The Book of That Which Has Been Established by Personal Reflection

The Book of That Which Has Been Established by Personal Reflection (Kitāb al-mu‘tabar), influenced by the eleventh-century Muslim philosopher Ibn Sīnā, addresses logic, psychology, and metaphysics. Abū ’l-Barakāt examines the philosophical teachings of earlier figures, revising their theories when necessary. The Aristotelian definition of time is that it is the measure of motion or change, and therefore is dependent on, or posterior to, motion. It is an accident, rather than a substance, and has no existence in and of itself. Here, Abū ’l-Barakāt explains his innovative theory of time, in which it exists prior to motion. Time measures both motion and rest; indeed, it measures existence itself.