If it is objected that his point was that relational properties come into existence only when both of the related things are present—even though one of them may subsist independently of the other—then several replies may be given. One of them is as follows.

First, that is not in fact what he intended; second, even if he had intended it, it would be of no use to him; and third, it would still be an error. These are, therefore, three distinct answers.

The reason is that his discussion concerns whether the causality of the cause is produced by the cause alone, or by the cause together with the effect. Consequently, the very form of the claim must be incorporated into his proof. His own words, cited earlier, run thus: “The essence of the cause by itself does not suffice for the realization of causality, for causality is a relational property, and relational properties are not obtained by a single thing; both correlatives must be present. Therefore, if the essence of the cause does not independently necessitate the attribute of causality, knowledge of the essence of the cause can never be sufficient for knowledge of causality.” His meaning is therefore plain: the cause does not by itself necessitate the attribute of being a cause; what supposedly necessitates that attribute, according to him, is the conjunction of both cause and effect. That claim is false.

Even were one to grant that relational properties depend upon the existence of their two relata in the sense that neither of them is the cause but merely a condition—so that the relation cannot exist unless both are present—this would still not help him. For he maintains that the cause brings both together into being and that neither exists except in the company of the other. He would then be obliged to say the same about knowledge, namely that knowledge of what entails (the malzūm) necessitates knowledge both of the entailing thing and of what it entails, since in their terminology here the entailing thing is the cause and the entailed thing is the effect.

Moreover, it cannot be conceded to him that every relation depends on the simultaneous existence of both relata. Precedence, priority, and similar relational notions exist before one of the two relata comes into being. Likewise, the causality of an incomplete cause is ascribed to the cause before the effect exists; jurists call such things asbāb (legal causes). Thus they say, “Possessing the nisāb (the minimum threshold of wealth) is a cause for the obligation of zakāh,” and causality is a relational property attributed to the nisāb before zakāh actually becomes due. In the same way one may say, “This existed before that,” or “It is prior to that,” or “It precedes that.”