prudence and mystic theology. Jurisprudence, that is to say, the canon law based on one of the orthodox systems laid down by Ab-u Hanifa and the other recognised jurists, or by their Shi'ite rivals, has always been the backbone of Islamic scholarship, and was thus parallel with the study of canon law in mediæval Europe: in each case it turned men's attention to the development of the social structure towards an ideal, and this had an educative influence of the highest value. We, holding very different principles, may be tempted to under-estimate this influence, but it is worth noting that, whilst our aims are opportunist in character, the canonist of Islam or of Christendom had a more definitely constructed ideal, with a more complete and scientific finality, which, in so far as it was an ideal, was an uplifting power. In Muslim lands the canonists were the one power which had the courage and ability to resist the caprices of an autocratic government, and to compel even the most arbitrary princes to submit to principles which, however narrow and defective they may seem to us, yet made the ruler admit that he was subordinate to a system, and defined the limits allowed by that system in conformity with ideals of equity and justice. It is interesting to note that in Ibn Sina's time mystic theology had already taken its place as a subject of serious study.
A short time afterwards a philosopher named an-Natali arrived at Bukhara and became a guest of Ibn Sina's father. Bearing in mind the technical
