subsisting in His essence, then it follows that things with positive existence may subsist in the Necessary Existent. This is the position of those who affirm the attributes.
On this assumption, if an infinite regress of effects and conditions is possible, this argument is invalid, and an infinite regress of acts of causation subsisting in the Eternal is possible. If it is impossible, then temporally originated things may arise from eternal causation ن, and your argument is invalid.
If causation—or what completes it—subsists in something else, then an infinite regress of conditions must be possible. If that is possible, an infinite regress of causation is also possible, and the argument is invalid.
This is because the assumption is that what completes causation subsists in something other than the causal agent. On this assumption, if an infinite regress is impossible, there would be eternal causation subsisting in something other than the essence of Allah Most High. This is false, and no one has maintained it. If its possibility is assumed, the celestial spheres could come into being through it, which is what is to be established.”
Another answer to their argument concerning causation is to say:
“If an infinite regress of effects is possible, the argument is invalid, since the celestial spheres could come into being through causation preceded by another act of causation. If it is impossible, then either temporally originated things arise from eternal causation, or causation has no positive existence. On either assumption, your position is invalid.
“This is because temporally originated things are observable and must be brought into being by an originator. This act of bringing into being is causation. If it has no positive existence, the argument is invalid. If it exists and is eternal, then temporally originated things arise from eternal causation, and the argument is invalid. If causation is itself temporally originated—on the assumption that an infinite regress is impossible—then it must have arisen through temporally originated causation, and the argument is likewise invalid.”
This is an answer from which they have no escape; it puts an end to their contentious objections.