At Prior Analytics II 22.68a16–21, Aristotle argues that if A is predicated of all B and C and nothing else, and B is predicated of all C, then A and B convert. In justifying his argument, however, he appears to claim that B is not predicated of all A. This claim has long been a cause of puzzlement to commentators. A widespread view is that the kind of conversion discussed in the passage at issue should be explained in (...) both extensional and intensional terms. After providing some textual evidence that Aristotle only apparently claims that B is not predicated of all A, I give a purely extensional account of Aristotle’s argument. This account is plausible, conservative and simpler than any of the intensional accounts that have been proposed so far. (shrink)

This study contains three parts. The first tries to follow the spread of the study of the Prior Analytics in the first two centuries during which it was at all studied in Western Europe, providing in this connection a non-exhaustive list of extant commentaries. Part II points to a certain overlap between commentaries on the Prior Analytics and works from the genre of sophismata . Part III lists the questions discussed in a students' compendium from about (...) the 1240s and in six commentaries per modum quaestionis from the 1270s through the 1290s. (shrink)

Aristotle's Prior Analytics marks the beginning of formal logic. For Aristotle himself, this meant the discovery of a general theory of valid deductive argument, a project that he had described as either impossible or impracticable, probably not very long before he actually came up with syllogistic reasoning. A syllogism is the inferring of one proposition from two others of a particular form, and it is the subject of the Prior Analytics. The first book, to which this (...) volume is devoted, offers a fairly coherent presentation of Aristotle's logic as a general theory of deductive argument. (shrink)

Translation of the initial chapters of Aristotle’s Prior Analytics into Portuguese and introduction, which addresses interpretative disagreements and translation choices.

WE must first state the subject of our inquiry and the faculty to which it belongs: its subject is demonstration and the faculty that carries it out demonstrative science.

The reception history of Aristotle's Prior Analytics in the Islamic world began even before its ninth-century translation into Arabic. Three generations earlier, Arabic authors already absorbed echoes of the varied and extensive logical teaching tradition of Greek- and Syriac-speaking religious communities in the new Islamic state. Once translated into Arabic, the Prior Analytics inspired a rich tradition of logical studies, culminating in the creation of an independent Islamic logical tradition by Ibn Sina (d. 1037), Ibn Rušd (...) (d. 1098) and others. This article traces the translation and commentary tradition of the Prior Analytics in Syriac and Arabic in the sixth to ninth centuries and sketches its appropriation, revision and, ultimately, transformation by Islamic philosophers between the ninth and eleventh centuries. (shrink)

In Prior Analytics I.30, Aristotle seems too much optmistic about finding out the principles of sciences. For he seems to say that, if our empirical collection of facts in a given domain is exhaustive or sufficient, it will be easy for us to find out the explanatory principles in the domain. However, there is a distance between collecting facts and finding out the explanatory principles in a given domain. In this paper, I discuss how the key expression in (...) the sentence at 46a25 should be interpreted: “the true characteristics of things” (“τῶν ἀληθῶς ὑπαρχόντων τοῖς πράγμασιν”). I argue that, on a more accurate interpretation of the expression, Aristotle’s point would cease to look like a piece of naïve or even silly optimism. (shrink)

Prior Analytics by the Greek philosopher Aristotle (384 – 322 BCE) and Laws of Thought by the English mathematician George Boole (1815 – 1864) are the two most important surviving original logical works from before the advent of modern logic. This article has a single goal: to compare Aristotle’s system with the system that Boole constructed over twenty-two centuries later intending to extend and perfect what Aristotle had started. This comparison merits an article itself. Accordingly, this article does (...) not discuss many other historically and philosophically important aspects of Boole’s book, e.g. his confused attempt to apply differential calculus to logic, his misguided effort to make his system of ‘class logic’ serve as a kind of ‘truth-functional logic’, his now almost forgotten foray into probability theory, or his blindness to the fact that a truth-functional combination of equations that follows from a given truth-functional combination of equations need not follow truth-functionally. One of the main conclusions is that Boole’s contribution widened logic and changed its nature to such an extent that he fully deserves to share with Aristotle the status of being a founding figure in logic. By setting forth in clear and systematic fashion the basic methods for establishing validity and for establishing invalidity, Aristotle became the founder of logic as formal epistemology. By making the first unmistakable steps toward opening logic to the study of ‘laws of thought’—tautologies and laws such as excluded middle and non-contradiction—Boole became the founder of logic as formal ontology. (shrink)

It has often been claimed that (i) Aristotle's expression 'protasis' means 'premiss' in syllogistic contexts and (ii) cannot refer to the conclusion of a syllogism in the Prior Analytics. In this essay we produce and defend a counter-example to these two claims. We argue that (i) the basic meaning of the expression is 'proposition' and (ii) while it is often used to refer to the premisses of a syllogism, in Prior Analytics 1.29, 45b4-8 it is used (...) to refer to the conclusion of a syllogism. In our view, the best explanation of Aristotle's use of the expression 'protasis' is that it means proposition throughout but is frequently used without change of meaning (in certain specific contexts) to refer to the premisses from which a conclusion follows. In Prior Analytics 1.29, 45b4-8 he uses 'protasis' to refer to the conclusion when he needs a single expression to refer to both the conclusion and one of the premisses of the syllogism that constitutes the core of a syllogism through the impossible. If we are correct, we have shown that the view that the expression 'the final protasis' in EN 7.3, 1147b9ff must mean 'the final premiss' and so cannot refer to the conclusion of the relevant syllogism is mistaken. (shrink)

Since at least late antiquity, Aristotle’s Prior Analytics B 23 has been misread. Aristotle does not think that an induction is a syllogism made good by complete enumeration. The confusion can be eliminated by considering the nature of the surviving text and watching very closely Aristotle’s moving back and forth between “induction” and “syllogism from induction.” Though he does move freely between them, the two are not synonyms.

The Prior Analytics marks the beginning of formal logic, and is one of the most influential works in the history of thought. It is here that Aristotle sets out his system of syllogistic reasoning. The first book, to which this volume is devoted, offers a coherent presentation of Aristotle's logic as a general theory of deductive argument.

Prior Analytics by the Greek philosopher Aristotle and Laws of Thought by the English mathematician George Boole are the two most important surviving original logical works from before the advent of modern logic. This article has a single goal: to compare Aristotle's system with the system that Boole constructed over twenty-two centuries later intending to extend and perfect what Aristotle had started. This comparison merits an article itself. Accordingly, this article does not discuss many other historically and philosophically (...) important aspects of Boole's book, e.g. his confused attempt to apply differential calculus to logic, his misguided effort to make his system of ‘class logic’ serve as a kind of ‘truth-functional logic’, his now almost forgotten foray into probability theory, or his blindness to the fact that a truth-functional combination of equations that follows from a given truth-functional combination of equations need not follow truth-functionally. One of the main conclusions is that Boole's contribution widened logic and changed its nature to such an extent that he fully deserves to share with Aristotle the status of being a founding figure in logic. By setting forth in clear and systematic fashion the basic methods for establishing validity and for establishing invalidity, Aristotle became the founder of logic as formal epistemology. By making the first unmistakable steps toward opening logic to the study of ‘laws of thought’—tautologies and laws such as excluded middle and non-contradiction—Boole became the founder of logic as formal ontology.… using mathematical methods … has led to more knowledge about logic in one century than had been obtained from the death of Aristotle up to … when Boole's masterpiece was published.Paul Rosenbloom 1950. (shrink)

I argue that, in the Prior Analytics, higher and above the well-known ‘reduction through impossibility’ of figures, Aristotle is resorting to a general procedure of demonstrating through impossibility in various contexts. This is shown from the analysis of the role of adunaton in conversions of premises and other demonstrations where modal or truth-value consistency is indirectly shown to be valid through impossibility. Following the meaning of impossible as ‘non-existent’, the system is also completed by rejecting any invalid combinations (...) of terms in deductions or conversions. The notion of impossibility reaches the core of Aristotle's system in the Prior Analytics. On the one hand, the use of adunaton shows that he is following one of the two requisites for demonstrative science formulated in the Posterior Analytics, i.e. to demonstrate that it is impossible for things to be otherwise than stated. On the other hand, that demonstrations through impossibility are rooted in the notion of contradiction supp.. (shrink)

In Prior Analytics 1.15, Aristotle attempts to give a proof through the impossible of Barbara, Celarent, Darii, and Ferio with an assertoric first premiss, a contingent second premiss, and a possible conclusion. These proofs have been controversial since antiquity. I shall show that they are valid, and that Aristotle is able to explain them by relying on two meta-syllogistic lemmas on the nature of possibility interpreted as syntactic consistency. It will turn out that Aristotle's proofs are not of (...) the intended schemata. I shall investigate some of the results that the impact of this reconstruction on the modal syllogistic has: the relationship between Aristotle's syllogistic and the logics of relevance; the value of Aristotle's requirement that universal affirmative propositions be taken ‘absolutely’; the destruction of many Aristotelian proofs; the recovery of certain principles of modal opposition from a charge of inconsistency. (shrink)

A study of the reception of Aristotle's Prior Analytics in the first half of the twelfth century. It is shown that Peter Abaelard was perhaps acquainted with as much as the first seven chapters of Book I of the Prior Analytics but with no more. The appearance at the beginning of the twelfth century of a short list of dialectical loci which has puzzled earlier commentators is explained by noting that this list formalises the classification of (...) extensional relations between general terms and that this classification had already be put forward by Boethius in his de Syllogismo Categorico and Introductio ad Syllogismos Categoricas . It is pointed out the kind of text referred to as an ` Introductio ' at the beginning of the twelfth-century follows very closely the structure of Boethius own Introductio and adds to it material drawn from his accounts of loci and the conditional propositions. It is argued that the reception of the Prior Analytics has to be understood against the background of this well developed tradition of treating together syllogisms, loci , and conditional propostions. Referring to a challenge to the formal validity of Darapti in the Ars Meliduna the paper concludes by illustrating that the theory of the syllogism presented in Prior Analytics was still controversial in the middle of the twelfth-century. (shrink)

It has often been claimed that Aristotle’s expression ‘protasis’ means ‘premiss’ in syllogistic contexts and cannot refer to the conclusion of a syllogism in the Prior Analytics. In this essay we produce and defend a counter-example to these two claims. We argue that the basic meaning of the expression is ‘proposition’ and while it is often used to refer to the premisses of a syllogism, in Prior Analytics 1.29, 45b4-8 it is used to refer to the (...) conclusion of a syllogism. In our view, the best explanation of Aristotle’s use of the expression ‘protasis’ is that it means proposition throughout but is frequently used without change of meaning to refer to the premisses from which a conclusion follows. In Prior Analytics 1.29, 45b4-8 he uses ‘protasis’ to refer to the conclusion when he needs a single expression to refer to both the conclusion and one of the premisses of the syllogism that constitutes the core of a syllogism through the impossible. If we are correct, we have shown that the view that the expression ‘the final protasis’ in EN 7.3, 1147b9ff must mean ‘the final premiss’ and so cannot refer to the conclusion of the relevant syllogism is mistaken. (shrink)

In Prior Analytics 1.27–30, Aristotle develops a method for finding deductions. He claims that, given a complete collection of facts in a science, this method allows us to identify all demonstrations and indemonstrable principles in that science. This claim has been questioned by commentators. I argue that the claim is justified by the theory of natural predication presented in Posterior Analytics 1.19–22. According to this theory, natural predication is a non-extensional relation between universals that provides the metaphysical (...) basis for demonstrative science. (shrink)

I reconstruct Aristotle’s analytical procedure in Prior Analytics I.45 and its metalogical implications. Aristotle’s analysis unfolds three groups of syllogisms: symmetrically analysable, asymmetrically analysable, and non-analysable syllogisms. From the first and the third group could be extracted 27 combinations of the two mutually non-derivable deductive rules. Aristotle’s reduced deductive system in APr. I.7 with the two moods in the first figure (traditionally called Barbara and Celarent) follows this pattern. I demonstrate that the deductive system with Barbara and Celarent (...) is just one of 27 possible complete deductive systems with the two mutually non-derivable syllogistic rules. On top of that, given the fact that there are two combinations of mutually non-derivable conversion rules, I conclude that Prior Analytics hides in itself 54 complete deductive systems with a minimal number of mutually non-derivable rules. Finally, it is commented what might be the role of analysis; to what extent Aristotle could be aware of possibilities presented here; why he still prefers only one deductive system to many others with the same deductive power. (shrink)

This study contributes substantially to research on Aristotelian logic in Byzantium. It includes a critical edition of the commentary by Leo Magentenos, the Metropolitan of Mytilene (twelfth c.?) on Book II of the Prior Analytics along with an edition of the syllogism diagram attributed to this work in the manuscript tradition of this work.

Aristotle’s modal syllogistic is his study of patterns of reasoning about necessity and possibility. Many scholars think the modal syllogistic is incoherent, a ‘realm of darkness’. Others think it is coherent, but devise complicated formal modellings to mimic Aristotle’s results. This volume provides a simple interpretation of Aristotle’s modal syllogistic using standard predicate logic. Rini distinguishes between red terms, such as ‘horse’, ‘plant’ or ‘man’, which name things in virtue of features those things must have, and green terms, such as (...) ‘moving’, which name things in virtue of their non-necessary features. By applying this distinction to the Prior Analytics, Rini shows how traditional interpretive puzzles about the modal syllogistic melt away and the simple structure of Aristotle’s own proofs is revealed. The result is an applied logic which provides needed links between Aristotle’s views of science and logical demonstration. The volume is particularly valuable to researchers and students of the history of logic, Aristotle’s theory of modality, and the philosophy of logic in general. (shrink)

Since Peter Geach coined the phrase in 1966 there has been much discussion among scholars of the "Socratic fallacy." No consensus presently exists on whether Socrates commits the "Socratic fallacy"; almost all scholars agree, however, that the "Socratic fallacy" is a bad thing and that Socrates has good reason to avoid it. I think that this consensus of scholars is mistaken. I think that what Geach has labeled a fallacy is no fallacy at all, but a perfectly innocent consequence of (...) Platonic epistemology. The "Socratic fallacy" arises from the "Priority of Definition" principle (PD). Plato is committed to (PD) in the "Meno." The "Meno" also contains a famous discussion of the difference between episteme and doxa (97a ff.). If we understand what Plato meant by episteme we can see that he must be committed to (PD); but we can also see that (PD) has none of the harmful consequences Geach attributes to it. Geach's view is indebted to Wittgenstein's philosophy of language. (PD) is implausible on this reading of the verb "to know," but not on Plato's. Plato claims that a demand for an explanation is appropriate wherever a claim to knowledge is made. Plato links the concept of episteme explicitly with the concept of logos; the connection between the terms may have been analytic. It does not follow from the Platonic conception of knowledge, as Geach argues, that it is "no use" using examples to establish general definitions. All that follows is that one cannot know that an alleged example of a term T is a genuine example until one has a general account of what it is to be T. Without the stronger conclusion, Geach cannot establish that the "Socratic fallacy" is a fallacy. (shrink)

In the second half of Book One of the Prior Analytics, Aristotle reflects on the application of the formalized logic has developed in the first half, focusing particularly on the non-modal or assertoric syllogistic developed in the first seven chapters. These reflections lead Alexander of Aphrodisias, who was a great exponent of Aristotelianism in the late second century, to explain and sometimes argue against subsequent developments of Aristotle's logic and alternatives and objections to it, ideas associated mainly with (...) his colleague Theophrastus and with the Stoics. The other main topic of this part of the Prior Analytics is the specification of a method for discovering true premises needed to prove a given proposition. Aristotle's presentation is sometimes difficult to follow, and Alexander's discussion is extremely helpful to the uninitiated reader. In his commentary on the final chapter translated in this volume, Alexander provides an insightful account of Aristotle's criticism of Plato's method of division. (shrink)

The last 14 chapters of book 1 of Aristotle's "Prior Analytics" are concerned with the representation in the formal language of syllogistic of propositions and arguments expressed in more or less everyday Greek. In his commentary on those chapters, Alexander of Aphrodisias explains some of Aristotle's more opaque assertions and discusses post-Aristotelian ideas in semantics and the philosophy of language. In doing so he provides an unusual insight into the way in which these disciplines developed in the Hellenistic (...) era. He also shows a more sophisticated understanding of these fields than Aristotle himself, while remaining a staunch defender of Aristotle's emphasis on meaning as opposed to Stoics concern with verbal formulation. In his commentary on the final chapter of book 1 Alexander offers a thorough discussion of Aristotle's distinction between denying that something is, e.g., white and asserting that it is non-white. (shrink)

The present paper aims to show that the reconstruction of the formal framework of the proofs in Pr. An. 1.15, as proposed by Malink and Rosen 2013 (‘Proof by Assumption of the Possible in Prior Analytics 1.15’, Mind, 122, 953-85) is due to affront a double impasse. Malink and Rosen argue convincingly that Aristotle operates with two different modal frameworks, one as found in the system of modal logic presented in Prior Analytics 1.3 and 8-22, and (...) one occurring in many of Aristotle’s works, such as the Physics, De Caelo and the Metaphysics. However, they misconstrue the latter framework. More precisely, they misconstrue the domain of significance of what they call the ‘Principle of Necessitation’. As a consequence, bringing the two frameworks into one results into a contradictory modal logic. On the other hand, if the Principle of Necessitation is rectified, the proofs put forward by Malink and Rosen in the same paper are no longer available. (shrink)

All the way through An.Pr. A9 11, Aristotle gives a new and separate proof of each modal syllogism. He does not take the mixed syllogisms as entirely trivial and obvious. He tries to explain them and to establish their validity. And that is where ...

Studies of Aristotle’s syllogistic system, since Corcoran’s deductionist interpretation supplanted Łukasiewicz’ axiomaticist interpretation, misrepresent Aristotle’s logic in two important respects. Following Corcoran, they take indirect deduction to occur only once in a deduction discourse; they then obviate the system having a reductio rule. Second, they represent reduction as a deductive process for deriving ‘imperfect’ syllogisms from ‘perfect’ syllogisms to impose an axiomatic interpretation on the logic. Denying that Aristotle's logic admits of a reductio rule results from this misrepresentation of reduction. (...) This discussion shows that the defects imputed to Aristotle's logic, and systems devised to resolve them, result from misunderstanding reduction, which itself results from misapprehending Prior Analytics expressly to identify in a metadiscourse deduction rules and not deductions per se. (shrink)

Aristotle studies syllogistic argumentation in Sophistical Refutations and Prior Analytics. In the latter he focuses on the formal and syntactic character of arguments and treats the sullogismoi and non-sullogismoi as argument patterns with valid or invalid instances. In the former Aristotle focuses on semantics and rhetoric to study apparent sullogismoi as object language arguments. Interpreters usually take Sophistical Refutations as considerably less mature than Prior Analytics. Our interpretation holds that the two works are more of a (...) piece than previously believed and, indeed, that Aristotle's treatment of fallacious reasoning presupposes the results of the formal theory. (shrink)

Die Quellen der Aristoteles-Rezeption bzw. der aristotelischen Logik im byzantinischen Mittelalter sind nur teilweise oder gering erforscht. Eine der wichtigen Autoritäten dieser Tradition stellt Leon Magentenos (12. Jh.?) dar. Magentenos war Metropolit von Mytilene sowie ein Gelehrter, der Kommentare zu allen sechs Traktaten des aristotelischen Organon (Categoriae, De Interpretatione, Analytica Priora, Analytica Posteriora, Topica, Sophistici Elenchi) verfasst hat. Hier wird die kritische Edition des Kommentars zum zweiten Buch der Ersten Analytik zusammen mit seiner Übersetzung ins Englische vorgelegt. Untersucht werden auch (...) die dem Kommentar angehängten syllogistischen Diagramme. Kommentare zu Analytica Priora II nach der Spätantike und vor Magentenos waren eher eine Rarität, daher ist sein Kommentar eine wichtige Quelle für alle Forscher, die sich mit der Geschichte der byzantinischen Logik und der aristotelischen Kommentierung befassen. (shrink)

In previous issues of The Review of Metaphysics attention has been drawn to the project of Professor Richard Sorabji to publish the English translations of the ancient Greek commentators of Aristotle. We are happy to present a new volume of this series which contains the English translation of the commentary by Alexander of Aphrodisias on Aristotle’s Prior Analytics, I, chapters 8–13. In his preface Professor Sorabji underlines the importance of Alexander’s commentary on these chapters, in which Aristotle invented (...) modal syllogistic. This volume comprises the commentary on chapters 8 to 13. Chapters 1, 2, and 4 to 7 contain Aristotle’s assertoric syllogistic. For Alexander’s commentary on these chapters the translators refer to the excellent edition of Jonathon Barnes, et al. In chapters 8 to 13 Aristotle studies syllogisms which consist of two necessary propositions and those which are composed of one necessary proposition and a second which is modally unqualified. The central question is which modal syllogisms, analogous to assertoric syllogisms of the first figure, are true syllogisms. The translators have added Alexander’s commentary on chapter 17, where it is argued that a privative contingent proposition cannot be converted into a syllogism of the first figure. (shrink)

This paper examines the relevance and importance of the large number of examples which Aristotle uses in his "Prior Analytics." In the first part of the paper three preliminary issues are raised: First, it investigates what counts as an example in Aristotle's syllogistic, and especially whether only examples expressed in concrete terms should be considered as examples or maybe also propositions and arguments with letters of the alphabet. The second issue concerns the kinds of examples Aristotle actually uses (...) from everyday life as well as from various scientific and philosophical forms of discourse; among these, it seems that biological examples, rather than mathematical ones, have a predominant place. Finally, I discuss what Aristotle himself has to say about the use of examples, and in particular about the similarity between the use of an example and the use of induction. The second part of the paper focusses on the functions of Aristotle's logical examples. It is of course obvious that some of the examples in the Prior Analytics are used to illustrate, and thus to clarify, a definition, a logical rule, a type of argument. However, I think that Aristotle's logical examples have another function, which is philosophically more interesting, namely as integral parts of the procedure of proving something. To support this claim, I analyse three passages from the "Prior Analytics" in which examples are used either in order to prove that something is not the case, i.e. as counter-examples, or in order to prove positively that it is possible for something to be the case. At the end, I argue that for such uses of examples Aristotle uses the notion of 'ekthesis', which seems to have a wider sense than usually suggested; that is to say, it is used to refer to any proof by means of an example, and not only for the procedure which Aristotle uses to reduce imperfect to perfect syllogisms. (shrink)

During the years 800-1200 A.D., Arabic scholars studied many of the works of Greek philosophy, and recorded their interpretations. Significant Arabic interpretations of Aristotle's Prior Analytics, the key work of his logical Organon, however, have remained largely unavailable in the West. The recent discovery of several Arabic manuscripts in Istanbul revealed the “Short Commentary on Prior Analytics” by the medieval Arabic philosopher al-Farabi. Nicholas Rescher here presents the first translation of this work in English, and supplements (...) this with an informative introduction and numerous explanatory footnotes. (shrink)

In Prior Analytics 1.15 Aristotle undertakes to establish certain modal syllogisms of the form XQM. Although these syllogisms are central to his modal system, the proofs he offers for them are problematic. The precise structure of these proofs is disputed, and it is often thought that they are invalid. We propose an interpretation which resolves the main difficulties with them: the proofs are valid given a small number of intrinsically plausible assumptions, although they are in tension with some (...) claims found elsewhere in Aristotle’s modal syllogistic. The proofs make use of a rule of propositional modal logic which we call the possibility rule. We investigate how this rule interacts and coheres with the core elements of the modal syllogistic. (shrink)