Abstract
In this article, I focus on the circular relationship that, in his 1998 encyclical, Jean Paul II argued there is between faith and reason. I first note that this image of circularity needs some explaining, because it is not clear where exactly the circular process begins and ends. I then argue that an explanation can be found in Aquinas’s reflection on the gift of understanding. Aquinas referred to the virtue of faith as caused by God, which promotes human reason, and this in turn strengthens the certainty of faith.