quaestio45:
Physical, metaphisical, spiritual? Or all of the above at the same time?
All of them.
So as in physical substance, correct?
Yes, in this example.
Okay then, hopefully I understand that what you mean by composition is simply to have multiple components in your being. This can be divided into the phsical, metaphysical, spiritual, and perhaps more. Now, knowledge as a collective is composed of numerous ideas, which is different from a composition of physical entities. Now, we both agree that the will in substance must be noncomposite necessarily (stemming from your argument); I’m hesitant to call this physical composition, so instead lets call it spiritual.
Now, one could make the case that the will is still composed in a metaphysical way if there isn’t a union between essence and existence (this is, of course, contingent upon the idea that the will is created, however). Furthermore, the will can hold multiple mental attributes at once (thoughts, imagination, and ideas), so it must be composed in a way different then physical or spiritual composition. Further, this composition seems similar to the composition of knowledge, which had the compenents of multiple ideas. As such, two things might be said; one, that the composition of the will is plausible outside of spiritual substance, and two, that the composition of the mind might be the same as the composition of knowledge.
That be so, we must ask the question of if it were true that composition must begat composition, then why must the composition begotten need be in any other category other than the one that the causing composition finds itself in? We must have an extra premise to explain such a phenomena if it were true.