For this reason, neither of two kings can be king while the other is king; he can be king only when the other’s kingship is absent.

Furthermore, if either has power, and the only thing preventing him from having power and performing the act is the other’s having power over it and performing it, then each must be prevented at the very time he prevents the other, and possess power at the very time he lacks it. For, in that case, the other’s having power over the particular act and performing it does not prevent either from performing it. Yet that other can possess power and act only if he is not prevented, and he can be prevented only if the one preventing him possesses power. It follows that this one possesses power only if he lacks power, is prevented only if he is not prevented, and acts only if he does not act. This combines two contradictories.

All this is evident to people’s innate understanding. They know that if someone is a commander, is entrusted with carrying out an act, leads a group, or occupies a place, another cannot be commander, be entrusted with that act, lead that group, or act while the first is commander, holds that responsibility, leads that group, or occupies that place.

It is thus clear that one who has the power to perform an act cannot perform it while another is performing it, nor while another has power over it.

As for his having power while another is performing the act, its impossibility is obvious.

As for his having power while another has power over it, he cannot perform it unless the other refrains from performing it and leaves him to act alone. While the other is performing it, however, he has no power to do so.

It is thus clear that the coexistence of two beings, each possessing power independently, is intrinsically impossible, as all people’s innate understanding recognizes.