First some comments on the terms of the question. The medieval Aristotelians distinguished various powers of the soul, and to each power they assigned a primary object. Thus the object of the power of hearing is sound. Consider another power, the will. The primary object of the will is the good.
Ratio is a word of broad meaning.
It can be translated reason, description, nature. Whatever our intellect attains in any way, it knows sub ratione entis , in some way by reason of being. The first being is God. The question in the Scotus extract we are about to read is whether God is the being that is the primary object of the intellect. Followers of Augustine were inclined to say Yes.