"I CAN'T BELIEVE YOU DID THAT," said my dad. "EUGH! YOUR MOUTH IS GOING TO SWELL UP NOW AND YOU WON'T BE ABLE TO EAT AGAIN. AND I SAW A DOG DO A WAZ THERE EARLIER."

My dad, my mum, my girlfriend and I were walking along a footpath leading away from Creswell Crags, a limestone gorge on the border between Derbyshire and Nottinghamshire whose caves show evidence of life in the paleolithic era, and I had just eaten a nettle. It wasn't the first nettle I'd ever eaten, but it was the first one I'd eaten unassisted, which is arguably a more seminal moment in a nettle eater's life. A week earlier, on a foraging holiday in Wales, a friend had shown me the exact way to neutralise the sting of the leaves, by folding them inwards, then placing them beneath your molars, but a throbbing feeling in the inside of my cheek told me I hadn't quite got it right.

"It's lovely actually," I said, swallowing. "Really tasty." I could now feel a second prickly sensation somewhere just north of my gallbladder.

I'd eaten it the nettle to prove a point, which was that, by eating it, I was changing the course of history. It was important that I didn't let on that I'd been stung by the nettle, as I felt it would weaken my position. A few minutes earlier, to the slight consternation of other ramblers, my dad had drawn an eighty yard line in the gravel of the main footpath at Creswell, to illustrate man's status as a footnote in history's greater scheme. This had led him on to one of his favourite topics, predetermination: his belief - from an atheist's perspective - that all choice is just an illusion.

"THAT PROVES NOTHING," he told me. For the last 30 minutes he'd been wearing a false moustache, purchased from the gift shop at nearby Welbeck Abbey, and it wobbled precariously as he spoke. "YOU JUST THINK YOU CHOSE TO EAT THE NETTLE. HOW CAN YOU BE SURE IT WASN'T ALWAYS GOING TO HAPPEN?"

Using my free will, I chose to let it go. It's hard to have a serious debate with a man wearing a plastic Salvador Dali moustache and I know that when my dad's discussing predetermination there's little you can do to make him see sense. In 1984, he wound his friend Malcolm up so much by discussing predetermination that Malcolm pushed him off a small cliff in France. It's one of the main signs that he's really enjoying a country walk, along with rhapsodising about bulls and retelling stories about the O'Dohertys, an abundant neighbouring family on the council estate where he grew up.

For a long time, I declined to go rambling with my parents. As a golfer, my take on walking was the opposite of Mark Twain's: I saw it as golf without the interesting bits. These days, though, I rarely feel more in touch with what's important in life than when I'm walking. It has the same positive, centering effect as a meditation course I once went on, with the arguable bonus that nobody tells me to take deep breaths and imagine my nostrils are caves. That said, the meditative aspect is lessened when I walk with my dad. His lecture-walking has a raucous freeform jazz quality to it and can often vault across generations and continents in the space of one breath.

"KEEP IN!" he barked, as we walked along the grass verge back to Welbeck. "I'D LOVE TO GO TO ZAIRE. LOOK AT THE SIZE OF THOSE STABLES! THE O'DOHERTYS ALWAYS HAD ANIMALS IN THEIR HOUSE. ONCE I LIFTED UP THE SOFA AND THERE WERE ABOUT 20 PINK MICE. "

I'd been interested in visiting Welbeck due to its association with William Cavendish-Scott-Bentinck, the eccentric 19th-century duke who built an underground maze beneath its grounds and whose life I'd read about in Mick Jackson's brilliant novel, Underground Man. It was one of two literary pilgrimage rambles I'd gone on recently, the other being a WG Sebald-inspired stroll along the stretch of the Suffolk coastline around Covehithe: an eerie, eroded landscape featuring dead, still-rooted trees poking out of the waves, a saltwater lagoon and a B road snapped like a piece of Scalextric above cliffs that crumble like stale coffee cake at the touch of a hand.

The book that Sebald wrote about his rambles through Suffolk, The Rings Of Saturn, was one of the reasons I began walking: a magical, atmospheric mixture of travel writing, history and memoir. Sebald set off from Norwich in 1992, seemingly with no real goal in mind, and walked the Suffolk coast before heading inland towards Harleston. On his journey he discusses everything from Rembrandt to Conrad to the herring industry, in the process inspiring a new generation of psychogeographer authors and proving that the most unpitchable books are often the best. It's hard not to speculate about the way Sebald laid the project out to his agent. I imagine their conversation went something like this:

Sebald: "Imagine Tony Hawks's Round Ireland With A Fridge, but set in Suffolk, with large digressions on trauma, shoddy black and white photos of Lowestoft terraces and Bosnians being hanged in death camps and no fridge."

Agent: "I think we should start seeing other people."

I would like to have met Sebald, but he died in a car crash at the end of 2001, a few weeks after I moved to Norfolk. I'm far from alone in my fascination with him, as is evinced by Patience After Sebald, Grant Gee's grainily atmospheric documentary about The Rings Of Saturn, which features several psychogeographer writers talking about their Sebald pilgrimages - many of which I suspect, unlike mine, didn't feature a return journey detour via the Beccles branch of McDonalds.

I thought my dad might like the film but he didn't seem to hear me when I tried to tell him about it at Welbeck. He was caught up in a monologue about Nottinghamshire collieries, which had somehow segued into a story about the toad that was still periodically living in an old shoe of his: a state of affairs I was already aware of due to the Post-it note he'd left on the shoe which said 'TOAD IN SHOE!'

"THERE WAS A DIFFERENT TOAD, TOO," he said. "THAT ONE LIVED ON THE COMPOST HEAP. I USED TO PUT A BLANKET OVER IT AT NIGHT AND TUCK IT IN. HAVE YOU FIXED YOUR ROOF YET? DON'T GO UP THERE YOURSELF. KEITH HARRIS AND ORVILLE DIED DOING THAT."

I thought about my fantasy walks with Sebald: a melancholy moustachioed German man, who, like my dad, would've been in his 60s by now. Would he have been a slightly more attentive companion? Perhaps. But I was probably romanticising unrealistically. Who's to say a solitary type like Sebald would have wanted a companion? My dad, on the other hand, was always grateful for a sounding board, and had some great stories about feral 1950s children setting fire to bins. He even had a moustache.

Ultimately, I couldn't complain. Here, in true Sebaldian fashion, was local history, memoir, world history and fiction, all mixed together: a classic example of the digressive spirit of walking. Whichever way you looked at it, it was all good psychogeography.

• Tom Cox's latest book, Talk to the Tail, featuring more stories about his dad, is out in paperback. Follow him on Twitter at @cox_tom.