It becomes evident that there could be only one being of such a nature, because the kind of necessity that belongs to a being that owes its existence to no outside cause cannot be shared. Because there cannot be multiple beings all of whom derive the necessity of their existence from themselves, the unique perfection of such a single and preeminent nature is ensured. Duns Scotus turns from the internal consideration of such a first principle to argue that, moreover, there is nothing about the multiple entities in the world that requires more than a single first principle for their explanation. Because multiple first principles are not necessary, it would be foolish to posit more than the single first cause that the explanation requires.
A multitude cannot be from itself; a first cause is required to explain such existence. A unitary and unique being requires no previous cause; it can explain multiple beings without itself requiring explanation. Explanation ends when simplicity is reached. In the essential orders, an ascent is made toward unity and fewness, ending in one cause. Such a first efficient cause contains every possible actuality. No possible entities can be conceived of as being outside its nature. Thus it is perfect.
Nothing shares perfectly unless it shares, not of necessity, but from the liberality of its nature. Such a consideration of what perfection means leads Duns Scotus on to consider the divine will. If such a first principle must share its being with other beings, due to its natural liberality, then “will” must have an important place in such a nature as essential to its perfection. Along with this necessary endowment of will, Duns Scotus describes his God as being simple, infinite, and wise. Such essential simplicity excludes all possible composition in the divine nature. It is not a being made up of parts as other beings are. None of its perfections are really distinct from the others, although our language and the process of analysis force us to consider each perfection as if it were in some way separate and distinct.