The spirit, then, is a subtle body (_jismí laṭíf_), which comes and goes by the command of God. On the night of the Ascension, when the Apostle saw in Heaven Adam, Joseph, Moses, Aaron, Jesus, and Abraham, it was their spirits that he saw; and if the spirit were an accident, it would not stand by itself so as to become visible, for it would need a _locus_ in substances, and substances are gross (_kathíf_). Accordingly, it has been ascertained that the spirit is subtle and corporeal (_jasím_), and being corporeal, it is visible, but visible only to the eye of intelligence (_chashm-i dil_). And spirits may reside in the crops of birds or may be armies that move to and fro, as the Apostolic Traditions declare. Here we are at variance with the heretics, who assert that the spirit is eternal (_qadím_), and worship it, and regard it as the sole agent and governor of things, and call it the uncreated spirit of God, and aver that it passes from one body to another. No popular error has obtained such wide acceptance as this doctrine, which is held by the Christians, although they express it in terms that appear to conflict with it, and by all the Indians, Tibetans, and Chinese, and is supported by the consensus of opinion among the Shí`ites, Carmathians, and Ismá`ílís (_Báṭiniyán_), and is embraced by the two false sects abovementioned. All these sectaries base their belief on certain propositions and bring forward proofs in defence of their assertion. I ask them this question: “What do you mean by ‘eternity’ (_qidam_)? Do you mean the pre-existence of a non-eternal thing, or an eternal thing that never came into being?” If they mean the pre-existence of a non-eternal thing, then there is no difference between us in principle, for we too say that the spirit is non-eternal (_muḥdath_), and that it existed before the body, as the Apostle said: “God created the spirits two thousand years before the bodies.” Accordingly, the spirit is one sort of God’s creatures, and He joins it to another sort of His creatures, and in joining them together He produces life through His predestination. But the spirit cannot pass from body to body, because, just as a body cannot have two lives, so a spirit cannot have two bodies. If these facts were not affirmed in Apostolic Traditions by an Apostle who speaks the truth, and if the matter were considered purely from the standpoint of a reasonable intelligence, then the spirit would be life and nothing else, and it would be an attribute, not a substance. Now suppose, on the other hand, they say that the spirit is an eternal thing that never came into being. In this case, I ask: “Does it stand by itself or by something else?” If they say, “By itself,” I ask them, “Is God its world (_`álam_) or not?” If they answer that God is not its world, they affirm the existence of two eternal beings, which is contrary to reason, for the eternal is infinite, and the essence of one eternal being would limit the other.