This is the first of three pieces on the theological virtues. They are treated together because Saint Paul treats them together — faith, hope and love abide, and the greatest of them is love (1 Cor 13:13) — and separately because each fails in its own way.
What the virtue is
The Catechism defines faith as the theological virtue by which we believe in God and all that he has revealed, and by which the Church proposes it for our belief (CCC 1814). Two things in that definition are easy to skate past.
The first is that faith is a virtue, which in the classical sense means a stable disposition — something you can have more or less of, something that strengthens by exercise and atrophies by neglect. It is not a switch.
The second is that it is theological, meaning infused rather than acquired. It is not built up the way patience is built up. Its origin is not in us. This matters enormously for what follows, because it means the state of your faith is not simply a report on how hard you have been trying.
What it is not
Faith is not certainty in the psychological sense — the felt absence of doubt. This confusion does a great deal of damage. If faith just is the feeling of certainty, then the arrival of doubt is the departure of faith, and a person in a dry season concludes they have lost something they have not lost.
The letter to the Hebrews describes faith as the assurance of things hoped for, the conviction of things not seen (Heb 11:1). Not seen is doing real work in that sentence. A faith whose object were plainly visible would not be faith; it would be observation. The obscurity is structural, not a defect in the believer.
Nor is faith the same as its articulation. Plenty of people hold the faith firmly and explain it badly. The inability to win an argument about the Trinity at half past eleven at night is not evidence of anything except the hour.
How it actually fails
If doubt is not the failure mode, what is? I would suggest two.
Presumption of possession. Treating faith as a thing you obtained once and now own, rather than a relationship being sustained. This is the failure that does not feel like failure, which is what makes it dangerous. Nothing hurts, and the thing quietly stops being load-bearing — until something happens that requires it to bear load.
Refusal of the intellect. The opposite error: deciding that since faith is not a conclusion, thinking about it is beside the point. The Church has never taught this. She canonised Aquinas. Faith seeks understanding; a faith that has stopped seeking has stopped doing something faith does.
What to do in a dry season
Very little, and keep doing it. The season passes or it does not, but the practices are available either way: continue in the sacraments, continue in the office or the Rosary or whatever the fixed thing is, and be honest in prayer about the dryness rather than performing a fervour you do not have. God is not deceived by the performance and you are exhausted by it.
Saint Thérèse of Lisieux spent the last eighteen months of her life in what she described as a darkness about heaven, and continued. That is not a consolation exactly. But it is a correction to the idea that the saints felt certain and we do not.
Next in this series: hope, and why it is the virtue most often mistaken for optimism.