In a recent paper Johan van Benthem reviews earlier work done by himself and colleagues on ‘natural logic’. His paper makes a number of challenging comments on the relationships between traditional logic, modern logic and natural logic. I respond to his challenge, by drawing what I think are the most significant lines dividing traditional logic from modern. The leading difference is in the way logic is expected to be used for checking arguments. For traditionals the checking is local, (...) i.e. separately for each inference step. Between inference steps, several kinds of paraphrasing are allowed. Today we formalise globally: we choose a symbolisation that works for the entire argument, and thus we eliminate intuitive steps and changes of viewpoint during the argument. Frege and Peano recast the logical rules so as to make this possible. I comment also on the traditional assumption that logical processing takes place at the top syntactic level, and I question Johan’s view that natural logic is ‘natural’. (shrink)

Since the time of Aristotle's students, interpreters have considered Prior Analytics to be a treatise about deductive reasoning, more generally, about methods of determining the validity and invalidity of premise-conclusion arguments. People studied Prior Analytics in order to learn more about deductive reasoning and to improve their own reasoning skills. These interpreters understood Aristotle to be focusing on two epistemic processes: first, the process of establishing knowledge that a conclusion follows necessarily from a set of premises (that is, on the (...) epistemic process of extracting information implicit in explicitly given information) and, second, the process of establishing knowledge that a conclusion does not follow. Despite the overwhelming tendency to interpret the syllogistic as formal epistemology, it was not until the early 1970s that it occurred to anyone to think that Aristotle may have developed a theory of deductive reasoning with a well worked-out system of deductions comparable in rigor and precision with systems such as propositional logic or equational logic familiar from mathematical logic. When modern logicians in the 1920s and 1930s first turned their attention to the problem of understanding Aristotle's contribution to logic in modern terms, they were guided both by the Frege-Russell conception of logic as formal ontology and at the same time by a desire to protect Aristotle from possible charges of psychologism. They thought they saw Aristotle applying the informal axiomatic method to formal ontology, not as making the first steps into formal epistemology. They did not notice Aristotle's description of deductive reasoning. Ironically, the formal axiomatic method (in which one explicitly presents not merely the substantive axioms but also the deductive processes used to derive theorems from the axioms) is incipient in Aristotle's presentation. Partly in opposition to the axiomatic, ontically-oriented approach to Aristotle's logic and partly as a result of attempting to increase the degree of fit between interpretation and text, logicians in the 1970s working independently came to remarkably similar conclusions to the effect that Aristotle indeed had produced the first system of formal deductions. They concluded that Aristotle had analyzed the process of deduction and that his achievement included a semantically complete system of natural deductions including both direct and indirect deductions. Where the interpretations of the 1920s and 1930s attribute to Aristotle a system of propositions organized deductively, the interpretations of the 1970s attribute to Aristotle a system of deductions, or extended deductive discourses, organized epistemically. The logicians of the 1920s and 1930s take Aristotle to be deducing laws of logic from axiomatic origins; the logicians of the 1970s take Aristotle to be describing the process of deduction and in particular to be describing deductions themselves, both those deductions that are proofs based on axiomatic premises and those deductions that, though deductively cogent, do not establish the truth of the conclusion but only that the conclusion is implied by the premise-set. Thus, two very different and opposed interpretations had emerged, interestingly both products of modern logicians equipped with the theoretical apparatus of mathematical logic. The issue at stake between these two interpretations is the historical question of Aristotle's place in the history of logic and of his orientation in philosophy of logic. This paper affirms Aristotle's place as the founder of logic taken as formal epistemology, including the study of deductive reasoning. A by-product of this study of Aristotle's accomplishments in logic is a clarification of a distinction implicit in discourses among logicians--that between logic as formal ontology and logic as formal epistemology. (shrink)

Filling the need for an accessible, carefully structured introductory text in symbolic logic, Modern Logic has many features designed to improve students' comprehension of the subject, including a proof system that is the same as the award-winning computer program MacLogic, and a special appendix that shows how to use MacLogic as a teaching aid. There are graded exercises at the end of each chapter--more than 900 in all--with selected answers at the end of the book. Unlike competing texts, (...) class='Hi'>Modern Logic gives equal weight to semantics and proof theory and explains their relationship, and develops in detail techniques for symbolizing natural language in first-order logic. After a general introduction featuring the notion of logical form, the book offers sections on classical sentential logic, monadic predicate logic, and full first-order logic with identity. A concluding section deals with extensions of and alternatives to classical logic, including modal logic, intuitionistic logic, and fuzzy logic. For students of philosophy, mathematics, computer science, or linguistics, Modern Logic provides a thorough understanding of basic concepts and a sound basis for more advanced work. (shrink)

In face of persistent and notable efforts taking place in many parts of the world today to make modern logic a tool of legal thought, lawyers are inclined to ask: "What is the real significance of modern logic for us?" A sum mary answer to this question is: "Modern logic provides up-to-date principles and methods for tracing and display ing self-consistent thought, which is indispensable for ef ficient and proper performance of legal tasks." This answer may not (...) satisfy the questioner's curiosity about modern logic in the service of law. If he wants to know more, he is invited to join in an investigation of the various ways in which modern logic can prove useful in legal thought. The present book proposes to engage in such an investi gation, and in doing so it also endeavors to meet various challenges to legal logic. If the value of this logic is totally denied, a reaction to this denial is to ask what its reasonable alternative could possibly be. So far there appears to be no sensible reply to this question. The merit of many specific criticisms of legal logic is indisputable. (shrink)

An awareness of the wide scope of medieval logic and the role it played in university education at all levels, together with the way it was used in writings on both science and theology, is crucial for the historian of medieval thought. The growth of this awareness since the mid-twentieth century is shown by the ongoing expansion of editorial work, together with the discussion of the logic actually found in such prominent authors as Aquinas and Scotus. It has gone hand (...) in hand with the use of developments in modern logic. First came the realization that medieval logic extended beyond basic Aristotelian syllogistic, and could be related to modern developments in propositional and quantificational logic in... (shrink)

While for a long time the study of medieval logic focused on editorial projects and reconstructions of central medieval doctrines such as the theories of signification, supposition, consequences, and obligations, nowadays the spectrum of analysis has broadened and is increasingly informed by modern logical research, whose perspective is then applied to medieval logic. Promoting this tendency, logicians and researchers concerned with semantics in the Gesellschaft für Philosophie des Mittelalters und der Renaissance (GPMR) founded a working group bringing together medieval (...) logic and modern applied logic. The present volume is a seminal document of these interests and activities. It analyzes theories in medieval logic which are useful for solving questions of recent logic and explains crucial parts of medieval logic, philosophy, and theology by applying techniques of present-day logic. (shrink)

This paper deals with Ágnes Heller’s suggestion, in A Theory of Modernity (1999), to ascribe to science a central role in the ongoing development of modernity. As we shall argue, this is not merely a historical issue but, rather, a historical-philosophical one that entails the problem of defining modernity, science and technology and their mutual interconnections. As for modernity, according to Heller, it is a free developmental project without any foundations other than freedom itself. In particular, the evolution of science (...) and technology is one of its main developmental tendencies. Science, she argues, has become the dominant world explanation while technological thought is the corresponding dominant (but not unique) imaginary institution. Her attempt to isolate the essential cultural features of science-technology owes much to Habermas’s analyses of the 1960s on the technocratic developments of contemporary societies legitimized through an ideological employment of science. Like Habermas, Heller embraces an instrumental and problem-solving conception of technology and ‘normal’ science which appears questionable, however, in the light of conclusions on the intrinsic creativity of the science-technology interface deriving from historical epistemology and an externalist history of science. Considerations and examples derived from the recent agenda of historical epistemology could integrate Heller’s philosophical and cultural analysis of the role of science in modernity while challenging some of her assumptions. (shrink)

Chapter One: Constructions. Entities, constructions, and functions When one travels from Los Angeles to New York, going, say, by way of St. Louis, Chicago, ...

Logical reflection in early modern philosophy (EMP) is marked by the instability of the period, although it is more lasting (the Port-Royal Logic was nevertheless used as a handbook in philosophy courses until the end of the nineteenth century). It started in the sixteenth century and ended in the nineteenth century, a period of 300 years during which there were deep transformations in the conceptions of authority and scientific method. For the history of twentieth-century philosophy, it was the period (...) of “classical logic,” which lasted from the Renaissance to the linguistic turn conducted by Gottlob Frege. The period was used to be thought of as centuries of little or no original contribution to logic, in which conceptions of logic were tainted by rhetoric, epistemology, and psychologism in the worst sense (Kneale and Kneale 1962; Michael 1997). From the last decades of the twentieth century, however, scholars began to regard this period more accurately with respect to reflection and changes in logic and semantics. It has recently become a promising field for historical and conceptual research; today we can say that the legacy of early modern logical reformism has a philosophical, logical, and semantic value in itself. (shrink)

Offers an extremely bold, far-reaching, and unsuspected thesis in the history of philosophy: Aristotelianism was a dominant movement of the British philosophical landscape, especially in the field of logic, and it had a long survival. British Aristotelian doctrines were strongly empiricist in nature, both in the theory of knowledge and in scientific method; this character marked and influenced further developments in British philosophy at the end of the century, and eventually gave rise to what we now call British empiricism, which (...) is represented by philosophers such as John Locke, George Berkeley and David Hume. Beyond the apparent and explicit criticism of the old Scholastic and Aristotelian philosophy, which has been very well recognized by the scholarship in the twentieth century and which has contributed to the false notion that early modern philosophy emerged as a reaction to Aristotelianism, the present research examines the continuity, the original developments and the impact of Aristotelian doctrines and terminology in logic and epistemology as the background for the rise of empiricism.Without the Aristotelian tradition, without its doctrines, and without its conceptual elaborations, British empiricism would never have been born. The book emphasizes that philosophy is not defined only by the ‘great names’, but also by minor authors, who determine the intellectual milieu from which the canonical names emerge. It considers every single published work of logic between the middle of the sixteenth and the end of the seventeenth century, being acquainted with a number of surviving manuscripts and being well-informed about the best existing scholarship in the field. ​. (shrink)

This book treats ancient logic: the logic that originated in Greece by Aristotle and the Stoics, mainly in the hundred year period beginning about 350 BCE. Ancient logic was never completely ignored by modern logic from its Boolean origin in the middle 1800s: it was prominent in Boole’s writings and it was mentioned by Frege and by Hilbert. Nevertheless, the first century of mathematical logic did not take it seriously enough to study the ancient logic texts. A renaissance in (...) ancient logic studies occurred in the early 1950s with the publication of the landmark Aristotle’s Syllogistic by Jan Łukasiewicz, Oxford UP 1951, 2nd ed. 1957. Despite its title, it treats the logic of the Stoics as well as that of Aristotle. Łukasiewicz was a distinguished mathematical logician. He had created many-valued logic and the parenthesis-free prefix notation known as Polish notation. He co-authored with Alfred Tarski’s an important paper on metatheory of propositional logic and he was one of Tarski’s the three main teachers at the University of Warsaw. Łukasiewicz’s stature was just short of that of the giants: Aristotle, Boole, Frege, Tarski and Gödel. No mathematical logician of his caliber had ever before quoted the actual teachings of ancient logicians. -/- Not only did Łukasiewicz inject fresh hypotheses, new concepts, and imaginative modern perspectives into the field, his enormous prestige and that of the Warsaw School of Logic reflected on the whole field of ancient logic studies. Suddenly, this previously somewhat dormant and obscure field became active and gained in respectability and importance in the eyes of logicians, mathematicians, linguists, analytic philosophers, and historians. Next to Aristotle himself and perhaps the Stoic logician Chrysippus, Łukasiewicz is the most prominent figure in ancient logic studies. A huge literature traces its origins to Łukasiewicz. -/- This Ancient Logic and Its Modern Interpretations, is based on the 1973 Buffalo Symposium on Modernist Interpretations of Ancient Logic, the first conference devoted entirely to critical assessment of the state of ancient logic studies. (shrink)

The final work of the esteemed philosopher William Demopoulos supplants logical empiricism's accounts of physical theories, which fail to satisfactorily engage modern physics. Arguing for a new appreciation of the tightly woven character of theory and evidence, Demopoulos offers novel insights into the distinctive nature of quantum reality.

In selecting the papers for this volume I have excluded all physics papers proper. I have further omitted all book rev.iews. Instead, I have included two papers not published previously; they are marked by an asterisk (*) in the table of contents. Since many of the papers were occasioned by Symposia or similar gatherings their chronological order is rather accidental. Hence I have tried to group the papers thematically into four parts. Within each part the order of sequence is from (...) the more general to the more special, or from a more popular to a more technical treatment. The same principle has been applied to the sequential order of the parts. The foundational papers on quantum mechanics have been arranged in a somewhat dif ferent manner. Chapters XVI-XIX are concerned with the logic of complementarity while in Chapters XX-XXII a more radical recon ceptualization is carried out. Two of the older papers (Chapters VI and VIII) have been revised to bring them more into line with present terminology. Other papers have been corrected by additions and omissions. Additions are marked by square brackets [ ], while double square brackets [[ II signify omis sions or parts to be omitted. Hence [[A]] [B] means that 'A' should be replaced by 'B'. The heading of one paper (Chapter XX) has been changed to make it more descriptive. (shrink)

Hermann Grassmann's Ausdehnungslehre of 1844 and his Lehrbuch der Arithmetik of 1861 are landmark works in mathematics; the former not only developed new mathematical fields but also both contributed to the setting of modern standards of rigor. Their very modernity, however, may obscure features of Grassmann's view of the foundations of mathematics that were not adopted since. Grassmann gave a key role to the learning of mathematics that affected his method of presentation, including his emphasis on making initial assumptions (...) explicit. In order to better understand this less well-known aspect of his work it will help to examine why some commentators have overlooked his theme of unifying logic, pedagogy and foundations, while others have recognised it. (shrink)

The word "modem" in the title of this book refers primarily to post-medieval discussions, but it also hints at those medieval mo dal theories which were considered modem in contradistinction to ancient conceptions and which in different ways influenced philosophical discussions during the early modem period. The me dieval developments are investigated in the opening paper, 'The Foundations of Modality and Conceivability in Descartes and His Predecessors', by Lilli Alanen and Simo Knuuttila. Boethius's works from the early sixth century belonged (...) to the sources from which early medieval thinkers obtained their knowledge of ancient thought. They offered extensive discus sions of traditional modal conceptions the basic forms of which were: (1) the paradigm of possibility as a potency striving to realize itself; (2) the "statistical" interpretation of modal no tions where necessity means actuality in all relevant cases or omnitemporal actuality, possibility means actuality in some rel evant cases or sometimes, and impossibility means omnitemporal non-actuality; and (3) the "logical" definition of possibility as something which, being assumed, results in nothing contradic tory. Boethius accepted the Aristotelian view according to which total possibilities in the first sense must prove their met tle through actualization and possibilities in the third sense are assumed to be realized in our actual history. On these presump tions, all of the above-mentioned ancient paradigms imply the Principle of Plenitude according to which no genuine possibility remains unrealized. (shrink)

In this volume, Bimal K. Matilal blends knowledge contained in original Sanskrit texts and modern philosophical terminology in interpreting and reconstructing early philosophical theories, highlighting the critical and analytical nature of the Indian philosophical tradition.

This paper determines the state of mind, logic and language in medieval philosophy. It also exhibits the journey from medieval to early modern philosophy. In medieval philosophy, concept of mind was intimately connected soul or spirit with its harmony with religious tradition. Logic and language as well were corresponding with religion and faith. However in early modern philosophy the schema of mind, logic and language were different. These concepts were bailed from the clutches of religious dogmatism and faith (...) towards the mechanical correspondence. Mind was treated as non-modular. Logical truth which includes mostly inductive and deductive in medieval and modern period has been explained clearly. This paper shows the evolution of these concepts in the tradition of Rationalists, Empiricists and Critical Philosophers. In this paper I would as well show the interrelation between mind along with language and logic. This write up further shows the development of language in medieval period to early modern philosophy. it also demonstrates the footprints for the analytical study and international study in contemporary philosophy. (shrink)

Being mainly concerned with the origins and development of formal logic, current “histories of logic” often devote scarce, if any, space to logic in the early modern period. In standard narratives, emphasis is put, on one side, on Aristotle’s Organon and on the Stoics’ logic of propositions, and on the other side, on the development of mathematical logic from Boole and Frege on. The picture often emerging from such reconstructions represents early modern philosophers—net of their criticisms of Aristotelian (...) syllogism— as largely estranged from the discipline. It is true that, the medieval period’s concern with semantic and inference issues has been accounted... (shrink)

_Sweet Reason: A Field Guide to Modern Logic, 2nd Edition_ offers an innovative, friendly, and effective introduction to logic. It integrates formal first order, modal, and non-classical logic with natural language reasoning, analytical writing, critical thinking, set theory, and the philosophy of logic and mathematics. An innovative introduction to the field of logic designed to entertain as it informs Integrates formal first order, modal, and non-classical logic with natural language reasoning, analytical writing, critical thinking, set theory, and the philosophy (...) of logic and mathematics Addresses contemporary applications of logic in fields such as computer science and linguistics A web-site linked to the text features numerous supplemental exercises and examples, enlightening puzzles and cartoons, and insightful essays. (shrink)

This book is written for those who wish to learn some basic principles of formal logic but more importantly learn some easy methods to unpick arguments and assess their value for truth and validity. -/- The first section explains the ideas behind traditional logic which was formed well over two thousand years ago by the ancient Greeks. Terms such as ‘categorical syllogism’, ‘premise’, ‘deduction’ and ‘validity’ may appear at first sight to be inscrutable but will easily be understood with examples (...) bringing the subjects to life. Traditionally, Venn diagrams have been employed to test arguments. These are very useful but their application is limited and they are not open to quantification. The mid-section of this book introduces a methodology that makes the analysis of arguments accessible with the use of a new form of diagram, modified from those of the mathematician Leonhard Euler. These new diagrammatic methods will be employed to demonstrate an addition to the basic form of syllogism. This includes a refined definition of the terms ‘most’ and ‘some’ within propositions. This may seem a little obscure at the moment but one will readily apprehend these new methods and principles of a more modern logic. (shrink)

THE notion of quantity is basic and it is no surprise that Aristotle refers to it in many places. There are two main discussions, that in the Categories—a part of the Organon which is of great interest to modern logicians and that spread over the physical treatises. Naturally the two treatments overlap, but modern logic is at a far remove from classical cosmology and it is fairly easy to separate them at their sources. This I have attempted to (...) do by considering quantity as an attribute and as divisible. There follows a brief consideration of the notions arrived at for their relevance to modern mathematics with particular reference to the real number system and the notion of infinity. (shrink)

In the paper, a detailed analysis of some new logical aspects of Cantor’s diagonal proof of the uncountability of continuum is presented. For the first time, strict formal, axiomatic, and algorithmic definitions of the notions of potential and actual infinities are presented. It is shown that the actualization of infinite sets and sequences used in Cantor’s proof is a necessary, but hidden, condition of the proof. The explication of the necessary condition and its factual usage within the framework of Cantor’s (...) proof makes, Cantor’s proof invalid. It’s shown that traditional Cantor’s proof has a second necessary, but hidden as well, condition which is teleological by its nature, i.e., is not mathematical. The explication of the second necessary condition makes Cantor’s statement on the uncountability of continuum unprovable from the point of view of classical logic.One of the most dramatic facts in history of science is connected just with the notion of actual infinity and consists in the following. On the one hand, Aristotle, Berkeley, Locke, Descartes, Spinoza, Gauss, Kant, Cauchy, Kronecker, Hermite, Poincaré, Bair, Borel, Brouwer, Quine, Wittgenstein, Weyl, Luzin, and a lot of other outstanding creators of classical logic and classical mathematics, during millenniums, stated categorically and insistently warned about that the actual infinity is a self-contradictory notion and its usage in mathematics is inadmissible (e.g., according to Poincare, “There is no actual infinity. - Cantorians forgot that and fell into contradictions. Later generations will regard Mengenlehre (set theory) as a disease from which one has recovered”). On the other hand, a lot of outstanding scientists of the XX c.c., such as Hilbert, Church, Turing, Gödel, etc., and modern axiomatic set theory as a whole ignored this (intuitive though) opinion of genii and accepted Cantor’s “transfinite paradise”, based on the actual infinity. In the paper some logical, philosophical, and psychological aspects of this historical “favorable opposition” are analyzed, and the fact that the scientific intuition of genii has won the historical battle against the mytho-’logic’ of Cantor’s transfinite ‘paradise’ is explained and logically justified. (shrink)

Review of Karel Lambert, Meinong and the Principle of Independence: Its Place in Meinong's Theory of Objects and Its Significance in Contemporary Philosophical Logic.

While there are good reasons to think that Hegel would not engage with modern scepticism in the Science of Logic, this article argues that he nevertheless does so in a way that informs the text's conception of logic as the latter pertains to metaphysics. Hegel engages with modern scepticism's general concerns that philosophy should begin without unexamined presuppositions and should come to attain not only knowledge of truth, but corresponding second-order knowledge: knowledge of knowing truth. These concerns inform (...) two needs that Hegel formulates for first philosophy, which logic—by unifying with metaphysics, which is traditionally synonymous with first philosophy—is to satisfy. However, logic, for the Logic, is unified with metaphysics as a science of absolute knowing, the form of thinking involved in traditional metaphysics. As such, logic, for the Logic, is neither anti-metaphysical nor reducible to metaphysics, but is rather a science of metaphysical thinking, which, for Hegel, includes metaphysics. The article emphasizes how Hegel's construal of logic as a science of absolute knowing avoids running into the ‘swimming problem’ that Hegel raises against, broadly, epistemological forms of first philosophy. (shrink)

Hegel frequently claimed that the heart of his entire system was a book widely regarded as among the most difficult in the history of philosophy, The Science of Logic. This is the book that presents his metaphysics, an enterprise that he insists can only be properly understood as a “logic,” or a “science of pure thinking.” Since he also wrote that the proper object of any such logic is pure thinking itself, it has always been unclear in just what sense (...) such a science could be a “metaphysics.” -/- Robert B. Pippin offers here a bold, original interpretation of Hegel’s claim that only now, after Kant’s critical breakthrough in philosophy, can we understand how logic can be a metaphysics. Pippin addresses Hegel’s deep, constant reliance on Aristotle’s conception of metaphysics, the difference between Hegel’s project and modern rationalist metaphysics, and the links between the “logic as metaphysics” claim and modern developments in the philosophy of logic. Pippin goes on to explore many other facets of Hegel’s thought, including the significance for a philosophical logic of the self-conscious character of thought, the dynamism of reason in Kant and Hegel, life as a logical category, and what Hegel might mean by the unity of the idea of the true and the idea of the good in the “Absolute Idea.” The culmination of Pippin’s work on Hegel and German idealism, no Hegel scholar or historian of philosophy will want to miss this book. (shrink)

This study concentrates on exploring the ‘logic’ of modern universities in China-a working concept that promotes a more in-depth discourse on the implicit illustrations of the ‘logic’ of universiti...