Thank you for your reply. But, I still don’t understand Aquinas’ proof. You say that ““A thing is desirable only in so far as it is perfect” = the “perfect part” of a thing is what makes it desirable”. So, it seems that you are saying that “perfect” = “desirable”. Is it right? If it is, then, how to understand that “everything is perfect so far as it is actual”, as said in Aquinas’ proof. Can there be a being that is actual but not perfect (that is, not desirable)?
Aquinas’ proof means that a being is desirable as long as it exists. But I cannot understand why a being is desirable as long as it exists. Can you help me?
Perfect means fully what its form defines. The form of an apple does not include the defect of a bruise, resulting in soft tissue under the bruised and discolored skin there on the apple.
It is a “perfect apple attended by accidental defects that are not part of its perfection”.
I do not throw out the apple for an attending defect, but I also do not desire or delight in the bruise on the apple - that I throw away into the garbage. So I desired the apple, but only in so far as it was perfect. There was also a green, unripe apple on the table. I did not take it (save that for later; I will one day desire it). It is not a perfected apple, but is in potential to perfection, potential to completeness of being ripe.
But the actual thing desired, again, is not the apple, not any apple.
The actual thing desired is the visualized image, that the will is moving my body to materialize.
The thing desired is my own perfection of appetite, where I imagine the goodness of eating a luscious apple. There is no bruise on the apple I imagine, so I have to “fix the apple”, I have to make it fully like my imagination of it - that imagination is the perfect object. That imagination’s fulfillment is what I am desiring to make real with the actual apple.
I am a being, I am actual, but I have defects attending to me also. And I am “not ripe”, too. I have not manifested yet my full form as “son of God” so that I shine like the Son.
Perfect means the object and form agree: the form does not define defect (only deviation from the form is defect); the form manifested in matter happens over time, so that in the intervening time there is not Yet perfection, but movement toward complete matching.
Desirable and good and true are all convertible. Perfect, however, is when that which is desirable reaches the last stage of desire (or last stage of love), which is the obtaining and enjoyment of the desired reality (when I am chewing the apple).
There is a sense in which the imagination of eating the apple is “perfect” in anticipation, perfect in potential (like the form of a body is perfect, but not yet manifested in Act).
When we desire God, it is not “Perfect God” we are desiring, but the “perfection of ourselves being in the Perfect God’s presence, knowing each other.” Union is perfection, union and enjoyment of that union.