Left in the comment box at Disputations, and reposted here to remind me of what I said when I get fed up (again) with scholastic reasoning and St. Thomas Aquinas fans:
Even though I am very sympathetic to your viewpoint [--that much of this reasoning seems to get in the way of actual Christian conduct--I oversimplify, but that was the jist] at times even I can find the merit of St. Thomas Aquinas.
I don't find him much help for the daily encounters at the time of the encounter; however, his articulations of the truths of the faith help to inform how I react to things once I've been able to internalize them.
That is to say, that much of this theorizing and thinking is just that. But some small portion of it can trickle down and change us dramatically. I've experienced this again and again through Tom's presentation of Aquinas's thought.
That said, I find much of it to be straining at gnats. I suspect many do. Aquinas does not add to what has been revealed by Jesus Christ; however, he does provide the reasoning and the informed understanding of it.
How many angels can dance on the head of a pin? Who cares? Object, Intent, Circumstance--what does it mean? Well, I suppose it means the difference between pursuing Jean Valjean for 20 years over the theft of a loaf of bread for his starving family and Mother Teresa caring for the poor in Calcutta. The reasoning may not appeal to all--but the reasoning can inform the heart.
Nevertheless, it does, at times, seem tortuous.
And unproductive. You ask--"How can this lead to love?" And I answer, I don't really know, I don't understand it. And yet the history of the Saints and of St. Thomas Aquinas himself shows definitively that not only can it, in fact, it often does. This seems to go hand in glove with the first post of the day from the letter to the Philippians--"whatsoever is true. . . think about these things." When we start in thinking and in knowing, we can grow in loving. When we start in loving, we can learn thinking and knowing. The two comprise an ever-expanding cycle of knowledge and love IF we allow them to do so. Thus for every Thomas Aquinas there is a Thérèse of Lisieux. The two end up at the same place but arrive by different routes. Nevertheless both routes involve the cycle of knowledge and love. We cannot avoid them. True knowledge leads to love, overwhelming love leads to the desire for knowledge. Hence the need for the knowledge, not merely of St. Thomas Aquinas, but of all the Saints who have thought and loved through all of time.