The fourth cause which keeps people away from the study of metaphysics is their natural disposition. For it has been shown that intellectual qualities are dependent upon moral; and the former cannot be perfect unless the latter are. Now some persons are temperamentally incapable of right thinking by reason of their passionate nature; and it is foolish to attempt to teach them, for it is not medicine or geometry, and not everybody is prepared for it. This is the reason, too, why young men cannot study it, because of the passions which are still strong in them. Finally as a fifth reason, the necessities of the body and its luxuries, too, stand in the way of a person's devoting enough time and attention to this subject.[259] Like many others before him, Christians as well as Jews, Maimonides also believed that in ancient times the Jews diligently cultivated the sciences, which were gradually forgotten on account of foreign domination. Maimonides adds another reason for their disappearance, namely, that they were not disseminated abroad. They were confined to a select few and were not put down in writing but handed down by word of mouth. As a result only a few hints are found in the Talmud and Midrashim, where the kernel is small and the husk large, so that people mistake the husk for the kernel.[260] He then traces the history of philosophical thinking in Jewish mediæval literature from the time of the Geonim, and tells us that the little that is found of the Kalam concerning the Unity of God and related topics in the works of some of the Geonim and the Karaites in the East is borrowed from the Mutakallimun of the Mohammedans and constitutes a small fraction of the writings of the latter on this subject. The first attempt in this direction among the Moslems was that of the party known as the Muʿtazila, whom our people followed. Later came the party of the Ashariya with different opinions which, however, were not adopted by any of our people. This was not due, he tells us, to a deliberate decision in favor of the Muʿtazila, but solely to the historical accident of their chronological priority. On the other hand, the Spanish Jews of Andalusia adopted the views of the philosophers, _i. e._, the Aristotelians, so far as they are not in conflict with our religion. They do not follow the Mutakallimun, and hence what little of the subject is found in the works of the later writers of this class resembles our own method and views.[261]