corporeal Being. If they retain this even under a change in velocity which makes it impossible for anything like 'hardness' to be, then hardness does not belong to the Being of entities of this sort. " Eademque ratione ostendi potest, et pondus, et colorem, et alias omnes eiusmodi qualitates, quae in materia corporea sentiuntur, ex ea tolli posse, ipsa integra remanente : unde sequitur, a nulla ex illis eius (sc. extensionis) naturam dependere ."ix Thus what makes up the Being of the res corporea is the extensio: that which is omnimodo divisibile, figurabile et mobile (that which can change itself by being divided, shaped, or moved in any way) , that which is capax mutationum—that which maintains  itself (remanet) through all these changes. In any corporeal Thing the real entity is what is suited for thus remaining constant [ständigen Verbleib], so much so, indeed that this is how the substantiality of such a substance gets characterized.
¶ 20. Foundations of the Ontological Definition of the 'World'
Substantiality is the idea of Being to which the ontological characterization of the res extensa harks back. "Per substantiam nihil aliud intelligere possumus, quam rem quae ita existit, ut nulla alia re indigeat ad existendum." "By substance we can understand nothing else than an entity which is in such a way that it needs no other entity in order to be."x The Being of a 'substance' is characterized by not needing anything. That whose Being is such that it has no need at all for any other entity satisfies the idea of substance in the authentic sense ; this entity is the ens perfectissimum. "... substantia quae nulla plane re indigeat, unica tantum potest intelligi, nempe Deus."xi Here 'God' is a purely ontological term, if it is to be understood as ens perfectissimum. At the same time, the 'self-evident' connotation of the concept of God is such as to permit an ontological interpretation for the characteristic of not needing anything—a constitutive item in substantiality. "Alias vero omnes (res ), non nisi ope concursus Dei existere posse percipimus."xii All entities other than God need to be "produced" in the widest sense and also to be sustained. 'Being' is to be understood within a horizon which ranges from the production of what is to be present-at· hand to something which has no need of being produced. Every entity which is not God is an ens creatum. The Being which belongs to one of these entities is 'infinitely' different from that which belongs to the other; yet we still consider creation and creator alike as entities. We are thus using "Being" in so wide a sense that its meaning embraces an 'infinite' differ· ence. So even created entities can be called "substance" with some right. Relative to God, of course, these entities need to be produced and sus· tained ; but within the realm of created entities—the 'world' in the sense of ens creatum—there are things which 'are in need of no other entity'