We need not linger over al-Kindi’s logical teaching which carried on and corrected Arabic study of the Aristotelian logic. This was not a mere side issue, it is true, although logic did not play so important a part in Arabic education as it did in Syriac. In Syriac it was the basis of all that we should regard as the humanities, but in Arabic this position was taken by the study of grammar, which was developed on rather fresh and independent lines, though slightly modified by the study of logic in later times. Still, so long as the Muslim world had any claim to be regarded as fostering philosophical studies, and to a less degree even in later times, the Aristotelian logic has been only second to grammar as the basis of a humane education. Al-Kindi’s real influence is shown in the introduction of the problems of psychology and of metaphysics, and the work of the _falasifa_ centres in these two studies on the lines indicated by al-Kindi. In psychology, as we have seen, al-Kindi introduced a system already fully developed by Alexander and the neo-Platonic commentators on Aristotle, kept alive amongst the Syriac students of philosophy, and then further developed from this point by his successors. In metaphysics the circumstances were different. Al-Kindi apparently was the one who introduced the problems of metaphysics to the Muslim world, but it is obvious that he did not clearly understand Aristotle’s treatment of these problems. The problems involved in the ideas of movement, time, and place are treated by Aristotle in books iv., v. and vii. of the _Physics_, which had been translated by al-Kindi’s contemporary, Hunayn. b. Ishaq, and in the _Metaphysics_, of which at the time no Arabic translation existed, so that, so far as it was used, al-Kindi must have consulted the Greek text.