In reply: Were an infinite regress in effects admissible, this proof would collapse, for it is erected upon the impossibility of such a regress. It is objected, however, that the proof actually rests on the impossibility of an infinite regress in the very root and genus of causation; what is held to be possible is only a regress in the genus of effects and in individual acts of causation, not in the genus of causation itself. The distinction between regress in effects and regress in causation has already been established, and the impossibility pertains to regress in causation—that is, in its genus. This, then, is the objection directed against that answer.

The reply to this objection is as follows: If a regress in effects and in particular acts of causation is possible, then these celestial spheres may well be contingent—created by something that existed before them—just as the Messengers have informed us. They reported that God created the heavens, the earth, and all that lies between them in six days, while His Throne was upon the water. They also reported that:
“Then He turned toward the heaven while it was smoke and said to it and to the earth, ‘Come, willingly or unwillingly.’ They said, ‘We come willingly.’” (Fussilat, 11)

The “smoke,” according to the exegetes, is vapor—the vapor that rose from that water. Thus they conveyed that the heavens were fashioned from a pre-existent matter, and that matter itself could have been fashioned from yet another matter, just as God created man from matter and created that matter from another matter.

If this is so, the very regress they allow with respect to effects invalidates their argument for the eternity of the cosmos, and that is precisely what is desired. They argued for its eternity only on the ground that the fully sufficient cause must be established from pre-eternity, for if it were not an agent and then became one