Die philosophischen Abhandlungen des al-Kindi

In one place, the intellectual faculty is compared with the sensory one, and the thesis is put forward that the thought (intellectum) in the soul is nothing other than the faculty of thinking, the thinking subject (intellectus), the soul itself, just as the sensed object (sensatum) in the soul is the faculty of sensing, the sensing subject (sensus), the soul itself (pp. 5–7).

The same thought recurs in the following treatises, "de somno et uisione" on sleep and vision and the "liber introductorius".

This exposition is followed by a kind of conclusion, in which the mutual relationship of all four types of intellect is discussed (pp. 9–11).

The impression one gets from reading this and the following treatises can somewhat justify the criticism of abū'l-qāsim Ṣa‘īd ben Aḥmad al-qurtubī. He says: 1 "I cannot deny that his logical writings are gladly bought by everyone, but the benefit to be gained from them for the sciences is small, as they completely disregard the analytical method, which alone shows the way to distinguish the true from the false in all objects of investigation. Al-Kindi holds only to synthesis, from which only a limited part draws benefit due to the propositions that would have to be set forth in advance for every conviction to be won and added to our knowledge. However, the propositions to be set forth for every object of investigation are only found through analysis, and I do not know what kept Al-Kindi from applying this method, whether an underestimation of its value or some intention to withhold it from men. In any case, it is a detriment; furthermore, in the many writings of Al-Kindi on a large number of sciences, his ruinous individual views and his doctrines, which are far from the truth, show themselves, to which others add the lack of striking proofs, in place of which he lets orators and poets speak." And indeed, the writing is exclusively

1) Flügel, ibid. p. 16.