In the discussion at hand I have attempted to pave the way for such a treatment of the principle of contradiction. In a number of respects it seems to me worthwhile to relate my critical exposition to Aristotle's train of thought. Indeed, every critique must be raised against something substantial, otherwise it generally becomes the critic's leisurely game with his own cerebral phantasies. Now Aristotle's intuitions regarding the principle of contradiction are, for the most part and clear down to the (...) present day, the usual and traditional ones; and arguments for and against the principle can be found together in the Stagirite in greater completeness than in any one modern textbook of logic. My investigation will proceed with the Aristotelian text at hand and with regard to the results of symbolic logic. The most important results shall be sketched very briefly in the following. (shrink)

La logique des stoïciens a été déjà étudiée par Prantl, Zeller et Brochard. Aucun d’entre eux ne l’a comprise, car aucun n’avait de formation suffisante en logique. Il est vrai que cela ne peut même pas leur être reproché, car, après tout, où pouvaient-ils l’apprendre? Leurs jugements sur la logique stoïcienne n’ont aucune valeur. Ce n’est qu’aujourd’hui que nous savons, grâce à la logique mathématique, que la logique des stoïciens est un système entièrement différent de la syllogistique d’A...

THE great Polish logician Jan Lukasiewicz died on February 13, 1956 in Dublin, where, thanks to the hospitality of the Irish Government and the Royal Irish Academy, he had spent the last ten years of his life as a distinguished professor of the Academy. Thanks to the help he received in Dublin, he was able not only to reconstruct and prepare his papers for publication, but was also able to carry on new research in the field of symbolic logic, (...) obtaining several new and important results. Thus, due to the odd and dreadful historical circumstances of our times, the name of this Polish scientist is connected not only with his native country, but also with Ireland. (shrink)

This volume offers to the English-speaking world a collection of important works by the eminent twentieth century logician, Jan Lukasiewicz, many of which are here translated into English for the first time. This edition differs significantly from the Polish edition which appeared in 1961—containing ten logic papers not appearing there and omitting articles primarily of interest to the Polish reader. In addition to writing in Polish, Lukasiewicz also published works in French, English, and notably in German, and sometimes (...) translated his own works from one language to another. One of the most valuable works on the history of logic is Lukasiewicz’ paper, "On the History of the Logic of Propositions". Lukasiewicz points out the difference between the two basic areas of formal logic, the logic of propositions and the logic of terms, undifferentiated before the development of modern mathematical logic. The understanding of this distinction leads Lukasiewicz to trace the history of propositional logic back to its original development by the Stoics, its further development by the medieval Scholastics, and its axiomatization by Gottlob Frege. The status of mathematical logic is discussed in various works. The most basic system is propositional logic, upon which depend the other logical disciplines and also mathematics. Mathematical logic, also called logistic, is independent of philosophy and espouses no philosophical viewpoint. Early in his career, Lukasiewicz refers to mathematical logic as the logic of algebra and uses mathematical symbolism to represent logical propositions. Later he introduces what we now call "Polish notation," in particular, "Cpq" for "if p, then q" and "Np" for "it is not the case that p" for the primitive functions, eliminating the need for punctuation. He adopts the symbols Π and Σ for quantification from Charles S. Peirce, and also brings to light the almost unknown fact that it was Peirce who invented the matrix method in 1885. The paper, "Investigations into the Sentential Calculus", written by Lukasiewicz and Tarski embodies the results of a decade of research on the sentential calculus initiated by Lukasiewicz at the University of Warsaw systematically compiling the contributions of five logicians: Lindenbaum, Sobocinski, Wajsberg, Tarski, and Lukasiewicz. The approach is metalogical and depends heavily upon set theoretic concepts; it covers both the matrix and axiomatic methods. One of the problems that preoccupied Lukasiewicz was that of determinism, which led to his development of three-valued logic. A proposition such as "I shall be in Warsaw at noon on 21 December of next year" is neither true nor false; a third truth value is needed, one which Lukasiewicz calls "the possible." Another area to which Lukasiewicz contributed is modal logic, proving that modal logic cannot be two-valued. Lukasiewicz’ analysis and axiomatization of Aristotle’s syllogistic is not included in the present volume since an English edition by Lukasiewicz on this topic is available. We have here briefly touched upon a few of Lukasiewicz’ numerous achievements in logic; the best means of appreciating them is to read his works.—T. G. N. (shrink)

Jan Salamucha was born on the 10th of June 1903 in Warsaw and murdered on the 11th of August 1944 in Warsaw during the Warsaw Uprising very early on in his scholarly career. He is the most original representative of the branch of the Lvov-Warsaw School known as the Cracow Circle. The Circle was a grouping of scholars who were interested in reconstructing scholasticism and Christian philosophy in general by means of mathematical logic. As Jan Lukasiewicz’s successor in the (...) area of logic and Konstanty Michalski’s student in the area of the history of medieval thought, Salamucha had an excellent preparation for this task. His main achievements include a masterful logical analysis of the proof _ex motu _for the existence of God, a modern interpretation of analogical notions and a comprehensive approach to the problem of essence. He also contributed several historical studies: he examined Aristotle’s theory of deduction, he reconstructed William Ockham’s propositional logic and established the authenticity of his treatise on _insolubilia,_ and he identified the historical sources of the antinomies in Antiquity and the Middle Ages. He did not shy away from popularizing philosophy, and in that work he was able to elucidate rather than oversimplify the complexities of philosophy. (shrink)

In this note, we show that the first-order logic IKω is sound with regard to the models obtained from continuum-valued Łukasiewicz-models for first-order languages by treating the quantifiers as infinitary strong disjunction/conjunction rather than infinitary weak disjunction/conjunction. Moreover, we show that these models cannot be used to provide a new consistency proof for the theory of truth IKTω obtained by expanding IKω with transparent truth, because the models are inconsistent with transparent truth. Finally, we show that whether or not this (...) inconsistency can be reproduced in the sequent calculus for IKTω depends on how vacuous quantification is treated. (shrink)

Ancien etudiant de Brentano et de Zimmerman, Kazimierz Twardowski, apres son election a la chaire de philosophie a Lvov en 1895, crea autour de lui un cercle d'etudiants et de collaborateurs exceptionnel, connu aujourd'hui sous le nom d'Ecole de Lvov-Varsovie. A mi-chemin entre Vienne et Cambridge, c'est a Lvov, et puis partiellement a Varsovie, que Jan Lukasiewicz, Stanislaw Lesniewski, Alfred Tarski, Kazimierz Ajdukiewicz, Tadeusz Kotarbinski et bien d'autres encore, repenserent dans un esprit d'analyse les questions fondamentales de la philosophie (...) du langage, de la logique, de la philosophie des sciences et des mathematiques. Plus qu'une simple traduction, ce livre est une version revisee de la monographie desormais classique que Jan Wolenski, connu pour ses travaux non seulement en histoire de la philosophie analytique, mais aussi en epistemologie et en theorie de la verite, a consacree a l'Ecole de Lvov-Varsovie. (shrink)

One can often encounter an opinion that Polish scientific philosophy deserves to be much better known than actually is. This book is thought as a response to such a claim. The papers collected in this volume are divided into two parts: Background and Influence and History and Systematics. However, there is no sharp borderline between themes which are touched in both parts. Generally speaking, all papers of the first part relate the Lvov-Warsaw School to some philosophical movements external to it (...) whereas the papers collected in the second one focus on internal issues connected with the school . Since the Polish school of mathematical logic is much better known than the Polish analytic philosophy we decided to omit here any treatment of the former. Thus, this collection centers on purely philosophical matters. We projected this volume not as an exhaustive panorama of Polish analytic philosophy but rather as a series of essays on particular persons or topic. As a result one can find here papers on Twardowski. Ajdukiewicz, Kotarbinski, Tarski and Lukasiewicz as well as on ethics on science, nominalism, and the methodology of psychology. We hope that this book will contribute to a better knowledge and evaluation of Polish achievements in analytic philosophy. We would like to express our gratitude to Professor Leszek Nowak, the editor-in-chief of Poznan Studies in the Philosophy of the Sciences and the Humanities, who initiated the idea of the collection and helped in its preparation. (shrink)

Les Premiers Analytiques sont pour Lukasiewicz un livre de logique et non de philosophie. Il dit meme que cet ouvrage de pure logique ne contient aucune contamination philosophique. Mais cela ne veut pas dire qu'il n'a rien a apprendre aux philosophes et aux metaphysiciens sur les formalismes et sur les modalites. Comme le dit Lukasiewicz: Il reste encore des philosophes en activite auxquels il ne serait peut-etre pas impossible de suggerer qu'ils devraient acquerir une bonne connaissance de la (...) logique dite mathematique avant de traiter de la logique et de son histoire; ils eviteraient ainsi de perdre leur temps, leurs lecteurs de meme, ce qui n'est peut-etre pas denue d'importance pratique. Lukasiewicz est l'un des philosophes de l'Ecole de Lvov-Varsovie, courant philosophique majeur du XXe siecle. Son premier livre portait sur le principe de contradiction chez Aristote. Il en montrait l'importance, mais aussi la fragilite logique. Son dernier livre, consacre a la syllogistique, une partie de la logique, porte de nouveau sur Aristote. Pour peu qu'elle n'ignore pas Frege, les matrices logiques de Peirce, les Principia Mathematica de Russell et Whitehead ainsi que les apports considerables des logiciens polonais, comme Lesniewski, Sfupecki, et Lukasiewicz lui-meme, l'histoire de la logique, et en l'occurrence l'etude des Premiers Analytiques, constitue une voie d'acces privilegiee pour comprendre ce que sont les formalismes. (shrink)

Poland has played an enormous role in the development of mathematical logic. Leading Polish logicians, like Lesniewski, Lukasiewicz and Tarski, produced several works related to philosophical logic, a field covering different topics relevant to philosophical foundations of logic itself, as well as various individual sciences. This collection presents contemporary Polish work in philosophical logic which in many respects continue the Polish way of doing philosophical logic. This book will be of interest to logicians, mathematicians, philosophers, and linguists.

En 1910, Jan Lukasiewicz publiait Du principe de contradiction chez Aristote. Dans cet article, on explique les points principaux du livre de Lukasiewicz. Ce dernier affirme qu’Aristote n’a pas réussi dans sa tentative pour justifier le principe de contradiction. En fait, ce principe est moins logique qu’éthique, selon Lukasiewicz, et cela explique bien des difficultés posées par la théorie d’Aristote. On discute également de la façon dont Lukasiewicz utilise la notion d’« objets contradictoires », empruntée à (...) la Théorie des Objets de Meinong ; on montre que Lukasiewicz se situe dans le cadre d’une version brentanienne de l’aristotélisme. Certaines connexions entre Lukasiewicz et la conception wittgensteinienne de la nécessité ou le conservatisme logique de Quine sont indiquées. Le but de mon article est essentiellement d’encourager une lecture attentive du livre qui n’a pas reçu l’attention qu’il mérite parce qu’il a été écrit à l’origine en polonais. Souvent, les philosophes croient connaître son contenu à travers le résumé que Lukasiewicz écrivit en allemand en 1910, et qui a été traduit en anglais. Mais, en fait, il y a bien des choses importantes dans le livre qui n’apparaissent nullement dans le résumé.In 1910, Jan Lukasiewicz published On the Principle of Contradiction in Aristotle. In the present paper, I explain the main points in Lukasiewicz's book. Lukasiewicz claims that Aristotle was not successful in his attempt to justify the principle of contradiction. In fact, this principle is less logical than ethical, according to Lukasiewicz ; and this accounts for many of Aristotle's difficulties. Lukasiewicz's use of the notion of “contradictory objects”, taken from Meinong's Theory of Objects , is also discussed, and Lukasiewicz is shown to be situated within the Brentanian form of Aristotelism. I also indicate some connections between Lukasiewicz and Wittgenstein on necessity, and between Lukasiewicz and Quine on logical conservatism. The goal of the present paper is principally to encourage an attentive reading of a book that has not received the consideration it deserves because it was initially written in Polish. Often, philosophers believe that they grasp the content of the book through the brief abstract which Lukasiewicz wrote in German in 1910, and which has been translated into English ; but in fact there is much of importance which the abstract does not cover. (shrink)

English summary: Jan Lukasiewicz (1878-1956) was one of the most important members of the Lwow-Warsaw school of logic. The thirteen translated articles in this volume demonstrate the protean form of Lukasiewiczs work, from his texts on Aristotle and the principle of non-contradiction and syllogistics to modal logic, intuitionism, and multivalent logics. The articles show in particular his preoccupations with logical precision and the problem of human liberty. French description: Avec Kazimierz Twardowski, Stanislaw Lesniewski et Alfred Tarski, le logicien et (...) philosophe polonais Jan Lukasiewicz (1878-1956) est l'un des membres les plus importants de l'Ecole de Lvov-Varsovie. Celebre pour ses ouvrages consacres a Aristote, notamment sur le principe de non-contradiction et sur la syllogistique, il a egalement publie des articles majeurs sur la logique propositionnelle, la logique modale, l'intuitionnisme et les logiques multivalentes, dont il fut l'un des fondateurs. Enfin, il a contribue a faire reconnaitre l'importance des travaux en logique de l'ecole megarico-stoicienne, trop longtemps eclipses par ceux d'Aristote sur la syllogistique. Mais Lukasiewicz ne fut pas seulement un logicien et un historien brillant, il s'engagea aussi dans les polemiques philosophiques de son temps. Il defendit ainsi la methode logique en philosophie. Proche sur ce point des membres du Cercle de Vienne, il ne rejetait pas pour autant les questions metaphysiques, commecelle du determinisme qui l'occupa toute sa vie. Les treize articles de ce recueil, fruit d'un travail collectif de traduction, ont pour ambition de montrer le caractere proteiforme de l'oeuvre de Lukasiewicz, preoccupe autant par la precision logique que par le probleme de la liberte humaine. (shrink)

Jan Lukasiewicz's treatise on Aristotle's Syllogistic, published in the 1950s, has been very influential in framing contemporary understanding of Aristotle's logical systems. However, Lukasiewicz's interpretation is based on a number of tendentious claims, not least, the claim that the syllogistic was intended to apply only to non-empty terms. I show that this interpretation is not true to Aristotle's text and that a more coherent and faithful interpretation admits empty terms while maintaining all the relations of the traditional square (...) of opposition. (shrink)

In 1951 Lukasiewicz [[sic]] linked Aristotle's Prior Analytics with modern formal logic. This book attempts to analyze Aristotle's syllogistic theory in the light of Lukasiewcz's work and the whole tradition of classic interpretations of Aristotle's logic. The first of the book's five chapters shows that for Aristotle the syllogism is basically a relationship of terms couched in conditional form; a relationship of variables rather than concrete terms; and a relationship that sees S linked with P not by the copula (...) but by less metaphysical expressions. The classical S is P form is not Aristotelian at all but a much later renovation. The second chapter maintains that Aristotle distinguishes "relative necessity" from "absolute necessity." Aristotle himself ignores his own distinction at times and thus creates logical difficulties for himself. The oft-fought sea battle is fought again in this chapter. Chapter three deals with the controversial notions of "perfect" and "imperfect" syllogisms. The author asserts that by "perfect syllogism" Aristotle means self-evident syllogisms that serve as axioms for deducing other proofs. Chapters four and five deal with the figures of the syllogism and the syllogism as a deductive system respectively. Patzig concludes that Aristotle's syllogistic theory is purely formal in its structure and can only be properly understood if it is not tied to a metaphysics and converted into a philosophical logic. He denies that it is a universal logic, but rather sees it as a specialized theory of relations.--J. J. R. (shrink)

Publicado originalmente em 1974, este breve artigo de John Corcoran analisa algumas passagens da obra de Jan Lukasiewicz dedicada à silogística de Aristóteles, refutando a tese do lógico polonês de que os silogismos aristotélicos seriam condicionais universalizados.

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)

JUNE 2015 UPDATE: A BIBLIOGRAPHY: JOHN CORCORAN’S PUBLICATIONS ON ARISTOTLE 1972–2015 By John Corcoran -/- This presentation includes a complete bibliography of John Corcoran’s publications relevant to his research on Aristotle’s logic. Sections I, II, III, and IV list 21 articles, 44 abstracts, 3 books, and 11 reviews. It starts with two watershed articles published in 1972: the Philosophy & Phenomenological Research article from Corcoran’s Philadelphia period that antedates his Aristotle studies and the Journal of Symbolic Logic article from his (...) Buffalo period first reporting his original results; it ends with works published in 2015. A few of the items are annotated as listed or with endnotes connecting them with other work and pointing out passages that in-retrospect are seen to be misleading and in a few places erroneous. In addition, Section V, “Discussions”, is a nearly complete secondary bibliography of works describing, interpreting, extending, improving, supporting, and criticizing Corcoran’s work: 8 items published in the 1970s, 23 in the 1980s, 42 in the 1990s, 56 in the 2000s, and 69 in the current decade. The secondary bibliography is also annotated as listed or with endnotes: some simply quoting from the cited item, but several answering criticisms and identifying errors. Section VI, “Alternatives”, lists recent works on Aristotle’s logic oblivious of Corcoran’s research and, more generally, of the Lukasiewicz-initiated tradition. As is evident from Section VII, “Acknowledgements”, Corcoran’s publications benefited from consultation with other scholars, most notably Timothy Smiley, Michael Scanlan, Roberto Torretti, and Kevin Tracy. All of Corcoran’s Greek translations were done in collaboration with two or more classicists. Corcoran never published a sentence without discussing it with his colleagues and students. -/- REQUEST: Please send errors, omissions, and suggestions. I am especially interested in citations made in non-English publications. Also, let me know of passages I should comment on. (shrink)

The Actual and the Possible presents new essays by leading specialists on modality and the metaphysics of modality in the history of modern philosophy from the seventeenth to the twentieth centuries. It revisits key moments in the history of modern modal doctrines, and illuminates lesser-knownmoments of that history. The ultimate purpose of this historical approach is to contextualise and even to offer some alternatives to dominant positions within the contemporary philosophy of modality. Hence the volume contains not only new scholarship (...) on the early-modern doctrines of Baruch Spinoza,G. W. F. Leibniz, Christian Wolff and Immanuel Kant, but also work relating to less familiar nineteenth-century thinkers such as Alexius Meinong and Jan Lukasiewicz, together with essays on celebrated nineteenth- and twentieth-century thinkers such as G. W. F. Hegel, Martin Heidegger and BertrandRussell, whose modal doctrines have not previously garnered the attention they deserve. The volume thus covers a variety of traditions, and its historical range extends to the end of the twentieth century, addressing the legacy of W. V. Quine's critique of modality within recent analyticphilosophy. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:New Light from Arabic Sources on Galen and the Fourth Figure of the Syllogism NICHOLAS RESCHER The Problem of the Origin of the Fourth Figure FLYING IN THE FACE of the long-standing tradition--going back in Europe to Renaissance times--which credits Galen of Pergamon with the origination of the fourth syllogistic figure, recent authorities have almost to a man evinced doubt about Galen's claim to this innovation. Heinrieh Scholz speaks (...) of "the Galenian syllogistic figure which has been attributed to him, probably wrongly." i j. W. Stakelum concludes his careful discussion of the matter with the categorical assertion that "Galen did not teach the fourth figure." ~ I. M. Bochenski--following Lukasiewicz (see below)--says that the fourth figure "was only ascribed to Galen by a misunderstanding." : William Kneale (also following Lukasiewicz) writes that "it is easy to see how misunderstanding.., by some Arabian philosopher... could have given rise to the tradition that Galen added a fourth figure to Aristotle's syllogistic theory." 4 The currently received account of the matter is that of Jan Lukasiewicz who, in his book on Aristotle's Syllogistic (1951; 2d ed., 1957), presents the known reports about Galen and the fourth figure as follows (I list them in the order in which they came to light) : 1) Several passages in Averroes' (d. 1198) Middle Commentary on Prior Analytics credit Galen with introducing a fourth figure (ad Anal. Pr. I, 5; I, 8; I, 23). These passages, known in Europe through a Renaissance Latin translation of a Hebrew version, provided the basis upon which Zabarella in his work, De Quarta Syllogismorum Figura (in his Opera [Leiden: 1587], pp. 41-53), popularized the "Galenian figure" in European logic. 2) In 1844 Minoides Mynas published in the Preface to his edition of Galen's EisagSg~ dialektik~ an anonymous Greek fragment (late, perhaps 6th century) which states that certain "later scholars" transformed the indirect moods of the first figure added by Theophrastus and Eudeffms into a new fourth figure, citing Galen as the originator of this doctrine.~ 1Abriss der Geschichte der Logik (Miinster: 1931), trans, into English by K. F. Leidecker, ConciseHistory of Logic (NewYork: 1961);p. 38ofthe Englishversion. "Why 'Galenian' Figure?" The New Scholasticism, XVI (1942),289-296. s Formale Logik (Miinchen-Freiburg:1956; 2nd. ed., 1962), trans, into English by Ivo Thomas, A History of Formal Logic (Notre Dame: 1961);p. 142of the Englishversion. Williamand Martha Kneale, The Developmentof Logic (Oxford: 1962),p. 184. Alsoprinted in Karl Kalbfieisch, ~ber Galen s Einleitung in die Logik, 2~. Supplementband der Jahrbi~cherfi~r klassische Philologie (Leipzig:1897), p. 707. This datum casts some 28 HISTORY OF PHILOSOPHY 3) A Greek fragment was found around 1858 by Karl Prantl in a logical work of the Byzantine scholar Ioannes Italus (llth century) which says that Galen taught the existence of a fourth figure, adding sarcastically that he (Galen) thought thus to appear cleverer than the older logical commentators (presumably Theophrastus and Eudemus are intended), but fell far short.6 4) In 1899 Maximilian Wallies published7 an anonymous Greek scholium (of perhaps the 6th or the 7th century) on Ammonins' commentary on Prior Analytics which states that Galen "says in his Apodictic that there are four figures, because he looks at the compound syllogisms consisting of four terms (i.e., with three premisses )" rather than the simple (three-term, two-premiss) syllogisms of Aristotle. (The scholiast goes on to explain at some length how such compound syllogisms can be sorted into four groups.) It is readily seen that, given these data, two possibilities stand before us: a) Galen did actually invent the traditional fourth figure. Reports (1)-(3) are correct, and the anonymous scholiast of (4) was put on the wrong track by the fact that Galen also said that compound syllogisms of four terms can be classed into four groups. b) Galen did not invent the traditional fourth figure. Only after his time when once the indirect moods of the first figure had--somehow--become systematized into a separate "figure," was this credited to Galen by a mistake along the lines described by the anonymous scholiast. Thus (4) alone is right, and (1)-(3) are mistaken. Which of... (shrink)

The text of the treatise “The Propositional Logic of Boethius” was finished in 1939. Prof. Jan Lukasiewicz wished at that time to issue it in the second volume of “Collectanea Logica”; as a result of political events, he was not able to carry out his plan. In 1938, I published an article in “Erkenntnis” entitled “AUS- sagenlogik im Mittelalter”; this article included the contents of a paper which I read to the International Congress for the Unity of Science in (...) Cambridge, England, in 1938 (Cf. Erkenntnis, vol. 7, pp. 160-168). The subject matter of this paper touched upon that of the above-mentioned treatise. Recently an article of Mr. Rend van den Driessche, “Sur le ‘de syllogismo hypothetico’ de Boece”, was published in the journal “methodos” (vol. I, no. 3). Mr. van den Driessche referred in this article to the article on propositional logic in the middle ages, which had appeared in “Erkenntnis”. This reminded me of my yet-unpublished treatise on the propositional logic of Boethius. (shrink)

The purpose of this dissertation is to provide a defence of Aristotle's principle of contradiction against the critique made on it by Jan Lukasiewicz in an article he wrote in 1910 which was translated and published in the March 1971 number of The Review of Metaphysics. Lukasiewicz maintains in general that the law of contradiction has no logical worth. Specifically, he charges Aristotle with having several laws of contradiction instead of one as Aristotle claims; with attempting to prove (...) the law despite his claim that this is impossible and finally with failing in the very attempt to prove the law, or at least one of its formulations. In 20 chapters, each dealing with a respective section of Lukasiewicz's article, I attempt to show that all of Lukasiewicz's allegations are unfounded. My methodology is simply to follow Lukasiewicz through his 20 sections and compare what he says with what Aristotle actually wrote. If successful, this dissertation will show, in basic agreement with Professor Joseph Owens, that the best way to read Aristotle is on his own terms and not, as in the case of Lukasiewicz, via the latest developments in symbolic logic. I reiterate, with Aristotle, that the law of contradiction is the basic principle of being qua being and has logical worth precisely because of that fact. (shrink)