In his exegesis of Romans 8:15-16, Thomas Aquinas asks how it is that the Holy Spirit bears testimony in us that we are the children of God. He responds that the Spirit bears testimony “through the effect of filial love he produces in us. ” At least in some circumstances, Aquinas suggests, we can come to know God through our experience of loving him. But Aquinas, following a long tradition, teaches that we love things insofar as we know them as good (cf: I-II, q.9, a.1, corpus and ad.3). How then can love give rise to knowledge?Aquinas’s teaching in the Summa Theologica on the Holy Spirit’s gift of wisdom provides a key to this question. The gift of wisdom makes use of the love of charity to know God (II-II, q.45). Charity, by making us “co...