Ghazālī's later attack on the essentialism of the Greek causal philosophy could also be read as a continuation of the debate against the Aristotelian essentialism that required a fixed Earth at the center of the universe, and a strict adherence to the Aristotelian cosmological universe that was not always followed by Ptolemy. In other words, those within Islamic civilization who saw in the works of Aristotle a strict essentialist philosophy could not tolerate the divergences of Ptolemy and thus initiated a whole series of attacks against his deviations. But it was those same persons with that same strict Aristotelian essentialist interpretation who were perceived by the religious camp represented by Ghazālī as going too far in their essentialism on issues of causality for example. Thus in an ironic turn of events one can say that the objections that were raised by astronomers working in the Islamic domain against Ptolemy's astronomy were motivated by Aristotelian purist astronomers who were at the same time fighting their own battle with religious people who wanted to understand Aristotle in a much more relaxed sense, almost in the same relaxed manner in which Ptolemy understood Aristotle.
Moreover, the debate that expressed itself in the Shukūk literature, of which we have seen several examples, can be perceived as one feature of a much larger phenomenon that included religious attacks against Greek astrology, observational mistakes, factual errors in medicine, etc., where such disciplines also developed under the double watchful eyes of enemies from without, who competed over the sources of authority and who had the right to claim the possession of that source, and enemies from within who competed over who was the better scientist who could qualify for the government job.
It is within this complex environment that new disciplines such as Hay a, Mīqāt and Farā'iḍ, came into being in order to satisfy the outside competition with the religiously inclined opponents, but at the same time to carve purely independent disciplines that could compete against the traditional ones, which were being promoted by fellow scientists from within so to speak. In that environment a science like hay'a became at once a religiously acceptable science, and at the same time a more rigorous science that carried the brunt of the attacks against Greek astronomy in order to prove its rigor and its good religious standing.
Within the same environment we can better understand this insistence on scientific rigor as the motivation behind the constant emphasis by hay'a authors on the inner consistency of science mentioned above, an emphasis that characterized the long history of the hay'a tradition. Hay'a authors were obviously trying to keep this double edge advantage over their fellow astronomers, such as authors of zījes for example, by remaining more stringent in their scientific consistency requirements and by remaining religiously acceptable to the society at large. In that regard they scored a tremendous success as their discipline continued to be taught till recent times, and sometimes well within the religious educational institutions themselves.
Once we can see the double motivation to attack the Greek tradition, we expect this phenomenon to have had similar effects in other fields as well. And when we consider the field of medicine for example, we arrive at very similar results. We already had a chance to refer to the text of Abū Bakr al-Rāzī in which he objected to Galen's theories but also went ahead and composed his own rigorous scientific book on the difference between smallpox and measles, a difference that was apparently unknown to Galen, despite Rāzī's protestations.
This same critical spirit was also exhibited in the work of 'Abd al-Laṭīf al-Baghdādī (d. 1231)[233] who visited Egypt toward the beginning of the thirteenth century and who also found himself on a collision course with Galen at certain medical points. In his account of his trip to Egypt, he mentioned that he had found certain anatomical points very difficult to explain to his students, and for them to understand those points, because in theory the written word was always less evident than the observation, or that "observation is always much stronger than words" as he put it.[234] This should not be surprising since dissection was not commonly practiced in premodern times. But Baghdādī went on to say that he profited from a recent plague that had befallen Egypt, and visited with his students the piles of skeletons, which were still lying on the outskirts of Cairo. During their investigation, Baghdādī related that he noted the jawbone of those skeletons, and that he found it to have been a single bone rather than two, as Galen had asserted. He went on to relate that he repeated the observation several times, in many skeletons, and that he always found it to be one bone. He then asked several other people who had also observed it in his presence and on their own and they all agreed that it was one bone. He then promised to write a treatise in which he would describe the differences between what he saw and what he read in the books of Galen. But he continued to say that he kept on investigating this issue in graveyards of various ages in order to see if a seam or a split would be observed in that bone with age. And as much as he wished to save the Galenic text, he found none.
In another instance, the same Baghdādī also reported that his original investigation was contrary to the teachings of Galen, but that later repeated observations confirmed the Galenic texts.
The works of Ibn al-Nafīs of Damascus (d. 1288), already mentioned before, fall in the same category, in that they exhibit this tendency to try to save the Greek texts from their own folly, so to speak, but having to object to them when there was better evidence of their error. Ibn al-Nafīs's discovery of the smaller pulmonary circulation of the blood comes from the same tradition as that of Rāzī and Baghdādī, and represents the empowerment that the scientists of the Islamic domain must have felt once they started noticing the exposure of a whole sequence of mistakes in the classical Greek scientific texts, and once they started believing in what they saw with their own eyes.
Other disciplines witnessed similar transformations in that they managed to cleanse the mistakes of the Greek tradition, whenever possible, but also went beyond to forge their own new terrain that the Greek authors did not know about. In particular the discipline of mathematics seems to have received a very interesting boost toward the sixteenth century when its relationship to astronomy was finally correctly understood at the hand of someone like Khafrī (d. 1550) who could finally see that mathematics was just a tool that could be used to describe physical phenomena, and that it did not retain the Truth itself.
The only astronomical criticism that was not touched upon in any detail in this overview was the criticism that was implicit in the various attempts of generations of astronomers who sought to reform Ptolemaic astronomy by constructing new mathematical models that could render the reality of observations, and the theoretical natural philosophical foundations in a much more coherent and consistent fashion. These will be explored in the chapter, which will survey the non-Ptolemaic models as was already promised.
233
The account of 'Abd al-Laṭīf al-Baghdādī is taken from his book
234
In his own words 'Abd al-Laṭīf puts it thus: "(In any case) observation (al-ḥiss literally feeling) is more valid than hearing (