Ten years after her death, Mother Teresa of Calcutta still fascinates a world which fails to share her faith.  Last week she appeared on the cover of Time magazine with the headline "the secret life of Mother Teresa". But the article contained, not reminiscences of her self-sacrificing care for the poor, but startling documentation of inner spiritual desolation decade after decade. 

“I am told that God loves me – and yet the reality of darkness & coldness & emptiness is so great that nothing touches my soul”. These words are taken from correspondence between Teresa and her confessors and superiors over 66 years,  which is being published as Mother Teresa: Come Be My Light.

But the lives of people like Teresa show the abiding wisdom of this embrace of pain, even spiritual pain. They radiate peace and joy even while undergoing their own hidden Calvaries. 

They are not sentiments that one expects from a saintly nun who spent hours each day in prayer and the rest of her time in tending the sick, the poor and the abandoned. While no adult should think of God as a celestial Santa Claus, ever ready to indulge our most selfish petitions, are we meant to address as "our Father" an entity that would allow this much interior pain in his "beloved"? The atheists of the global village were quick to say "I told you so." They used Teresa's desolation as another proof that believers are deluding themselves. Christopher Hitchens, author of a nasty biography of a woman whom everyone else on the planet loved, had a simple message to the faithful in his column in Newsweek: God is not great and Teresa is not His prophet.

According to Hitchens and his fellow apostle of atheism, Sam Harris, Christianity is a figment of the human imagination so powerful that its adherents have no eyes to see its flaws, nor ears to listen to his refutation. It leads people to believe flat contradictions in the very teeth of the evidence. Exhibit A in their debunking tirades is Mother Teresa, who preached God to others, even though she felt racked by doubt herself.

There are more things in heaven and earth than in your philosophy, my dear fellow, but let us take a closer look at your reasoning.

To begin with, such arguments are largely circular: precious little evidence is given for claims that there is no evidence. Dismissing the work of brilliant thinkers like Thomas Aquinas or Elizabeth Anscombe, as Sam Harris does, as “strenuous and unconvincing theology” is a bit rich. Even flakier, however, is the notion that if Mother Teresa wrestled with her faith, then Christianity is clearly baloney. This is a clear example of the logical fallacy called "affirming the consequent".

This is how it runs: If Christianity is baloney, then its adherents will have trouble believing it. Christianity’s finest adherents have trouble believing it. Therefore Christianity is baloney.

But other causes could have been involved. Consider the following counter-example: If it is raining the lawn will be wet. The lawn is wet. Therefore it is raining. Clearly this is wrong.  Someone could have turned on the sprinkler.

So too, Mother Teresa’s “doubts” in  the existence of God could have had other causes than God's non-existence. Doubt and certitude are subjective reactions to the evidence. The father of modern philosophy,René Descartes, doubted the existence of his hands but was sure about the existence of his soul. But the reality of the existence of either hands or soul does not stand or fall on any one person’s emotion-charged assessment of the evidence for and against this particular proposition.

Atheists will be quick to say that there is no God; no wonder Teresa had trouble appreciating His existence. But this is simple to the point of being simplistic. For a pop psychologist like Hitchens all saints are basket cases: hearing voices means schizophrenia, spiritual elation followed by aridity means manic depression. But this ignores the facts about the lives of men and women like Teresa.

Atheists may scoff at the Christian belief that happiness comes not from health, success, money or self-esteem but from the cross. But the lives of people like Teresa show the abiding wisdom of this embrace of pain, even spiritual pain. They radiate peace and joy even while undergoing their own hidden Calvaries. Theologians refer to this phenomenon as a "dark night" of sense or of spirit. The removal of pride and attachments is part of a long and painful chemotherapy of the soul. Catholics believe that God uses purgatory to prepare sinful souls for the joys of heaven. Teresa may have bypassed purgatory by being purified here below.

Saints like the recently-canonised Josemaría Escrivá often averred that they were constantly going against the grain in their service of the Lord. Far from being a senseless exercise in self-deception, this purification from the dangers of wallowing in smug altruism leads to greater self-knowledge and dedication. It has a familiar parallel in the sleepless exhaustion of mothers and fathers caring for a wailing infant. They may not feel the glow of love at 3am -- but it is there all the same.

Does the revelation of Mother Teresa's inner agony mean that she should be promoted as the patron saint of sceptics?

No -- because she was no sceptic. When a mystic writes about experiences for which language barely has words she will inevitably say things that cannot be taken literally. Hallelujahs on the lips do not necessarily imply faith.  What showed the sincerity of Teresa's faith was that she both said Hallelujah and worked doggedly, tirelessly, perseveringly for Christ. If she spoke of a lack of faith and dryness in her prayer, these were protests directed to her God in her prayer.  She knew that Christ had redeemed souls by suffering a similar desolation on his cross. And she wanted nothing less than to imitate her Lord. "If this brings You glory — if souls are brought to you — with joy I accept all to the end of my life," she wrote.

Mother Teresa’s good works were proof of her faith. What more evidence do you need?

Dr Richard Umbers is a Catholic priest. He lectures in philosophy in Sydney.