. I propose to examine this apparently simple notion. I shall draw attention to the incongruity, within a general theory of the semantic variation of terms in a propositional context, of the notion of discrete supposition, in which a term usually has a single semantic correlate. The incongruity comes to the fore in those treatises that attempt to describe discrete supposition as a sort of (...) personal supposition, although the same term cannot be in simple supposition in another propositional context, because it has no significate distinct from its suppositum. This shows a fundamental link between common signification, simple supposition and predicability, three notions that rely on the existence of a significate distinct and independent from the suppositum of the term. The connection is to be seen especially in William of Sherwood’s Introductiones, the only author of a terminist Summa who recognizes the existence of simple supposition for discrete terms. (shrink)

Some authors have talken about the problem of the future contingents Aristotle exposed in De Interpretatione IX. But most of them do not explain the role of that chapter in his own work. Last analysis always try to find a formal solution. And this is very significative because De Interpretatione is a treatise that belongs to the semantic of the Organon. In this article we show that: 1. The aim of the problem of future contigents is not only formal and (...) the frame of the Aristotle’s solution. 2. Its implication with others important concepts in his philosophy like “substance”, “truth” and “dialectics”. (shrink)

This paper presents the main aspects of the views of the Tibetan logician Phya pa Chos kyi seng ge (1109–1169) on argumentation “by consequence” (thal ʼgyur, Skt. prasaṅga) based on his exposition of the topic in the fifth chapter of his Tshad ma yid kyi mun sel and on a parallel excursus in his commentary on Dharmakīrti’s Pramānaviniścaya. It aims at circumscribing primarily the nature and function of consequences (thal ʼgyur/thal ba) for this author—in particular the distinction between “proving consequences” (...) and “refuting consequences”—and the form prescribed for their enunciation in the context of debate. In addition to pointing out differences with the systems adopted by his predecessors, contemporaries and successors, the paper also discusses some of the similarities and differences between Phya pa’s understanding of argumentation by consequence and the notion of reductio ad absurdum in Western logic. (shrink)

In this paper we discuss the difference between (...) proliferations of logic systems, the questions of relativity and universality of logic and the position and interaction of logic with regards to other sciences such as physics, biology, mathematics and computer science. (shrink)

We discuss external and internal graphical and linguistic representational systems. We argue that a cognitive theory of peoples' reasoning performance must account for (a) the logical equivalence of inferences expressed in graphical and linguistic form, and (b) the implementational differences that affect facility of inference. Our theory proposes that graphical representation limit abstraction and thereby aid “processibility”. We discuss the ideas of specificity and abstraction, and their cognitive relevance. Empirical support both comes from tasks which involve the manipulation of external (...) graphics and tasks that do not. For the former, we take Euler's (1772) circles, provide a novel computational reconstruction, show how it captures abstractions, and contrast it with earlier construals and with Johnson‐Laird's (1983) mental models representations. We demonstrate equivalence of the graphical Euler system, and the nongraphical mental models system. For tasks not involving manipulation of external graphics, we discuss text comprehension, and the mental performance of syllogisms. By positing an internal system with the same specificity as Euler's circles, we cover the mental models data, and generate new empirical predictions. Finally, we consider how the architecture of working memory explains why such specific representations are relatively easy to store. (shrink)

The concept of truth arises from puzzling over distinctions between the real and the apparent, while the origin of these distinctions lies in the neurobiology of mammalian cerebral lateralization, that is, in the evolution of brains that can address the world both indicatively and subjunctively; brains that represent the world both categorically and hypothetically. After some 2,500 years of thinking about it, the Western philosophical tradition has come up with three major theories of truth: correspondence, coherence, and pragmatist. Traditional philosophy (...) has nevertheless failed to arbitrate much among these views; certainly no clear winner has emerged. I argue, however, that contemporary neuroscience provides adequate theoretical grounds for a unified theory of truth. More specifically, I contend that the correspondence, the coherence, and the pragmatic utility of symbols are each biological features of our neurophysiological information processing systems—that is to say, our brains. On my view, the traditional trifurcation of philosophical accounts of the predicate, “is true”, stems from a trifurcation of focus on the information latent in sensory, motor, and somatosensory cortices of the human brain. (shrink)

I provide an interpretation of Wittgenstein's much criticized remarks on Gödel's First Incompleteness Theorem in the light of paraconsistent arithmetics: in taking Gödel's proof as a paradoxical derivation, Wittgenstein was right, given his deliberate rejection of the standard distinction between theory and metatheory. The reasoning behind the proof of the truth of the Gödel sentence is then performed within the formal system itself, which turns out to be inconsistent. I show that the models of paraconsistent arithmetics (obtained via the Meyer-Mortensen (...) collapsing filter on the standard model) match with many intuitions underlying Wittgensteins philosophy of mathematics, such as its strict finitism and the insistence on the decidability of any meaningful mathematical question. (shrink)

This essay discusses Peirce’s appeal to logical machines as an argument against psychologism. It also contends that some of Peirce’s anti-psychologistic remarks on logic contain interesting premonitions arising from his perception of the asymmetry of proof complexity in monadic and relational logical calculi that were only given full formulation and explication in the early twentieth century through Church’s Theorem and Hilbert’s broad-ranging Entscheidungsproblem.

We revisit a typological puzzle due to Horn (Doctoral Dissertation, UCLA, 1972) regarding the lexicalization of logical operators: in instantiations of the traditional square of opposition across categories and languages, the O corner, corresponding to ‘nand’ (= not and), ‘nevery’ (= not every), etc., is never lexicalized. We discuss Horn’s proposal, which involves the interaction of two economy conditions, one that relies on scalar implicatures and one that relies on markedness. We observe that in order to express markedness and to (...) account for a bigger typological puzzle, namely the absence of lexicalizations of ‘XOR’ (= exclusive or), ‘all-or-none’, and many other imaginable logical operators, one must restrict the basic lexicalizable elements to a small set of primitives. We suggest that an ordering based perspective, following Keenan and Faltz (Boolean semantics for natural language, 1985), makes the stipulated primitives that we arrive at more natural. We also propose a modification to Horn’s proposal, based on recent work on implicatures, in which only the implicature condition is operative and in which markedness is part of the definition of the alternatives for scalar implicatures rather than an independent condition. (shrink)

If the healthy and the pathological are not merely judgments qualifiers, but real phenomena, it must be possible to define both of them positively, which, in this context, means as factual contraries. On the other hand, only a privative definition, either of the pathological as 'non-healthy', or of the healthy as 'non-pathological', can rationally circumscribe all possible states of an organism. This fluctuation between two meanings of the 'healthy'-'pathological' opposition, factual vs. rational, characterizes the ordinary usage of these concepts and (...) puts all philosophical definitions in a hopeless situation. Although a scientific definition may conceal this equivocation by adequately setting out the terms of the problem of discriminating between the 'healthy' and the 'pathological', it could explain some of the difficulties met in determining 'gold standards', in the choice of separators, and in the assessment of the diagnostic qualities of tests. (shrink)

In his paraphasis of Aristotle’s Metaphysics, Avicenna seems to adopt a first principle distintc form the one adopted by the Greek philosopher for this science. In fact, some interpreters consider him as prefering the principle of third excluded instead of the principle of non contradiction. Since I desagree with this thesis, I propose to analyse here Avicenna’s formulation of the first principle. In order to do that, I propose, first, to clarify the meaning of the first principle by looking to (...) one of the most important modern critics: Jan Lukasiewicz. To put it briefly, the question I will try to answer is: how Avicenna and Aristotle justify the nature of the logical relations. The article finishes with make some general remarks on Avicenna’s defense of the first principle. (shrink)

It is widely known that Kasimir Twardowski was a student of Franz Brentano. In view of the fact that Brentano generally had great impact through his lectures, especially during his Vienna period (1874-1895), and consequently became one of the towering figures of Austrian philosophy, it is a matter of no small interest to determine how he influenced Twardowski. I’ll first consider presentations as they are described in Brentano’s psychology and then proceed to discuss Brentano’s account of the latter in his (...) logic. (shrink)

This paper surveys the common approach to quantification and generalised quantification in formal linguistics and philosophy of language. We point out how this general setting departs from empirical linguistic data, and give some hints for a different view based on proof theory, which on many aspects gets closer to the language itself. We stress the importance of Hilbert's oper- ator epsilon and tau for, respectively, existential and universal quantifications. Indeed, these operators help a lot to construct semantic representation close to (...) natural language, in particular with quantified noun phrases as individual terms. We also define guidelines for the design of the proof rules corresponding to generalised quantifiers. (shrink)

In this paper a dialogical account of begging the question is applied to various contexts which are not obviously dialogues: - reading prose, working through a deductive system, presenting a legal case, and thinking to oneself. The account is then compared with that in chapter eight of D. Walton'sBegging the Question (New York; Greenwood, 1991).

Woods' paper “Ideals of Rationality in Dialogue” raises six problems for dialogue theory. Woods is right about the seriousness of the problems, but one school of dialogue, that stemming from the work of Charles Hamblin, avoids each of Woods' problems by using commitment instead of belief and by using only immediate logical relations. This paper summarises the reasons Hamblin's school took this course, and explains how Woods' problems are thereby avoided.

In this paper a set of categorical sentences called an antilogistic tetrad is presented as a perspective on Aristotle's square of opposition. An antilogistic tetrad is formed by collecting the premises of a pair of valid syllogisms the conclusions of which are contradictory categorical sentences. A set of such premises serves to bring together Aristotle's concern with debate and the syllogism, and as such may be seen as a way of “completing” Aristotle's analysis of the square of opposition.The debate context (...) is characterized by opposing views for which arguments are offered. The square of opposition captures that contending of opposing views; and is also basic to the presentation of categorical sentences, a necessary condition for the syllogism. By using C. S. Peirce's notion of abductive argument to produce the middle term, and hence to construct deductive syllogistic arguments, antilogistic tetrads may be formed on any contended subject. For that reason, the process sketched above for forming antilogistic tetrads is called “completing the square of opposition.”. (shrink)

The aspects of Erhard Weigel's Analysis Aristotelica ex Euclide restituta that foreshadowed and helped form some characteristics of symbolic logic are highlighted: first, the idea of a pure form of a logical syllogism or of a mathematical proof and, second, a tentative arithmetisation of some aspects of logic. Also, Weigel's emphasis on the role of symbols and figures in the process of mathematical proof is discussed.

First I would like to thank Clarence Joldersma for his review of our Poststructuralism, Philosophy, Pedagogy. In particular, I would thank him for his opening sentence: “[t]his book is a response to a lack.” It is the notion of a lack, noted again later in his review, which I wish to take up mainly in this response. Rather than defending or elaborating our particular contributions to PPP—the latter would be a great indignity to my colleagues as I would not write (...) over them—I will take the opportunity to develop the theme of a lack, as I believe that Joldersma has raised a very important issue. But first I will respond briefly to some of Joldersma’s general and opening statements about the book, and my philosophical position in particular. (shrink)

Inference versus consequence , an invited lecture at the LOGICA 1997 conference at Castle Liblice, was part of a series of articles for which I did research during a Stockholm sabbatical in the autumn of 1995. The article seems to have been fairly effective in getting its point across and addresses a topic highly germane to the Uppsala workshop. Owing to its appearance in the LOGICA Yearbook 1997 , Filosofia Publishers, Prague, 1998, it has been rather inaccessible. Accordingly it is (...) republished here with only bibliographical changes and an afterword. (shrink)

Is it possible to distinguish communities of arguers by tracking the argumentation schemes they employ? There are many ways of relating schemes to communities, but not all are productive. Attention must be paid not only to the admissibility of schemes within a community of argumentational practice, but also to their comparative frequency. Two examples are discussed: informal mathematics, a convenient source of well-documented argumentational practice, and anthropological evidence of nonstandard reasoning.

History and Philosophy of Logic, Volume 32, Issue 2, Page 187-191, May 2011.

History and Philosophy of Logic, Volume 32, Issue 2, Page 191-193, May 2011.

A system of intermediate quantifiers (“Most S are P”, “m/n S are P”) is proposed for evaluating the rationality of human syllogistic reasoning. Some relations between intermediate quantifiers and probabilistic interpretations are discussed. The paper concludes by the generalization of the atmosphere, matching and conversion hypothesis to syllogisms with intermediate quantifiers. Since our experiments are currently still running, most of the paper is theoretical and intended to stimulate psychological studies.

The work of Hugh MacColl (1837–1909) suffered the same fate after his death as before it:despite being vaguely alluded to and in part even commended, on the whole it has remained an unknown quantity. Even worse, those of his ideas which have played a decisive role in the history of logic have been credited to his successors; this is especially the case with the definition of strict implication and the first formal development of formal modal logic. This paper takes an (...) initial step towards a rectification of this unfortunate misrepresentation, presenting a bibliography of MacColl’s most significant publications with particular regard to their reception. (shrink)

What all contemporary so-called aristotelian realists have in common has been identified by David Armstrong as the principle of instantiation. This principle has been put forward in different versions, but all of them have the following simple consequence in common: uninstantiated universals do not exist. Such entities are for the lotus-eating Platonist to countenance, but not for any sort of moderate realist. I shall argue that this principle, in any guise, is not the best way to differentiate aristotelianism from Platonism. (...) In its place, I shall suggest that the best way to differentiate the two versions of realism from each other is by means of a far more powerful idea: naturalism. And the surprising conclusion given this means of differentiation will be that contrary to the usual proclamations, Platonism will be the more naturalistic theory, whereas aristotelianism will come to be seen for what it really is, namely, non-naturalistic. (shrink)

I defend the compatibility of the classical theistic doctrine of divine providence, which includes infallible foreknowledge of all future events, with a libertarian understanding of creaturely free will. After setting out the argument for theological determinism, which purports to show the inconsistency of foreknowledge and freedom, I reject several responses as inadequate and then defend the ‚Ockhamist‛ response as successful. I further argue that the theory of middle knowledge or ‚Molinism‛ is crucial to the viability of the Ockhamist response, and (...) proceed to defend Molinism against the most pressing objections. Finally, I argue that a proper understanding of the Creator-creature relationship accounts for why no explanation can be given for how God’s middle knowledge comes about. (shrink)

Ever since ?ukasiewicz, it has been opinio communis that Aristotle's modal syllogistic is incomprehensible due to its many faults and inconsistencies, and that there is no hope of finding a single consistent formal model for it. The aim of this paper is to disprove these claims by giving such a model. My main points shall be, first, that Aristotle's syllogistic is a pure term logic that does not recognize an extra syntactic category of individual symbols besides syllogistic terms and, second, (...) that Aristotelian modalities are to be understood as certain relations between terms as described in the theory of the predicables developed in the Topics. Semantics for modal syllogistic is to be based on Aristotelian genus-species trees. The reason that attempts at consistently reconstructing modal syllogistic have failed up to now lies not in the modal syllogistic itself, but in the inappropriate application of modern modal logic and extensional set theory to the modal syllogistic. After formalizing the underlying predicable-based semantics (Section 1) and having defined the syllogistic propositions by means of its term logical relations (Section 2), this paper will set out to demonstrate in detail that this reconstruction yields all claims on validity, invalidity and inconclusiveness that Aristotle maintains in the modal syllogistic (Section 3 and 4). (shrink)

De Morgan's Formal Logic, which was published on virtually the same day in 1847 as Boole's The Mathematical Analysis of Logic, contains a logic of complex terms (LCT) which has been sadly neglected. It is surprising to find that LCT contains almost a full theory of Boolean algebra. This paper will: (1) provide some background to LCT; (2) outline its main features; (3) point out some gaps in it; (4) compare it with Boole's algebra; (5) show that it is a (...) lattice-theoretical formulation of Boolean algebra; (6) discuss some issues of historical priority; and (7) conclude with the puzzle of LCT's lack of influence. (shrink)

This paper considers the question of whether Mill's account of the nature and justificatory foundations of deductive logic is psychologistic. Logical psychologism asserts the dependency of logic on psychology. Frequently, this dependency arises as a result of a metaphysical thesis asserting the psychological nature of the subject matter of logic. A study of Mill's System of Logic and his Examination reveals that Mill held an equivocal view of the subject matter of logic, sometimes treating it as a set of psychological (...) processes and at other times as the objects of those processes. The consequences of each of these views upon the justificatory foundations of logic are explored. The paper concludes that, despite his providing logic with a prescriptive function, and despite his avoidance of conceptualism, Mill's theory fails to provide deductive logic with a justificatory foundation that is independent of psychology. (shrink)

This paper discusses George Boole’s two distinct approaches to the explanatory relationship between logical and psychological theory. It is argued that, whereas in his first book he attributes a substantive role to psychology in the foundation of logical theory, in his second work he abandons that position in favour of a linguistically conceived foundation. The early Boole espoused a type of psychologism and later came to adopt a type of anti-psychologism. To appreciate this invites a far-reaching reassessment of his philosophy (...) of logic. (shrink)

In this essay, I discuss some observations by Peirce which suggest he had some idea of the substantive metalogical differences between logics which permit both quantifiers and relations, and those which do not. Peirce thus seems to have had arguments?which even De Morgan and Frege lacked?that show the superior expressiveness of relational logics.

Charles L. Dodgson's reputation as a significant figure in nineteenth-century logic was firmly established when the philosopher and historian of philosophy William Warren Bartley, III published Dodgson's ?lost? book of logic, Part II of Symbolic Logic, in 1977. Bartley's commentary and annotations confirm that Dodgson was a superb technical innovator. In this paper, I closely examine Dodgson's methods and their evolution in the two parts of Symbolic Logic to clarify and justify Bartley's claims. Then, using more recent publications and unpublished (...) letters, I argue that Dodgson approached the elimination problem in class logic differently than his contemporaries, and in doing so, anticipated several important concepts and techniques in automated deductive reasoning. These materials also provide additional insight into his reasons for writing this book. (shrink)

For Ivor Grattan-Guinness on the occasion of his retirement. The work of Augustus De Morgan on symbolic logic in the mid-nineteenth century is familiar to historians of logic and mathematics alike. What is less well known is his work on probability and, more specifically, the use of probabilistic ideas and methods in his logic. The majority of De Morgan's work on probability was undertaken around 1837???1838, with his earliest publications on logic appearing from 1839, a period which culminated with the (...) publication of his Formal Logic in 1847. This article examines the overlap between his work on probability theory and logic during the earliest period of his interest in both. (shrink)

One way to determine the quality and pace of change in a science as it undergoes a major transition is to follow some feature of it which remains relatively stable throughout the process. Following the chosen item as it goes through reinterpretation permits conclusions to be drawn about the nature and scope of the broader change in question. In what follows, this device is applied to the change which took place in logic in the mid-nineteenth century. The feature chosen as (...) the focal point is the categorical syllogism. (shrink)