Avicenna (d. 1037) and Tūsī (d. 1274) have different doctrines on the contradiction and conversion of the absolute proposition. Following Avicenna's presentation of the doctrine in Pointers and reminders, and comparing it with what is given in Tūsī's commentary, allow us to pinpoint a major reason why Avicenna and Tūsī have different treatments of the modal syllogistic. Further comparison shows that the syllogistic system Rescher described in his research on Arabic logic more nearly fits Tūsī than Avicenna. This in turn (...) has consequences for analysing Avicenna's logic, and for writing the history of a fascinating period of change and diversity in the discipline in the medieval Islamic world. (shrink)

This paper examines al-Fārābī's logical thought within its Arabico-Islamic historical background and attempts to conceptualize what this background contributes to his logic. After a brief exposition of al-Fārābī's main problems and goals, I shall attempt to reformulate the formal structure of Arabic linguistics (AL) in terms of the ontological and formal characteristics that Arabic logic is built upon. Having discussed the competence of al-Fārābī in the history of AL, I will further propose three interrelated theses about al-Fārābī's logic, in terms (...) of which I will attempt to redefine it: the logico-linguistic conception, the project of logicization, and nuclear logic. The final question that will arise is how Aristotle's logic could be built upon AL, which has a nature contrary to logic. The present paper also contributes to examining our traditional research habits in Arabic studies. (shrink)

In this article, the author studies some central concepts in Avicenna's and sī's modal logics as presented in Avicenna's Al-Ish r t wa'l Tan īh t ( Pointers and Reminders ) and in sī's commentary. In this work, Avicenna introduces some remarkable distinctions in order to interpret Aristotle's modal syllogistic in the Prior Analytics . The author outlines a new interpretation of absolute sentences as temporally indefinite sentences and argues on the basis of this that Avicenna seems to subscribe to (...) the Principle of Plenitude. He also shows that he has no valid proof of the modal conversion rules and that he uses some rather ad hoc distinctions to show that Aristotle's modal syllogistic is correct. The author also notes some interesting differences between Avicenna's and sī's approaches to modal logic. (shrink)

The article aims at demonstrating that in attributing the creatio ex nihilo to both Plato and Aristotle as their unanimous philosophical conviction the Treatise on the Harmony between the Two Sages deeply depends upon the Neoplatonic reading of those two philosophers. The main obstacles for such a view in the works of the two sages are Plato's assumption of a precosmic chaos in the Timaeus and Aristotle's denial of any efficient causality to the unmoved mover in the Metaphysics. Both of (...) these points had been, however, done away with by the Neoplatonist commentators already, especially by Ammonius in his lost treatise on efficient and final causality in Aristotle the use of which in the Harmony is shown by a comparison with Simplicius. Christian and Muslim readers just had to transfer those arguments and hermeneutical techniques into an anti-eternalist context in order to make the two philosophers agree with one of the basic tenents of their face, a hermeneutical technique considerably different from the one employed by al-Fārābī in his exposition of Plato's and Aristotle's philosophy which is compared to the Harmony in a briefly sketched concluding section.L'article vise à montrer que le Traité sur l'harmonie des deux sages, en attribuant la creatio ex nihilo à Platon et Aristote comme conviction philosophique commune, dépend profondément de la lecture néoplatonicienne de ces deux philosophes. Les obstacles principaux à une telle attribution dans les œuvres des deux sages sont, dans le Timée de Platon, l'affirmation d'un chaos précosmique et, dans la Métaphysique d'Aristote, la négation d'une causalité efficiente du premier moteur immobile. L'interprétation néoplatonicienne avait toutefois éliminé chacune de ces affirmations de la doctrine des deux maîtres, comme le montre en particulier le traité d'Ammonius sur la causalité finale et efficiente chez Aristote. Or, on peut montrer, par une comparaison avec Simplicius, que l’Harmonie faisait usage de ce traité. Les philosophes chrétiens et musulmans avaient ainsi la possibilité d'employer les mêmes arguments et méthodes herméneutiques pour établir une concordance entre les deux principales autorités philosophiques d'une part et une de leurs plus importantes convictions religieuses d'autre part – une herméneutique qui diffère considérablement de la méthode appliquée par al-Fārābī dans sa propre exposition des philosophies de Platon et d'Aristote, comme le montre, dans la conclusion de l'article, la brève comparaison avec l’Harmonie.Send article to KindleTo send this article to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle. Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply. Find out more about the Kindle Personal Document Service.CREATIO EX NIHILO – A GENUINELY PHILOSOPHICAL INSIGHT DERIVED FROM PLATO AND ARISTOTLE? SOME NOTES ON THE TREATISE ON THE HARMONY BETWEEN THE TWO SAGESVolume 22, Issue 1Benjamin Gleede DOI: https://doi.org/10.1017/S0957423911000117Your Kindle email address Please provide your Kindle [email protected]@kindle.com Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. 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Cancel Send ×Send article to Google Drive To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive. CREATIO EX NIHILO – A GENUINELY PHILOSOPHICAL INSIGHT DERIVED FROM PLATO AND ARISTOTLE? SOME NOTES ON THE TREATISE ON THE HARMONY BETWEEN THE TWO SAGESVolume 22, Issue 1Benjamin Gleede DOI: https://doi.org/10.1017/S0957423911000117Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Export citation Request permission. (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)

When questioning whether political deception can be ethically warranted, two competing intuitions jump to the fore. First, political deception is a fact of human life, used in the realpolitik of governance. Second, the ethical warrant of truth asserts itself as inexorably and indefatigably preferable to falsehood. Unfortunately, a cursory examination of the history of philosophy reveals a paucity of models to marry these basic intuitions. Some thinkers (e.g., Augustine, Aquinas, Grotius, Kant, Mill, and Rawls) privilege the truth by neglecting the (...) realpolitik, i.e., the truth is inviolate. Others (e.g., Machiavelli, Bentham, and the often infamous caché of 20th century dictators) focus upon the realpolitik to the exclusion of the primacy of the truth. A third group of critical thinkers (e.g., Arendt and Bok) examine the topic but offer no positive, systematic treatment of deception. Lacking are theories which simultaneously recognize that political untruth is often necessary, but that untruth is only justified when a) truth is politically impossible, b) the necessity of untruth is demonstrable, and c) the truth can be replaced with a minimally injurious untruth. Plato offers one such account in the Republic, arguing that deceit must be applied medicinally to the city. However, his account is problematic in detail. One of Plato’s inheritors, the 10th century thinker al-Fārābī, advanced Plato’s theoretical account, arguing that political governance requires restrained political deception. This deception, the expression of philosophical truths through the symbols of religion, meets the criteria mentioned above, being necessary, demonstrably necessary, and minimally injurious. But while al-Fārābī provides a valuable model for what justified political deception could look like, the lengths to which he must go in order to create a viable model for political deception reveals the untenability of the notion of justified political deception writ large. One must orchestrate an entire cosmos around the notion, notably a cosmos that does not match our own. One must adopt very specific conceptions of human nature, association, and happiness, as well as a particular metaphysics and epistemology. For, while al-Fārābī shows that political deception can be justifiable, he also reveals its unjustifiability outside an idealized setting. (shrink)

Al-Ghazālı̄ famously claims in the Incoherence of the Philosophers that al-Fārābī and Avicenna are unbelievers because they hold philosophical positions that conflict with Islam. What is less well-known, however, is that Averroës claims in the Decisive Treatise that al-Fārābī and Avicenna are not unbelievers; rather, al-Ghazālı̄ is the true unbeliever for writing the Incoherence of the Philosophers. In this paper, my aim is to present a sustained reconstruction of Averroës’ legal and philosophical argument for why al-Ghazālı̄ is an unbeliever. The (...) crux of Averroës’ argument is that al-Ghazālı̄ has expressed false allegorical interpretations of scripture to unqualified persons, which has led them into unbelief. By being causally responsible for other people’s unbelief, al-Ghazālı̄ is an unbeliever as well. (shrink)

This dissertation offers a new and comprehensive analysis of Abū Naṣr al-Fārābī's cosmology by focusing on various important issues that have been largely neglected by the modern scholarship. It provides an examination of the physical, metaphysical, and astronomical aspects of al-Fārābī's cosmology by adopting a multidisciplinary approach that takes into account the history of philosophy and the history of astronomy. Accordingly, my dissertation explores how al-Fārābī attempted to reconcile features of Ptolemaic astronomy with Aristotelian and Neoplatonic theories, an endeavor which (...) resulted in the formulation of innovative cosmological ideas. Chapters I and II provide background information on al-Fārābī's activity as a commentator and his relation to the Greek commentatorial tradition and assess the relevant primary sources. In addition, they examine al-Fārābī's approach to cosmology and his scientific method in terms of both the Ptolemaic astronomical tradition and the Aristotelian corpus. Chapter III addresses problems related to the structure of al-Fārābī's cosmology, especially the origin of his ennadic cosmological model and his spherology. Particular attention is devoted to the question of how Aristotle's unmoved movers and Ptolemy's astronomical theories are reconciled. Chapters IV, V, and VI analyze the place of celestial matter, intellect, and motion respectively in al-Fārābī's cosmology and attempt to redefine the second teacher's relation to the various trends of Greek philosophy. The study stresses al-Fārābī's connection with the Neoplatonic and Peripatetic currents, particularly with thinkers such as Alexander of Aphrod. (shrink)