Potestas Essendi

A Virtual Space for Thoughts on the Middle Ages, by Nicola Polloni


Dissemination and scientific popularisation play a pivotal role in academia: research and research products need to be spread outside the ‘Ivory Tower’ in order to contribute to the social discussion and elaboration of philosophical, historical, and scientific themes, some of which – such as the cross-cultural exchange of knowledge among Christians, Jews, and Muslims – are of the utmost importance in our days. 

Traducción y circulación del conocimiento árabe a finales del siglo XII: unas notas introductorias

Los mil años que separan la caída de Roma y las noventa y nueve tesis de Lutero están marcados por un incesante movimiento de personas, confines, ideas, mercancías, problemas y libros. Mediante estos movimientos, conocimientos y practicas circularon más allá de toda frontera geográfica, teológica y cultural, remodelando y refundando enteras tradiciones que estaban atadas entre sí por numerosos factores y un mar común. En sus orillas, se hablaban cuatro lenguas principales: árabe, hebreo, latín, y griego. Los movimientos de traducción que tuvieron lugar en todo el Mediterráneo durante la Edad Media y el Renacimiento estaban finalizados en superar estos límites lingüísticos y hacer disponible nuevo y precioso conocimiento. Se trata de una larga historia, cuyas raíces departen del comienzo mismo de la civilización humana.

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KATJA KRAUSE & NICOLA POLLONI (Durham University): ‘The Light of Nature? No “Experience” in the Middle Ages!’

THERESE CORY (Notre Dame University): ‘Aquinas on Experience and Its Scope’

In this paper, I examine Aquinas’s use of the term experiri and related terms (sentire, videre) in reference to a certain kind of “experiential presence” of an object to an intellect.  Under what conditions, exactly, does this experiential kind of presence occur, and why does Aquinas accord it a special status?  I argue that for Aquinas, experiential presence has to do with a certain kind of causal relationship and likeness, which affects the way in which we are able to be assimilated to (and hence conceptualize) an object.  While sensation is a paradigm case of experiential presence, he holds that experiential presence is also possible on the intellectual level, not only with respect to material objects, but also immaterial objects.

DAVID CORY (Notre Dame University): ‘The “obscure and hidden” work of the vegetal soul in Thomas Aquinas’

In commenting on II De anima, Aquinas remarks that the work of the vegetal soul is obscure and hidden: “[Aristotle] shows that the works of the vegetative power are from the soul, which was necessary because since the active or passive qualities contribute to their operations, it may seem to someone that they are from nature and not from the soul.  And it is especially so because in plants life is obscure and hidden (Sentencia De anima, lib. 2 l. 7).” The obscurity of the soul comes from its use of the active and passive elemental powers, which are the ordinary active principles by which change occurs in the natural world. In other texts, e.g. Q. disp. de anima 13, Aquinas makes a different distinction between two classes of nature, inanimate and animate. There he says that the vegetal soul transcends inanimate nature (but not nature absolute) in its manner of acting. I contend that Aquinas is using the elemental active and passive powers to set an upper boundary on the kind of operation which vegetal souls can produce. This delimitation of the power of the vegetal soul does not reduce its work to that of the active and passive elemental powers. It does, however, make the distinction between inanimate forms and vegetal souls obscure and hidden. The implication of this “hidden” work for natural philosophy is that it is possible to give a relatively complete account of the life of plants at the level of instrumental causes, by considering only the kinds of causes familiar to the student of inanimate operations. While a truly complete account would, of course, consider those instrumental causes relative to their principal cause, the “obscure and hidden” character of the vegetal soul explains why it is easy to mistake the relatively complete account for the truly complete one.

CELIA LOPEZ (Universidade do Porto): ‘Experience and Self-Knowledge in Petrus Hispanus’s Theory of the Soul’

Among the philosophical questions concerning human cognition, the problem of self-knowledge seems to deserve a special inquiry due to its special condition as the object as well as the subject of knowledge itself. In the Middle Ages, this philosophical discussion could be boiled down into two main epistemological approaches, with roots in antiquity: the Platonic one, which considers that some kind of self-knowledge exists in the soul from its beginning, and the Aristotelian one, which conceives it as a secondary and a posteriori knowledge. Thus, many texts on psychology of the first half of the 13th century are good examples of the attempt of reconciling elements of both theoretical positions. This happens with the Sententia cum questionibus in libros De anima I-II Aristotelis, attributed to Petrus Hispanus, where the Aristotelian understanding of the soul is not to replace completely the Neoplatonic frame provided early in the Sententia. In consequence, some kind of self-knowledge is guaranteed from the very beginning of the soul, before the acquisition of species, as Boethius and Augustine defended. The aim of this paper is to describe self-knowledge according to Petrus Hispanus as well as making some remarks on it against the background of his eclectic psychological and epistemological theory.

JON MCGINNIS (University of Missouri – St Louis): ‘A Matter of Priorities: Avicenna’s Solution to Meno’s Paradox and Its implications for the Sciences’

NICHOLAS OSCHMAN (Marquette University): ‘Translating Truth into Images in al-Fārābī’s Polis’

In al-Madīna al-Fāḍila and elsewhere, al-Fārābī envisions a healthy polis as a city ruled by a wise man who is simultaneously a philosopher, a visionary prophet, and the owner of a perfected representative faculty. This Imām, understanding that many citizens are themselves unable to encounter truth directly through science and demonstration, is charged, nonetheless, with communicating truth to his citizenry. Thus, this Imām must somehow translate philosophical truths to those who cannot themselves assess the validity of demonstrations, via his perfected intellect and representative faculty, in order to rouse citizens’ imaginations by well-chosen words. In this function, the Imām must be a philosopher qua poet, who establishes laws, myths, and images which are, strictly speaking, not true, but are nonetheless similitudes of the truth. He must translate demonstrable truths into the imagery of religion, and when the Imām does so, al-Fārābī insists that the former can be known through the latter. Unfortunately, al-Fārābī never clearly explicates how demonstrable truths, i.e. propositional truths, can be translated faithfully into the symbols and laws of religious imagery. In this paper, I aim to elucidate why al-Fārābī believes that philosophical truths can be known through the particularity of religious images and the mechanisms by which the translation of philosophy into images occurs. In doing so, I hope to articulate the Fārābīan limitations of translating philosophical knowledge into imagistic expressions.

FEDERICO DAL BO (Universidad Autónoma de Barcelona): ‘The “Sacrifice of Isaac” as God’s Self-Testing in the XIII Century Spanish Kabbalah’ 

The “Sacrifice of Isaac”—known as the “Binding of Isaac” in Jewish exegesis—is traditionally interpreted by Jewish commentators as Abraham’s final test: after being chosen as God’s champion and having become the first Jew on earth, Abraham is tested once more time and asked to sacrifice his own son Isaac as a human sacrifice to God. Jewish Kabbalists—especially the 13th century Spanish mystics Rabbi Yosef ben Abraham Gikatilla and Moshe de Leon—diverged from Jewish classical exegesis. At first, they acknowledged the classical assumption that God is testing Abraham, according to the letter of Scripture and yet argued that its mystical meaning would be much deeper—God would actually be testing Himself and proving the metaphysical necessity of balancing the different nuances of His divine “personality,” by teaching Himself both “fear” and “mercy.” In my paper I will address the kabbalistic interpretation of the “Sacrifice of Isaac” and show its human-divine ambivalence, due to a number of metaphysical presuppositions—especially the assumption that God and man are interconnected in terms of macro- and microcosm. With respect of this, Abraham’s human experience is translated into God’s divine experience and transformed into a metaphysical event that brings balance in God Himself.

STEVEN HARVEY (Bar-Ilan University): ‘The Place of Observation and Experience in the Quest for True Knowledge among Jewish Aristotelians in the Thirteenth and Fourteenth Centuries’

Jewish Aristotelians of the thirteenth and fourteenth centuries, following their two philosophical authorities, Maimonides and Averroes, sought truth and human perfection through the orderly study of Aristotle’s books on logic, natural science and metaphysics, as they were paraphrased and explained by Averroes. Averroes had famously claimed that Aristotle had originated these three disciplines and completed them. He thus saw his task as the study and explication of Aristotle’s writings. Jewish thinkers in turn expressed their intentions to convey, explain, simplify, and even – on occasion – critique Averroes’ commentaries on Aristotle. But did these thinkers really do as they wrote? And, in any case, was the careful study of such authoritative texts, combined with competence in formal logic, sufficient for leading one to true knowledge and perfection? In this paper, I will consider the role of observation, oral reports, and experience for late medieval Jewish thinkers in the study of physics, astronomy, meteorology, medicine, dreams and prophecy. For example, to what extent did experience (tajriba) for Maimonides have epistemological relevance outside of medicine? How did thirteenth-century Hebrew encyclopedists use experience to counter Averroes’ argument that theoretical knowledge cannot be acquired in dreams? Did the growing skepticism of medieval Jewry’s leading scientist, Gersonides, really lead him to abandon the search for truth in natural science, and instead devote virtually all his energies to observation and mathematical calculation in his attempt to solve problems associated with astronomy? Did the same Gersonides maintain that experience (nissayon) testifies to the fact that the future can be foretold in dreams and in prophecy? How did Ḥasdai Crescas, in his revolutionary critique of Aristotelian physics, use observation to reject some of Aristotle’s fundamental scientific teachings? And what led Joseph Albo in the early 1400s to emphasize the value of experience (nissayon) for natural science as well as for establishing theoretically the immortality of the soul from the Torah?

JOSÉ HIGUERA RUBIO (Universidade do Porto): ‘Ars experimentalis: Experience in Demonstrative and Productive Disciplines’

In Metaphysics (981a15-982a8) Aristotle deals with the relation among three aspects of prime philosophy: «art» as a productive or operative discipline; «science» as demonstrative knowledge of nature, and the concept of «experience». In this relation experience is a common source of art and science, since the repeated operation on the same matter produces the «expertise» on the operative arts. This fact happens in a similar way on science, because the inductive collection of sense data -the accumulative memories of particular experiences- has as an epistemic consequence: the inference of general truths. Furthermore, the sum of expertise in arts and general truths on sciences represents a sign of wisdom. In the Arab tradition, Avicenna criticises the assumption that accumulative experiences (tajriba) can produce science, while Maimonides finds that the use of medicines in similar conditions cannot guaranty good results. The 13th century masters -e. g. Aquinas, Albertus Magnus or Roger Bacon- try to build a consistent model of experience, in which art and science are differentiated by the peculiarities of each one. On the one hand, art faces unpredictable conditions that are operating on the matter; on the other hand, science holds its own principles that are knowable without experience. Both require experience: art for improving abilities and science for collecting demonstrative data. The flexible functions of experience on the art-science relation has an important role in disciplines such as practical geometry, astronomy, and dialectics. These examples demonstrate that operational expertise combined with the knowledge of principles, of geometry and logics, achieves a multidisciplinary model that, although it does not mean precisely an «experimental method», would represent a medieval model of ars experimentalis.

MÁRIO CORREIA (Universidade do Porto): ‘Experience and Natural Philosophy in Italian Renaissance Scholasticism: Gomes of Lisbon’s Scotistic Response to Nicoletto Vernia’

During the 15th and the 16th centuries, one of the most controversial philosophical disputes was the question of method in natural philosophy. The tension between observational experience and geometrization, demonstration from the effects (demonstratio quia) and from the causes (demonstratio propter quid), and also between Aristotle’s authority and new philosophical tendencies made some philosophers search for new solutions. Others criticized this new solutions and tried to show the validity of several medieval scholastic readings of Aristotle. With this communication, I intend to present the role of experience in the dispute between Nicoletto Vernia’s Averroistic approach to the subject-matter of natural philosophy and Gomes of Lisbon’s Scotistic response to it. While Vernia considers that the subject-matter of physics is mobile body, Gomes argues it is natural substance. What is at stake is how to combine experience, definition and demonstration in the process of knowledge.

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The Toledan Translation Movement

This lecture is centred on the rise and development of the Arabic-into-Latin translation movement in Toledo in the second half of the twelfth century. A short presentation of the cultural landscape of the twelfth-century philosophical debate offers the context on which and from which the first translations were realised with the aim of providing new scientific and philosophical texts to the Latin scholars. Mirroring the rising Greek-into-Arabic translations that were taking place between Southern Italy and the Byzantine territories, a first generation of translators spread throughout the Iberian Peninsula (and beyond), making available to the Latin audience a wide number of scientific writings. A fact directly related to the developments of the political situation after the taking of Toledo (1085) and the Almoravid dominion in Al-Andalus. The passage to the second generation of Arabic-into-Latin translators is marked, too, by the socio-political situation of the Iberian Peninsula. In the second half of the century, the main centre of the translating activity is Toledo, and the lecture considers the different factors that made possible the establishment of the translation movement in that town. Finally, the biographies and contributions of the three most important Toledan translators – Gerard of Cremona, Dominicus Gundissalinus, and Michael Scot – are briefly presented and discussed, pointing out the pivotal role they played in the ‘philosophical revolution’ that was going to take place in Latin Europe thanks to the ‘new’ works translated into Latin.

Dominicus Gundissalinus: Metaphysics and Cosmology

This lecture examines the metaphysical and cosmological reflection by Dominicus Gundissalinus (1125ca.-1190ca.), translator from Arabic into Latin and original philosopher active in Toledo in the second half of the twelfth century. After a short exposition of the contents and theoretical developments of Gundissalinus’s two cosmological writings – De unitate et uno and De processione mundi – the focus is centred on the peculiarities of Gundissalinus’s interpretation of the Arabic sources he used, and particularly Avicenna and Ibn Gabirol, and Gundissalinus’s attempt at assimilating their metaphysical doctrines into the Latin philosophical tradition. Particular attention is also paid to the progressive problematization of Ibn Gabirol’s ontology (namely, universal hylomorphism) by Gundissalinus. This problematization is accompanied and led by Gundissalinus’s progressive acceptance of the ontology proposed by Avicenna in Liber de philosophia prima, I, marking a theoretical shift between De unitate et uno and De processione mundi, the latter being possibly Gundissalinus’s last treatise to be written.

Gundissalinus’s Psychological Reflection

Following the examination of the main metaphysical problems with which Gundissalinus dealt in his cosmological works (see AAIWG/RS-2), the third lecture of the research seminar is dedicated to the analysis of Gundissalinus’s discussion of psychology. The lecture exposes the main features presented by Gundissalinus in his De anima, and the peculiarities on the use of his Arabic and Latin sources, regarding the four main themes discussed in Gundissalinus’s writing: the existence of the soul, its ontological composition, its origin and immortality, and the psychological faculties.

Attempting an ‘Epistemological Revolution’: Gundissalinus’s De divisione philosophiae

This lecture examines the epistemological reflection by Dominicus Gundissalinus exposed in his De divisione philosophiae. After a brief analysis of the problems arising from the consideration of Gundissalinus’s De scientiis as an original work, the focus of this lecture is centred on the examination of Gundissalinus’s perspective in his treatise On the Divisions of Philosophy, paying particular attention to his prologue, where the Toledan philosopher presents his articulation of knowledge, and to the so-called Summa Avicennae de convenientia et differentia scientiarum praedictarum, a section in which Gundissalinus expounds the principles through which the division he proposes is pursued. The final part of the lecture is then focused on the analysis of two exemplar cases of sciences and disciplines presented by the De divisione philosophiae: natural philosophy and metaphysics.

Theoretical Enthusiasm and Doctrinal Condemnation: 1181-1215

The previous lectures have examined one of the first and most exemplar cases of Latin assimilation of Arabic philosophy, i.e., Dominicus Gundissalinus’s reflection. The final lecture of the research seminar is centred on the decades between the end of the twelfth and the beginning of the thirteenth century, examining how the Arabic writings translated in Toledo were received, criticised, and assimilated by the Latin thinkers. The first writings to be analysed are the two anonymous treatises De causis primis et secundis and De peregrinationibus animae apud inferos (or ‘Anonymous D’Alverny’), together with Daniel of Morley’s Philosophia. In these works one can clearly see two different ‘patterns’ for the reception of the Arabic writings, different perspectives that share some interesting theoretical points. A rather different approach characterises the following generation of thinkers dealing with these texts. The lecture takes into account some exemplar cases of this attitudes (Alexander Neckam, John Blund, Robert Grosseteste). Finally, the focus is centred on Paris, and the condemnation of Aristotle’s natural philosophy and its commentators in 1210/15.

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Gundissalinus, Avicenna, and the Road to Paris

Lecture given at Marquette University, Milwaukee (WI), in November 2016. Together with two further, anonymous works,  the De causis primis et secundis and the Book on the Peregrinations of the Soul in the Afterlife, Gundissalinus’s writings mark the theoretical and even material path that will lead to the great receptions and criticisms of Avicenna and the other ‘Arabs’ in Paris and Oxford during the thirteenth century and beyond—from John Blund to Albert of Cologne, Thomas Aquinas, Roger Bacon, and Duns Scotus. I will try to cast some light on this very first stage of ‘theoretical appropriation’ of Avicenna’s doctrines in the Latin West, analysing how Avicenna’s doctrines have been accepted or rejected by Gundissalinus and the two anonymous authors of the De causis primis et secundis and the Book on the Peregrinations of the Soul in the Afterlife, and pointing out, in particular, the role played by other translations produced in Toledo on Avicenna’s philosophical reception.

Link to the video

Filosofia Medieval:
em curso e em toda a extensão 

Apresentação de livros – Porto, 12 de janeiro de 2017