namely, that the celestial sphere exists by necessity and is necessarily existent, admitting no nonexistence. Yet it depends upon another, and they concede that it depends upon the First, because it cannot subsist without its motion, and its motion cannot subsist without the First. Thus, it exists only through the First, so it cannot exist through itself. Rather, it is an effect of another. Whatever is an effect of another does not exist through itself; rather, that First is the cause of its existence. Wherever a cause of a thing’s existence is established, plain reason shows that the thing does not exist through itself and therefore is not necessary through itself. Whatever is not necessary through itself is contingent and originated, as has been explained at length elsewhere.

The purpose here, however, is to cite Ibn Rushd’s discussion. Ibn Rushd says:

The term “contingent” in the philosophers’ terminology does not mean what it means in the terminology of Ibn Sīnā and his followers. Whatever is beginningless and perpetually necessary through another—such that it admits no nonexistence—is not called contingent. Rather, the contingent is that which is nonexistent but admits existence. As for what has always been necessary through another, it is not contingent.

He states this in several places in his book, explaining that what Ibn Sīnā maintained departs from the approach of the ancient philosophers, and that the method by which he established