كتاب الحيوان (Book of Animals)

In the Name of God, the Compassionate, the Merciful

We begin this part by completing the discourse on the fires of the Arabs and non-Arabs, the fires of religion, the extent of their value among the people of every creed, what among them is considered a source of pride, what is considered blameworthy, and for which its possessor is ostracized. We begin with reports about them, their origins, and their very essence. We discuss how to address their latency and emergence: whether fire existed as an entity before its manifestation; whether it exists by juxtaposition or by interpenetration; the origin of its entity if it was not latent; and the possibility of air transmuting into fire and returning to embers, provided that such transmutation is permissible and the argument for the persistence of a'rad accidents/transient properties is valid.

We further discuss the blaze that appears from wood and the sparks that appear from stone. What is the truth regarding the color of fire? Do sparks differ in their natures, or is there no difference between all their essences? Or does their variation depend on the differences in their exits and entrances, and upon the differences in what meets and excites them? We begin, with the name of God and His support, with the words of Abu Ishaq:

(Abu Ishaq said): Fire is a name for burning and radiance. When they say it burned or heated, the burning and heating occur in one of these two interpenetrating species, which is heat, not radiance. He claimed that heat is an ascending essence. They differed, and their agreement on ascending was not consistent among their essences, because when they arrive from the celestial world to a place, one becomes above the other. He would firmly assert and conclude that radiance is what ascends when it is separate, and it is not ascended upon. He said, "We only find that when we extinguish the fire of a furnace..."