Love as Mutual Indwelling

An excerpt from my new book, Affective Knowledge in the Theology of Thomas Aquinas

Both in the early Scriptum and in the mature Summa, Aquinas draws on Dionysius the

Areopagite to express how amor is a “unifying force” (vis unitiva) that seeks its connatural good. In distinction 27 of the third book of the Commentary on the Sentences, this Dionysian definition of love serves as the framing structure for his whole theology of love. In this regard, Aquinas emphasizes how love effects a new union of form. Appealing to Aristotle’s definition of a friend as “another self” (amicus est alter ipse) and the Apostle Paul’s assertion that “whoever adheres to God is one spirit with him” (1 Cor 6:17), Aquinas contends that love entails the union of lover with the beloved in a common form: “Through love the lover becomes one with what is loved, which becomes the lover’s form.” Aquinas speaks of this shared form as a mutual indwelling:

Because love transforms the lover into the beloved, it draws the lover into the interior of the beloved and vice versa, with the result that nothing remains in the beloved that is not united to the lover: just as the form enters deeply into the one informed by it and vice versa, so too the lover in a certain way enters the beloved.

The transformation of the lover is on account of the possession of the new form of the beloved, which has become connatural to him. And, since act follows being, the affect of the lover now acts according to this new form. Aquinas writes,

The lover whose affection is informed by the good itself … is inclined through love to act according to the demands and needs of the beloved…. For since the lover takes up the beloved as though he were the same as himself (amans amatum assumpserit quasi idem sibi), he must, as it were, act as though he were the beloved in all that regards the beloved.