The Metaphysical Foundations of Aquinas on Participation, Unity, and Union offers a systematic treatment of St. Thomas Aquinas's account of the metaphysical relations of unity-to-union and unity-to-participation in God as the key structuring elements to the nature of love and friendship. In general, Aquinas identifies love as the source and summit of the life of each human being. Everything in the created realm issues forth from God's creative love, and the ultimate end of all human persons is the greatest possible union with God. Aquinas contends that the love of friendship allows for the greatest union between two persons; thus, the greatest union with God takes the form of friendship with him.
In addition to the grand metaphysical bookends of human existence, love also serves as the structuring notion of Aquinas's anthropology and practical philosophy. He characterizes much of human life in terms of three basic love love of God, love of self, and love of neighbor. Love of self derives from personal substantial unity. It is logically prior to love of neighbor and serves as a template for the latter. If a person loves himself rightly, he will love others rightly. On the other hand, if he relates to himself through a disordered love, he neither can relate to others rightly nor enter into a deep union with them. Moreover, due to a person's metaphysical participation in God, a person loves himself properly only when he loves God more than himself. Thus, failing to love God appropriately entails an inability to relate to others with a fully developed love. Conversely, the love of God positions a person to relate to others with an authentic love and enter into the union of friendship with them. The volume concludes with a look at personal subjectivity in light of the previous analyses.
This is a competent explanation of Thomas's views on love—particularly self-love, love of neighbor/friend/spouse (including love of children), and love of God. In the final part of the book, Flood tackles the notion of "omnisubjectivity" as put forward by Linda Zagzebski, and demonstrates how her notion of it is necessarily included in Thomas's notion of God's omniscience. Briefly stated, Zagzebski argues that a new term, omnisubjectivity, should be added to the list of God's divine attributes because God doesn't simply know what people are thinking, but he knows what people are feeling subjectively about what they're experiencing. I haven't read Zagzebski's Marquette Lecture on this, but it seems self-evident to me as well that God envelopes every subjective experience we have, and all things participate in His being. Zagzebski's view almost assumes that classical Theology's notion of omniscience makes God into an entity with a far-reaching, penetrating mind, rather than the Ground and Source of absolutely everything, which necessarily and intimately knows everything, whether fact or feeling.
Anyways, Flood's book is helpful in explaining Thomas's (at first surprising) view of how love of others is rooted in love of self. Before one can love a spouse or neighbor, one must love oneself, since union proceeds from unity. In other words, a divided, chaotic, and un-virtuous person who seeks self-destruction will not rightly love others with a well-ordered affection. Necessarily, a person must be in control, must have a subjective desire to live and not to destroy oneself, before he or she is able to seek the good of others and draw towards them (in love).
Then this self-love is rooted in God, because the Source of human love is the preceding gift of divine love. Metaphysically, it is only by participation in the love of God that one can love oneself and thus love others.
For Thomas, love may be accompanied by strong emotions, but love is a conscious action, a knowledge in the mind, decision of the will, and utilization of the virtues.
In self-love is wrongly ordered, then this self-love is not truly self-love, but selfishness and pride. Right self-love is a personal pursuit of the Good in one's life that empowers one or roots one so that he or she can love others. This was helpful for me in understanding why it is so often the case that Christians lose interest in their neighbor and don't seek his or her welfare; it's because the loving subject is not intent on pursuing the Good for himself or herself.
Pretty good, I feel like I understand the principle tenets of Aquinas's thoughts on love as it relates to faith, but the analysis in the book seemed a bit repetitive. By trimming repeated sentences and summaries, you could easily make this shorter, even though it's not long to begin with.