If it is said: “We grant the soundness of Burhan Huduth Al-Ajsam, but only with respect to bodies possessing the potential for motion. But suppose there existed a body, let’s call it X, that lacked such a potential. For X then, motion is a rational impossibility, and Burhan Huduth Al-Ajsam would not apply to it.”
We respond: we can prove that any body, by virtue of its being a body, accepts motion. As such, there cannot exist a body whose motion is an intrinsic impossibility. And to prove this, we say:
This X is united with all other bodies in its being a body. And is distinguished from other bodies by virtue of its lacking the potential for motion. And what unites all other bodies with X, is other than which distinguishes them from it.
So now we investigate the modality of the relation between that which unites all other bodies with X, and that which distinguishes them from it. Either this specific difference is necessary for the essence of bodies, or it is impossible for it, or it is possible for it.
If necessary, then the potential for motion is intrinsic to the essence of bodies. So the opponent’s objection falls. For X is also a body, so in this case, X would necessarily possess the potential for motion.
If impossible, then the potential for motion would be impossible for the essence of bodies. Entailing that it be impossible for any body to move. But this is patently false, since we actually observe some bodies moving.
And if the potential for motion is only possible for the essence of bodies, then a body that lacks this potential can acquire it. And if it is possible for a body lacking the potential for motion, to acquire this potential, then it is possible for this body to move after the acquirement. Entailing that motion be a rational possibility for this body.
Thus, any body in of itself, accepts motion .
 Being a body, which is true of both X and those bodies that accept motion. For each is an instantiation of the body universal.
 What distinguishes other bodies from X, is the potential for motion that they possess, and which X lacks.
 In this case, the specific difference is the potential for motion which distinguishes the bodies possessing this potential from X.
 Such that any instantiation of this universal, must possess the potential for motion.
 Entailing, that whatever is necessary for bodies, be necessary for X.
 Such that any instantiation of this universal, must not possess the potential for motion.
 Such that any instantiation of the body universal may or may not possesses the potential for motion.
 Since in this case, the potential for motion is possible for bodies. So even the bodies that lack this potential, accept it.
 The above argument proves the essential identicality of bodies (Tamathul Al-Ajsam), and it can be used to show that whatever is possible for some bodies, is possible for any other.