He also said—may Allah sanctify his soul:
(*)
Section
It may then be said: This also entails that neither of them is necessarily existent in itself, self-sufficient, and self-subsisting. Rather, each depends on another in its essence and attributes, just as it depends on that other in what it brings about. For if each depends on the other in what it brings about and is incapable of doing so alone—as joint agency necessarily entails, as explained above—(*) then either it can possess the power to act independently, such that this is possible for it, or this is not possible.
The latter is impossible. For if it were impossible for a thing to be within the power of one agent and possible for that agent to bring about, it would also be impossible for it to be within the power of two agents and possible for them to bring about. Whether a thing is possible and within an agent’s power does not vary according to whether the agents capable of bringing it about are one or many. Thus, if it is impossible for a thing to be brought about through the power of one agent, it is impossible for it to be brought about through the power of two. Conversely, if a thing is possible and can be brought about through the power of two agents, it can also be brought about through the power of one.
This is clear if possibility and impossibility arise from a characteristic of the possible thing—the thing brought about and subject to power—for its intrinsic attributes do not differ between the two cases. The same applies if they arise from a characteristic of the agent possessing the power. For the power that subsists in two is not precluded from subsisting