a self-contradictory statement whose parts cancel one another out. Such a situation can arise only where there is expansion and mutual separation, never where there is genuine union. To illustrate: when water unites with milk, or water with wine, the result of their union is a third thing that is neither pure water nor pure milk; it is a distinct third kind, and both water and milk have been altered, transformed, and intermixed. A union that involves none of these changes is simply unintelligible.

For this reason the Christians have fallen into severe confusion on the matter, their disagreements multiplying until each sect refutes the other’s claim and then advances a view that is itself refuted in turn. Thus all of their positions are invalid and rejected, for they share a corrupt premise that necessarily entails one of several consequences, every one of which is false. Whichever consequence a group adopts is therefore false, yet they cannot escape those consequences: this faction embraces one entailment and the other rejects it; the other faction adopts a different entailment and the first rejects it.

Such is the nature of every false doctrine: when a party holds to it, false entailments cling to it; and the falsity of the entailment proves the falsity of that which entails it, for whenever the entailing proposition is affirmed its consequence must also be affirmed, and when the consequence is impossible, the proposition itself is impossible.

This becomes even clearer in the fourth approach:

Many Christians say that after the union the two became one essence, one nature, and one will; this view is attributed to the Jacobites (Yaʿqūbiyya). They assert that the lahūt (divine nature) and the nāsūt (human nature) blended and fused just as water mixes with milk or water with wine. This view expresses the very reality of union; union cannot be conceived otherwise.