A soft rain hammers at the window. I’ve pushed the couch to the other side of the coffee table because I need to get closer to my floor lamp. In front of me is a stack of 40 student essays, unopened and ungraded. The water I boiled for tea went cold an hour ago and I’m looking up the age of celebrities on Wikipedia. David Hasselhoff (born 17 July 1952). Dannii Minogue (born 20 October 1971). Has my afternoon been wasted? Is this … procrastination?

Today the P-word has a bad reputation. Psychologists link it with increased anxiety, diminished self-esteem and depression. And magazines (like the ones I just sorted into a date-ordered stack) feature articles with headlines such as “How to Stop Procrastinating, NOW!” Am I one of the 20% of the population with “chronic procrastination”, the lifelong tendency to avoid doing the things I should be doing? A few years ago, this would have alarmed me – but now I no longer worry. I embrace days like this. Because an obscure idea I discovered in a work of medieval theology has taught me how to relax.

For over a decade I’ve been researching the history of the seven deadly sins. This is the self-help system, devised in the Egyptian desert over 1,600 years ago, that claimed to identify the basic habits of the mind. It turns out that the medieval wisdom applied to these habits – pride, envy, anger, sloth, avarice, gluttony and lust – can be mapped on to the modern world pretty well. Studying pride taught me how to deal with narcissists, for example. But it was the fourth sin, sloth, that really opened my eyes.

Sloth never meant “laziness”. This was always a bad English translation. The original Greek word was acedia, and according to the Summa de vitiis, or “summary of the vices” – a bestseller from the 1230s – it was really a combination of boredom, depression, anxiety and despair. It’s when you become a rudderless ship, knowing where your day, or your week, or your life ought to be steering, but unable to make it happen. Sloth isn’t boredom without a direction. It’s boredom in spite of a direction.

Across the self-help texts of the 1200s and 1300s I have discovered two approaches to procrastination: one is destructive, but the other is inspiring, even life-affirming. And the difference depends on how, in those wasted moments, we engage our hearts.

Dante Alighieri, the Florentine author of The Divine Comedy, described the “wrong” approach as one of sleepwalking towards disaster. While climbing Mount Purgatory, Dante’s pilgrim stops for a nap on the terrace of Sloth. In a dream he sees a woman, who sings to him with the most beautiful voice. The pilgrim is spellbound. But then Virgil (his guide up the mountain) lifts up the woman’s dress to reveal a band of rotting flesh beneath. Dante’s message was lurid but powerful. Boredom works by anaesthetising our minds, leaving us open to manipulation. We become vulnerable to chasing after things that, although shiny and seductive, are often rotten at the core.

What was the answer, then? The best medieval theologians never believed it was possible to expunge any of the deadly sins altogether. They knew that they were hard-wired, constituting the impulses that make us all human. And so they felt the “right” approach to something like procrastination was to let it happen, but to direct it towards something that does us (and those around us) some good.

Bernard of Clairvaux, the greatest monastic intellectual Europe has ever produced, put it best: living a good life is like running a marathon over rough terrain. We know the direction we should be travelling and we know where the finish line is, but we can’t expect to run the whole way at the same speed. There will be days of apathy, of boredom, of numbness. And on those days we need to make sure we stay awake and alert. So long as we engage our brains, there’s a sweetness even in the most trivial distraction that can awaken our sleeping hearts.

Dante (who put Bernard of Clairvaux right at the top of Paradise in his Divine Comedy) knew exactly what this meant. In his philosophical treatise Convivio, he describes a time in his life of acute boredom and depression; a “strangeness” that left him unwilling to do any of the things he used to love. Distracting himself, Dante picked up two books: Boethius’s Consolation and Cicero’s On Friendship. And although he was only hoping to extinguish his misery, in the process of “looking for silver” he struck “gold”. The books awakened a love of philosophy and gave him a life-changing lesson – that so long as he wrote in pursuit of truth, rather than to justify his desires or ambitions, writing would never make him miserable again.

What Dante hit on was medieval culture’s magic formula: using boredom as a portal to self-discovery. In so many medieval poems – in Wolfram von Eschenbach’s Parzival or in The Pearl – the hero begins in a state of dreamlike distraction. Parzival wants to be a heroic knight, but wanders restlessly through the countryside; the grieving narrator of The Pearl hunts in a garden, gazing in distraction at the plants and flowers. But then, through these diversions, the heroes experience breathtaking revelations. Parzival’s wandering brings him to the holy grail, and The Pearl’s narrator, while absorbed by the greenery, slips into a dream vision of paradise where he meets his lost daughter again. Both find much more than what they thought they were looking for. And both, by straying from the straight path, come to a deeper understanding of themselves.

So, on these afternoons of lethargy, the answer is to accept procrastination as a chapter break, a palate cleanser. And to remember that so long as we stay awake there’s gold to be found, even on David Hasselhoff’s Wikipedia page. I’ll still grade those student essays, of course. But today I’ll wait for the distraction to pass, and accept that a little procrastination is essential to emotional growth. “A field that gives abundant fruit after thorns and thistles,” as the Summa de vitiis says, “is more loved than a field that, although it never had any thorns or thistles, never really gave much fruit at all.”

Dr Peter Jones is a historian and author of Self-Help from the Middle Ages (Doubleday).

Further reading

The Divine Comedy by Dante Alighieri (Penguin Classics, £12.99)

The Consolation of Philosophy by Anicius Boethius (Penguin Classics, £10.99)

The Wandering Mind: What Medieval Monks Tell Us About Distraction by Jamie Kreiner (Liveright, £23.99)