Outside work, I run. I love it, mostly – it’s my own form of mindfulness. But aching legs and bleeding toes are inevitable. So I was intrigued to hear the ultrarunner Courtney Dauwalter describe in a recent short film how she overcomes pain during a 100-mile race.

Research suggests that ultrarunners like Dauwalter have a higher pain tolerance than the general population. Perhaps their bodies are different, but it also appears to be mental. Dauwalter describes how her mind helps her push through pain. After hours on her feet, she explains, she enters her ‘pain cave’: a place where only mental grit is left.

What particularly struck me was Dauwalter’s approach when inside the cave. Initially, her instinct was to leave. Indeed, she quit her first 100-miler. But now she applies curiosity instead: she explores the cave’s walls, and expands them. ‘I put on my hard hat, I grab a chisel and I imagine going into the very back corners of that cave and just digging into the work,’ she says. ‘Each time I go in the cave, it’s getting bigger for the next visit.’

I find that helpful. Now, when running gets uncomfortable, I remind myself I’ve felt similar before, and survived. Through this, I’m reaching ever-longer distances, curious about how far I can go.

I’m reminded of an observation the novelist Haruki Murakami makes in his memoir What I Talk About When I Talk About Running (2007) – ‘Say you’re running and you start to think, Man this hurts, I can’t take it anymore. The hurt part is an unavoidable reality, but whether or not you can stand any more is up to the runner himself.’

You don’t need to run to find insight from these runners. In life, we all spend some time in our own personal pain caves, especially when stretching ourselves. Pain is unavoidable. The good news is that our tolerance can rise.

Often, forgetfulness is a mere inconvenience: that name, date or task that simply slipped through the cracks. But, sometimes, it’s downright unsettling to forget something. A friend asked me the other day: ‘Remember that hilarious dinner we had there a few years ago?’ And when for the life of me I couldn’t, I felt as if a slice of my existence had been cast into oblivion.

The ancient Greeks harbored a similar, if more pronounced, terror of forgetting. Plato associates forgetting with ‘non-being’, nothingness. Homer’s heroes do heroic things in order to achieve kleos (fame), and thereby defeat the destruction that comes with being forgotten. (As one of the Seven Wise Men said: ‘You will obtain memory through deed.’) Perhaps as a kind of buttress against the fear of forgetting, they anointed Mnemosyne, memory, the mother of the nine muses.

But I enjoyed learning the other day that this negative view of forgetting wasn’t shared by all ancient peoples. Daoism positively celebrates forgetting, indeed raises it to the status of an art. Zhuangzi, a founder of the tradition, urges people to master this art in order to gain a glimpse of Dao (the way), the eternal substratum of our passing world. As the philosopher Xia Chen writes, Zhuangzi’s idea is that the more of the world we’re able to forget – be it morality, history, the arts – the more we’re able to discover our true self, shaving off all that’s inessential to get down to the pith that we ultimately are.

Now, I don’t know if that will be of help when I inevitably confront the next lost memory, but it’s good to remember, if possible, that there’s a certain, subtle benefit in forgetting. ‘Only by forgetting,’ wrote the German philosopher Hans-Georg Gadamer, ‘does the mind have the possibility of total renewal.’