Sound-minded thinkers state that whatever is merely possible cannot be anything but originated: every entity that can both exist and not exist is necessarily contingent, and—as has been set out elsewhere—must therefore have come into being.

Building on that, when they claim that the soul endures by the endurance of its object of knowledge, one observes that none of the things presently known through direct experience lasts forever without shifting from state to state. Likewise, among the intelligibles whose existence they demonstrate, nothing endures from pre-eternity to post-eternity without change except God alone. The separate intellects and souls they posit possess no reality outside the mind; they exist only in mental conception. As for the souls of the children of Adam, even if they do remain, they do so as knowing souls whose perfection and persistence depend on the continuance of what they know.

The upshot is that the soul has no object of knowledge whose everlasting permanence can be proven—save God alone—through which it might itself remain forever. And when they say that the soul becomes an intelligible world mirroring the actual world, that actual world is never fixed in a single state; it is continually moving from one condition to another.

According to the sound doctrine, the celestial spheres are created and subject to change. Even under their own assumption that the spheres are eternal and everlasting, they are not universals but determinate entities; they belong to the realm of sensibles, not that of universal intelligibles. Hence, when some of them—such as Ibn Sīnā and those like him—assert that the Lord knows particulars only in a universal manner, saying that He knows Himself and knows what proceeds from Him, they fall into contradiction: for He, exalted be He, is a determinate being, what proceeds from Him is determinate, the separate intellects are determinate, and the celestial spheres are determinate—not universal.