 By the early tenth century, the whole of Aristotle’s Organon was available in Arabic. It was an extended Organon, which included the Rhetoric and the Poetics. Logic was seen as providing the rules for different sorts of discourse, of varying levels of intellectual value. At the bottom were poetic syllogisms, then rhetoric, then the dialectical syllogisms of the Topics and finally, as the peculiar preserve of philosophers, demonstration, the theory set out in the Prior Analytics and applied to knowledge in the Posterior Analytics and, so it was thought, according to which Aristotle constructed his entire system of thought. Avicenna did not reject this overall view, but he was mainly interested in refashioning Aristotle’s (demonstrative) syllogistic, even more thoroughly than he reshaped his metaphysics and natural science. He combined categorical and hypothetical syllogistic into a single theory, and he vastly complicated Aristotle’s system by introducing temporal qualifications into every sort of syllogism (see entry on  Ibn Sina’s logic).  Except in Islamic Spain, Avicenna’s logic replaced Aristotle’s.