I examine the theory of conditional propositions (qaḍāyā šarṭiyya muttaṣila) and conditional syllogisms (qiyāsāt šarṭiyya) in the logical works of Alfarabi (d. 950). I contextualize Alfarabi's logical doctrines related to conditional reasoning against the backdrop of the context-theory of logic, which was developed by Aristotle's ancient commentators. I show that Alfarabi thought that conditional propositions have truth-conditions. I provide conjectural truth-conditions for conditional propositions, and conjectural validity-conditions for connective conditional syllogisms. These truth-conditions and validity-conditions are shown to be sensitive to the pragmatic conditions in which conditional propositions and arguments are deployed. I end by suggesting that Alfarabi's logical pragmatism is a consequence of his adoption of the late antique context-theory of logic rather than a result of his developing Aristotle's formal syllogistic theory adumbrated in the Prior Analytics.

This article argues that a fragment from a lost treatise by Abū Bakr al-Rāzī (d. 925) is preserved in the Book on Morphology Kitāb al-Taṣrīf) by Ps-Ǧābir ibn Ḥayyān. Paul Kraus reached the conclusion that the collection to which this book belongs was written between the end of the ninth and the beginning of the tenth century AD. This fragment represents the first attempt – to our knowledge – to analyze the logical structure of sign-based inference in Arabic, which is known as istidlāl bi-al-šāhid ʿalā al-ġāʾib among theologians and philosophers. The author distinguishes between sign-inferences based on homogeneity (al-muǧānasa), course of habit (maǧrā al-ʿāda) and traces (āṯār). After providing a translation of the fragment, the first part of this paper argues that its author is Abū Bakr al-Rāzī. My argument is based on a comparison between this text and a passage from the Doubts About Galen, which is also by Abū Bakr al-Rāzī. I hypothesize that at least two other fragments from the same work or from different works by Abū Bakr al-Rāzī are preserved in the corpus attributed to Ps-Ǧābir. The second part of the paper aims to reconstruct Abū Bakr al-Rāzī’s theory of sign-inference. In so doing, I show the historical influence that Hellenistic debates on sign-inference might have had on al-Rāzī, and I situate al-Rāzī’s theory in the context of the prominent use that the theologians of the kalām made of the istidlāl bi-al-šāhid ʿalā al-ġāʾib. To offer a more comprehensive reconstruction of al-Rāzī’s theory of sign-inference, this article compares the critical approach presented in the newly identified fragment with the epistemological framework outlined in the Doubts About Galen. Finally, this article shows that Abū Bakr al-Rāzī’s theory of sign-inference had a strong influence on al-Fārābī’s logical developments especially in his Epitome of the Prior Analytics, even if he does not acknowledge this intellectual debt.

The aim of this paper is to identify the position the ru'yat Allāh holds within the curriculum of sciences described by the Iḫwān al-Ṣafa'. Their concept of knowledge is first clarified. The Ihwan use the terminology of rational knowledge to describe items of faith too. But faith is only an introduction to a greater knowledge. Now: is the supreme knowledge to be considered as speculative and theoretical, or are the ḫawciṣṣ, the only ones entitled to the vision of God, eventually obliged to rely on a kind of divine “revelation” or “inspiration”? If the “vision of God” appears beyond any possible connotation of knowledge in “rational” terms, it is unclear, however, whether the Ihwan use the concepts of “revelation” and “inspiration” as a way of explaining in a theological terminology the utmost degree of human knowledge (perhaps according to the same analogical function waḥy and ilhām appear to have in Ibn Sīnā). Moreover, the qualities and moral dispositions attributed to the “Friends of God” remind us of Sufi doctrines. Consequently, the question of the relation between Sufism and imāmite theories could be re-opened: the Iḫwānian definition of the “science of the transcendent” shows that the gnoseological itinerary is not concluded even with the “vision of God.”

Constantine the African's significance as the first important translator of medical texts from Arabic into Latin is indisputable due to the fact that his work contributed decisively to the enlargement of medical knowledge in the Latin West. Among his considerable œuvre the translation of al-Maˇgūsī's Kitāb al-Malakī under its Latin title Pantegni, the first real medical compendium in Latin, holds a particularly important position because of its popularity. The Pantegni is divided into the two parts Theory and Practice with ten books each. Yet while the Theorica Pantegni corresponds basically to the Theory in the Kitāb al-Malakī, this is only partly the case for the Practica Pantegni. The content of the differing parts has been put together mainly from other medical texts. The identification of these other medical texts was the aim of some important researches while the last ten years (see especially the articles in Charles Burnett and Danielle Jacquart [eds.], Constantine the African and ‘Alī ibn ‘Abbās al-Maˇgūsī: The Pantegni and Related Texts [Leiden / New York / Cologne, 1994]). The aim of this article is to present the sources of the Pantegni, Practica’s third book and to give some indications on the person who made the compilation who – as it seems – wasn't Constantine the African himself.

In a departure from the tradition of the Neoplatonic commentators of the Organon, the sequence of summaries in the “Bratislava series” insert two treatises between the Prior Analytics and the Posterior Analytics, namely the Resolution (kitāb al-Taḥlīl) and the Sophistical Refutations. And even though the Taḥlīl is concerned with Book 2 of the Topics, it does not deal with dialectic. Instead, it comments on the summary of the Topics that belongs to the Prior Analytics (I, 27–30), while “completing” it. The contents of kitāb al-Taḥlīl and the different titles that the fahāris give it (e.g., fīiktisăb al-muqaddimāt), lead one to realize that it is an addition to the Prior Analytics offering a theory concerning the generation of the premisses of the syllogism, something that may have appeared to Alfarabi as missing from Kitāb al-Qiyās.

Striking similarities, often literal, between Ibn Riḍwan's Book on the Application of Logic in the Sciences and Arts and the Didascalia in Rhetoricam Aristotelis ex glosa Alpharabii lead to suppose that the first of these treatises has preserved something of the Arabic source of the second one, the Great Commentary on the Rhetoric by al-Fārābī, and to question on the originality of Ibn Riḍwan's rhetorical doctrine. In this paper, the texts on rhetoric of Ibn Riḍwan's treatise are edited, translated and placed in front of their correspondents of the Didascalia. They are then analysed and classified depending on their proximity and distance to the Didascalia. It appears that Ibn Riḍwān has, as the Didascalia, a system of the means of the persuasion which puts on the same level eight non pathetical means external to the speech, the enthymeme and the example. Nervertheless, one has also to note that Ibn Riḍwan's theory of rhetoric is radically different from Didascalia's: on the one side, a general rhetoric – non limited to specific activity, means, listeners and objects; on the other side, a special rhetoric, with such limitations. On the basis of these similarities and differences, I shall treat, in the next issue of A.S.P., the degree of dependence of Ibn Riḍwān's rhetorical doctrine towards the Didascalia, and the project underlying his work.

The modern physiological optics introduces the notions related to the conditions of fusion of binocular images by the concept of correspondence, due to Christiaan Huygens (1704), and by an experiment attributed to Christoph Scheiner (1619). The conceptualization of this experiment dates, in fact, back to Ptolemy (90-168) and Ibn al-Haytham (d. after 1040). The present paper surveys Ibn al-Haytham's knowledge about the mechanisms of binocular vision. The article subsequently explains why Ibn al-Haytham, a mathematician, but here an experimenter, did not give the circular figure of the theoretical horopter, construction due to Gerhard Vieth (1818) and Johannes Müller (1826). But, on the other hand, it is clear that Ibn al-Haytham's experimental study puts in place the notion of corresponding points, the cases of homonymous and cross diplopia, and even prepares the discovery of Panum area.

This paper sets out to chart the fortunes of one of the most significant moral propositions in Mu'tazilite moral theory — namely, that it is evil to lie, and it is evil irrespective of the consequences of so doing. The reasons which promote this principle to significance relate to the broader context of Mu'tazilite theological orientation, which aims to vindicate God's justice through demonstrating that moral value does not derive from revelation. Yet this principle suffers the difficulties which commonly afflict deontological precepts, particularly the challenges posed by their conflict with teleological moral demands in certain situations, as well as the difficulty of empirically ascertaining that a moral principle has in fact given the agent his reason for action, as the Mu'tazilites attempt to do. These were difficulties which Aš'arite critics of Mu'tazilite moral claims were quick to pick up on, and it is in the light of such hostile fire that the coherence of the Mu'tazilite position on the evilness of lies is examined. This is the principal focus of this essay, and it is complemented by an examination of how the principle carries over to the realm of divine morality: can God tell a lie? If not, why not? And what does this reveal about the ordering of moral values in Mu'tazilite thought?

Ḥunayn ibn Isḥāq's Arabic translation of Galen's commentary on the Hippocratic Epidemics is an invaluable source for our knowledge of Galenic medicine and its transmission history, not least because much of it is extant only in Arabic. Its importance for the Arabic medical tradition is amply attested in the later medical literature. It also tells us much about the methods and self-image of contemporary translators. Throughout the translation, we find remarks by Ḥunayn discussing the quality of his source text, his own interpretation and also his attempts to reconstruct problematic or damaged passages. Based on an edition of these notes, their analysis and comparison to similar texts and Galen's own thought on editing and interpreting difficult medical texts, this article aims to situate Ḥunayn's methods in the context of the Greek-Arabic translation movement. It argues that his approach differs in important respects from that of preceding Greek-Arabic and Greek-Syriac translators and that he was indebted to Galen not just as a physician, but also as a translator and exegete.

Al-Kindī's Forty Chapters was one of the most influential astrological texts in the Middle Ages in the Arabic and Latin-reading world. Yet it has never been studied by modern scholars and has not even been properly identified in the standard bibliographies and encyclopaedias of Arabic literature. This study describes the work as it appears in the Arabic MS, Jerusalem, Khālidī Library, 21(2)-Astr.-2; sets it in the tradition of Greek, Persian and Arabic texts on catarchic astrology; and traces its influence on later Arabic astrological works, which give evidence of a fuller text than that in the Khālidī Library. This fuller text appears in the two Latin translations made in the mid-twelfth century by Hugo of Santalla and Robert of Ketton. Finally some comments are added about the place of The Forty Chapters in al-Kindī's œ;uvre. Two appendixes give respectively details of the manuscripts of the Arabic text and the two Latin translations, and an edition of a specimen chapter (concerning irrigation and cultivating the land) from these three versions.

It is well-known that the Arab philosophers of the Aristotelian tradition, like some of their Alexandrian predecessors, attached rhetoric and poetics to logic, and supported this inclusion by the idea that the principal poetic procedure - that is, essentially, metaphor - is a kind of syllogism: the poetic syllogism. However, until now, no texts prior to those of Avicenna had been identified which render the structure of this syllogism explicit. In the present contribution, we present and translate a passage from al-Fārābī which shows that for him, the poetic syllogism is an incorrect syllogism of the second figure - a different interpretation from that which will be given by Avicenna.

Dans ses traités consacrés à l'âme, Ibn Sīnā élabore une doctrine complexe de la perception dont l'analyse permet de dégager deux conceptions distinctes de l'image. L'une détermine l'image comme une doublure du réel, qui re-présente quelque chose, et tient lieu d'une chose absente. Cette caractérisation de l'image comme un double et une entité matérielle qui se forme dans les puissances-organes comme par réification s'inscrit dans la conception antique et médiévale de l'image. L'image, dans l'horizon épistémique de l'Antiquité et du Moyen Âge, n'est jamais conçue, en effet, que dans sa relation à ce qu'elle représente. Le statut ontologique de cette image-reflet est celui d'un double: c'est un reflet que sa matérialité rend manifeste.

What are the proper objects of perception? Two famous responses to this question hold that they are either the images of extramental objects, that is, the way in which they appear to us (representationalism), or they are the objects themselves (direct realism). In this paper, I present an analysis of this issue by Abū l-Barakāt al-Baġdādī (d. 1164/65), a post-Avicennian scholar whose impact on the history of Islamic philosophy has been largely neglected. Abū l-Barakāt argued against the traditional Aristotelian-Avicennian epistemological dualism, which distinguishes between the sense-perception of material particulars and the conception of immaterial universals in terms of the perceiver  and/or  the  structure  of  perception.  In  Abū  l-Barakāt's  own  theory, all epistemic acts have the unified structure of direct relation between one and the same perceiver (immaterial soul) and the objects themselves – both material and immaterial. His main thesis is that having corporeal organs is not necessary for sense-perception. In the final section of the paper, I show that Abū l-Barakāt's critique of the Aristotelian-Avicennian tradition was received as a breakthrough in epistemology. It may have also determined the epistemological theories of two of the most important post-Avicennian Islamic philosophers: Faḫr al-Dīn al-Rāzī (d. 1210) and Šihāb al-Dīn al-Suhrawardī (d. 1191).

The thesis presented in the present article is not the widely-accepted one according to which Mu‘tazilite thought indirectly influenced the birth and development of Arab rhetoric (balāġa ) as an intellectual trend at the time that witnessed the constitution of this discipline of Arab language sciences, but the more specific thesis that it was primarily in Mu‘tazilite thought that the foundations of balāġa as a technical discipline were truly elaborated. To argue this thesis, we shall proceed in two stages. In the first, we shall try to identify the indirect Mu‘tazilite sources of balāġa; that is, the theses and overall positions of this movement, an echo of which may be found in constitutive elements of the discipline. In the second, we will try to identify some of the direct Mu‘tazilite sources of balāġa on the basis of Mu‘tazilite studies directly devoted to the status of the Koranic text, and the concepts elaborated to account for it.

Aristotle did not develop the quantification of the predicate, but, as shown in a recent paper by Hasnawi, Ibn Sīnā did. In fact, assuming the Aristotelian subject-predicate structure, Ibn Sīnā qualifies those propositions that carry a quantified predicate as deviating (muḥarrafa) propositions. A consequence of Ibn Sīnā’s approach is that the second quantification is absorbed by the predicate term. The clear differentiation between a quantified subject, that settles the domain of quantification, and a predicative part, that builds a proposition over this domain, corresponds structurally to the distinction, made in constructive type theory, between the type of sets and the type of propositions.

Neither did Aristotle combine his logical analysis of quantification with his ontological theory of relations or equality. But Ibn Sīnā makes use of syllogisms that require a logic of equality, and considered cases where quantification combines via equality with singular terms. Moreover these reflections provide the basis for his theory of numbers that is based on the interplay between the One and the Many. If we combine Ibn Sīnā’s metaphysical theory of equality with his work on the quantification of the predicate, a logic of equality comes out naturally. Indeed, the interaction between quantification of the predicate and equality can be applied to Ibn Sīnā’s own examples of syllogisms involving these notions. By using the formal instruments provided Martin-Löf's constructive type theory, the present paper establishes links between Ibn Sīnā’s metaphysics and his logical work: links that have been discussed in relation to other topics by Thom and Street. Ibn Sīnā did not develop a logic of identity, but he did develop the conceptual means to do so.

Scholars have long debated the possibility of a mystical or illuminationist strain of thought in Ibn Sīnā's body of writing. This debate has often focused on the meaning and contents of his partly lost work al-Mashriqiyyūn (The Easterners), also known as al-Ḥikma al-Mashriqiyya (Eastern Wisdom), mentioned by Ibn Sīnā himself as well as by numerous Western writers including Ibn Rushd and Ibn Ṭufayl. A handful of references to what is called Ibn Sīnā's “Oriental Philosophy” are also found in the Castilian and Hebrew works of the Castilian Jew Abner of Burgos (ca. 1270-ca. 1347), known after his conversion to Christianity as Alfonso of Valladolid. Although the content of these citations has not been identified, it has been proposed that they may preserve otherwise unknown passages from Ibn Sīnā's lost work. This study considers the references to Ibn Sīnā's so-called “Oriental Philosophy” within Abner's writings and concludes that rather than preserving lost passages from Ibn Sīnā's writing, Abner's references were drawn primarily from Ibn Ṭufayl and offer no support for the argument of a possible mystical or illuminationist strain in Ibn Sīnā's thinking.

John Walbridge, The Leaven of the Ancients. Suhrawardī and the Heritage of the Greeks (Albany, State University of New York Press, 2000), xviii + 305 pp.

This article explores the reception of Avicenna's theories of motion in the sixth/twelfth century. Avicenna had devised innovative ways of understanding motion in response to various challenges and conditions that the preceding philosophical tradition and his own internal critique had posed. Motion for him was either the state of being between two termini or the traversal of an interval, where the former of these was the extramentally real type and the latter a product of the imagination. In the sixth/twelfth century, the implicit critique of some leading scholars led to the adoption of the thesis in some circles that motion by traversal is extramentally real. This position was accepted as viable both by those who endorsed the atomic and the continuous theory of bodies.

This paper presents the Arabic text, the French translation and an analysis of al-Sijzīʼs treatise (second half of the tenth century), the Book of Measurement of Spheres by Spheres. In this text, al-Sijzī divides the cube into several sub-cubes and parallelopipedes, thus offering us a stereometric interpretation of algebraic identities of the third degree usually credited to mathematicians of the sixteenth and seventeenth centuries. However, this was not al-Sijzīʼs motivation for writing this treatise; rather it was his theoretical interest in the Euclidian concept of the “power” of a segment, an interest which is clearly geometric rather than algebraic. This has led al-Sijzī to the notion of dimension, at least in outline.

The classical theory of errors can be divided into stochastic and determinate parts, or branches. The birth of the first of therse became inevitable after Bradley's idea of cultivating astronomy and natural science in general by “regular series of observations and experiments” became universally accepted. Such scholars as Lambert, Simpson, Lagrange, Daniel Bernoulli and Euler were responsible for the development of the stochastic theory of errors while Laplace and Gauss completed its construction. About fifty or sixty years ago it was included into mathematical statistics.