MOTHER TERESA of Calcutta wanted the letters destroyed that charted the desolation of her spiritual life. They were not; they were published in 2007. They revealed that, at the same time as her work for the poorest of the poor was turning her into a world celebrity, her inner life was a private hell. The absence of any sense of God’s presence in prayer or at the eucharist brought her to the point where she doubted God’s very existence.

There are various ways in which this experience has been interpreted. For some, it was a process of purification. Mother Teresa was aware of a tendency to pride — the typical pride of the high achiever. Losing the sense of God was then either a way in which she unconsciously punished herself, or in which God held her pride in check.

A more cynical interpretation came from the atheist apologist Christopher Hitchens. He thought that Mother Teresa had simply come to the recognition that religion was a human invention. She did not experience God because, deep down, she realised that God did not exist. She herself seems to have entertained this bleak possibility, speculating in her letters that if God did not exist there was no such thing as the soul, and that Jesus, too, was not real. But she did not pursue this line of thought. She seems, in the end, to have accepted the loss of spiritual consolation as a sacrifice that God was asking of her.

She was not the only modern saint to have had such an experience. A hundred years before Mother Teresa, St Thérèse of Lisieux was called to silence and anonymity, a “little way” of love and simplicity. In her last years, racked with tuberculosis, she went through a period of profound darkness, doubting the promise of heaven.

I wonder whether this spiritual darkness might not be a kind of prophetic sign. Religion in the modern era can be a noisy, aggressive business. The faithful of all faiths have plenty to say in self-justification, and sometimes in condemnation of others. Mother Teresa was called to an extravagant public compassion; Thérèse of Lisieux to a hidden, childlike faith.

What speaks in both of them is not words, but silence and deeds. These are, perhaps, the only truthful response to the challenge of contemporary atheism. Paradoxically, it may be that it is only the prayed life that can embrace atheism in love, and recognise in it the long human disappointment in false gods.

The words given in prayer to the Staretz Silouan resonate: “Keep your mind in hell, and do not despair.” If that is what Mother Teresa was called to do, it should be seen as part of her vocation.