except existence.

The second argument is the one on which Ibn al-Haysam relied in the debate that he claimed took place between him and Ibn Fūrak. He argued as follows:

If this judgment were explained by temporal origination, someone unaware that the heavens are temporally originated would be unaware that, in relation to all other existing things in the world, the heavens must be either spatially coincident with them or separate from them in some direction. For if a particular factor necessitates a judgment, someone ignorant of that factor must be ignorant of that judgment. Do you not see that, since existence is what calls for classification as either pre-eternal or temporally originated, believing something to be nonexistent necessarily precludes classifying it as pre-eternal or temporally originated? Likewise, since classification as black or white depends on something’s being colored, believing something to be uncolored precludes believing that it can be classified as black or white. And since we find that the eternalist who believes in the pre-eternity of the heavens