Al-Kindi and Medieval Islamic Astrology: Causality, Free Will and the Transmission to Europe

from cause and effect. Indeed he continues: [...] the opinion of the contingency of things has developed in the minds of most people, who, seeing that an event occurs differently under similar circumstances depending on the moment, judge it contingent, so that before it happens they consider it possible that it may or may not occur. Al-Kindi thus reaffirms the law of causality: what is inferior, like the world of elements, is dominated by what is superior to it, like the world of celestial harmonies, but the role of the human spirit in its hierarchical relationships with celestial harmonies is not treated in the passage in question. For al-Kindi, in fact, human will and desire can insert themselves into the fabric of causal relationships dictated by the stars and modify them by supporting them or hindering them. In the rest of the treatise, al-Kindi pursues precisely this path, suggesting favorable timing choices, appropriate prayers and representations that can help the undertaken operation. In particular, for al-Kindi, the stars are not the only source of celestial radiation, but all natural realities such as metals, gems, drawings or the human voice are sources of such radiation. This being the case, man, through will and precise operations, can create an appropriate astral current capable of supporting or hindering the action promised by the planet: "Now it is good to know that the star and the sign dominating in celestial harmony at the beginning of any voluntary operation preside over that operation until its end. Therefore, if they are propitious, they protect that action from obstacles. If instead they are hostile, they oppose it. And since every star and every sign has its own names and characters conforming to itself in power and effect, as has already been said, at the beginning of any voluntary work it is necessary that the names be pronounced. If they are concordant with the star or sign, they naturally lead the action to a good end, but if they disagree, they spoil it. And, similarly, the formation of emblems at the beginning of any voluntary work is useful to free it from obstacles or to oppose, depending on whether they agree or disagree with the dominating stars and signs.[...] Therefore it is clear that prayers, conjurations and invocations performed through sounds significant in men's opinion, with will and desire, at the beginning of any voluntary work, help in directing this action." Al-Kindi's fatalism is therefore only apparent: planetary astral currents are not the only currents contemplated by al-Kindi, and astral radiations can actually be produced, supported and opposed by human will and certain measures he lists in his treatise. Al-Kindi's position seems anything but fatalistic. The causality of the de Radiis is reciprocal: the stars influence man and man influences the stars. From this double and reciprocal influence derives the celestial harmony from which everything happens by necessity. A completely different discourse seems to be that relating to al-Kindi's disciple, Abu Ma'shar, who appears notably more fatalistic, at least in the European translations that have come down to us: "When the planets through their motions will have indicated that a thing will not be, it will be impossible for it to be. And when the planets through their motions will have indicated in the same way and equally the effect of a thing, at the hour of indication, that effect will necessarily occur. [...] And just as the planets indicate the possible and the choice, which is proper to man, so they indicate that man does not choose except what the planets have signified." Abu Ma'shar's position nevertheless reflects an approach widespread among Arab astrologers and which, to be countered, will require the action of a very great theologian such as Saint Albert the Great, capable of resolving once and for all the antinomy between astral predestination and free will. From the 10th century onwards, Arab knowledge began to spread, albeit timidly, in Europe; evidence of this is the request of Gerbert of Aurillac, the future Pope Sylvester II, to Lupito of Barcelona to send him the astrological treatise translated by him. If therefore the translation movement has some anticipators already from the 10th century, it is nevertheless only at the beginning of the 12th century that the first copies of astronomical tables and some Arab astrological writings begin to circulate, first of all Abu Ma'shar's Introduction to Astrology translated by Adelard of Bath. What has been called the Renaissance of the 12th century rests on great translators such as Gerard of Cremona, who translated more than 87 treatises from Arabic to Latin, John of Seville, passionate and cultured in astrology who will translate a large number of texts, Plato of Tivoli translator of Messahalla and Ptolemy's Quadripartitum, and the two Robert of Chester and Herman of Dalmatia induced by Peter the Venerable to translate the Quran, al-Kindi, al-Khwarizmi's Algebra as well as some alchemical writings such as the testament of Morienus Romanus which will be treated subsequently. Thanks to the action of all these translators, the Arab astrological works of Messahalla, Abu Ma'shar, al-Kindi, al-Battani, Thabit ibn Qurra, al-Qabisi, etc. spread throughout Europe giving a strong impulse to astronomy, astrology, medicine, philosophy, alchemy and generally to all the sciences mastered by the Arabs. The diffusion of Arab writings in Christian Europe inevitably placed the intellectuals of the time before a dilemma of not easy resolution. Almost all the astronomical-astrological science of the time was in fact mediated by Arab scholars, that is, it came from the mediation of exponents of another religious confession, thus naturally posing the problem of how much of the astrological writings was Christianly acceptable and how much execrable. Therefore, on one hand the Christian intellectual world felt the need to access that scientific advancement brought by Arab writings, on the other it appeared naturally disoriented before a culture and religion it knew scarcely. Given the contingent situation, the need for an interpretative guide soon appeared evident that would allow, at least in the astronomical field, where the gap between Christian science and Islamic science was most evident, to discriminate admissible writings from those contrary to genuine Christian doctrine. With this idea...