So, for Schopenhauer, the motive (an object of thought/"appearance") acting on a person's empirical character (his individual will) provides the sufficient reason why one conducts themselves in a certain way. Yet what does he mean here by "abstract from"??

"Only on the presupposition of my empirical character is the motive a sufficient ground of explanation of my conduct. But if I abstract from my character, and then ask why in general I will this and not that, no answer is possible, because only the appearance or phenomenon of the will is subject to the principle of sufficient reason, not the will itself, which in this respect may be called groundless"