Faith

In the theology of Thomas Aquinas, faith (fides) is the first of the three theological virtues. It is not blind feeling but an act of the intellect — one that reaches, under the movement of grace, toward truths that reason alone cannot see. The Summa treats it across sixteen questions; a few of its answers, in Aquinas’s own words, follow.

What is faith?

Faith is the substance of things to be hoped for, the evidence of things that appear not.

— Summa Theologica, IIa-IIae Q.4, a.1 (citing Hebrews 11:1)

How does Aquinas define faith itself?

Faith is a habit of the mind, whereby eternal life is begun in us, making the intellect assent to what is non-apparent.

— Summa Theologica, IIa-IIae Q.4, a.1

Is faith an act of the intellect, or of the will?

To believe is an act of the intellect inasmuch as the will moves it to assent.

— Summa Theologica, IIa-IIae Q.2, a.1

Is faith a virtue?

Since it is by faith that the intellect assents to the truth at the command of the will, faith is a virtue, for it makes its possessor’s act good, and directs the intellect to its due end — God, the First Truth.

— after Summa Theologica, IIa-IIae Q.4, a.5