[26:1] Dr. Boer, in his Philosophy of Islām, gives a full account of the Philosophy of Al-Fārābī and Avicenna; but his account of Ibn Maskawaih's Philosophy is restricted to the Ethical teaching of that Philosopher. I have given here his metaphysical views which are decidedly more systematic than those of Al-Fārābī. Instead of repeating Avicenna's Neo-Platonism I have briefly stated what I believe to be his original contribution to the thought of his country. [26:2] Saraḵẖsī died in 899 A.D. He was a disciple of the Arabian Philosopher Al-Kindī. His works, unfortunately, have not reached us. 1. _The existence of the ultimate principle._ Here Ibn Maskawaih follows Aristotle, and reproduces his argument based on the fact of physical motion. All bodies have the inseparable property of motion which covers all forms of change, and does not proceed from the nature of bodies themselves. Motion, therefore, demands an external source or prime mover. The supposition that motion may constitute the very essence of bodies, is contradicted by experience. Man, for instance, has the power of free movement; but, on the supposition, different parts of his body must continue to move even after they are severed from one another. The series of moving causes, therefore, must stop at a cause which, itself immovable, moves everything else. The immobility of the Primal cause is essential; for the supposition of motion in the Primal cause would necessitate infinite regress, which is absurd. The immovable mover is one. A multiplicity of original movers must imply something common in their nature, so that they might be brought under the same category. It must also imply some point of difference in order to distinguish them from each other. But this partial identity and difference necessitate composition in their respective essences; and composition, being a form of motion, cannot, as we have shown, exist in the first cause of motion. The prime mover again is eternal and immaterial. Since transition from non-existence to existence is a form of motion; and since matter is always subject to some kind of motion, it follows that a thing which is not eternal, or is, in any way, associated with matter, must be in motion. 2. _The Knowledge of the Ultimate._