Thus, if it is said that the essential attributes are those internal to the quiddity and those external to it—meaning by “internal” what the expression signifies by inclusion, and by “external” what it signifies by implication (1)—then this is correct.

Whether something is internal or external in this sense depends on what the speaker conceptualizes. If someone conceptualizes a rational animal and says, “human being,” the expression signifies the composite whole by correspondence, either component by inclusion, and a necessary concomitant—such as being capable of laughter—by implication. If he conceptualizes a human being capable of laughter, the expression “human being” signifies the composite whole by correspondence, either component by inclusion, and a necessary concomitant—such as its being (2) rational—by implication.

As for the claim that, among the attributes necessarily belonging to the subject as it exists externally, some are internal to its reality and quiddity, [while others are external to its reality and quiddity] (3); that the internal attributes are essential; and that the external attributes are divided into those necessarily concomitant with quiddity (4) and existence, and those necessarily concomitant with existence but not quiddity—all of this has been discussed at length [in various places] (5). We have explained the fallacies contained in Greek logic, some of which originated with their First Teacher and others from alterations made by later thinkers.

We have also discussed [one by one] (6) what their leading authorities stated on this matter, such as Ibn Sīnā