Energy is liberated matter, matter is energy waiting to happen.

I sat on a toilet watching the water run thinking what an odd thing tourism is. You fly off to a strange land, eagerly abandoning all the comforts of home and then expend vast quantities of time and money in a largely futile effort to recapture the comforts you wouldn’t have lost if you hadn’t left home in the first place.

I mused for a few moments on the question of which was worse, to lead a life so boring that you are easily enchanted, or a life so full of stimulus that you are easily bored.

My favourite fellow of the Royal Society is the Reverend Thomas Bayes, an obscure 18th-century Kent clergyman and a brilliant mathematician who devised a complex equation known as the Bayes theorem, which can be used to work out probability distributions. It had no practical application in his lifetime, but today, thanks to computers, is routinely used in the modelling of climate change, astrophysics and stock-market analysis.

18th century scientists, the French in particular, seldom did things simply if an absurdly demanding alternative was available.

You can always tell a Midwestern couple in Europe because they will be standing on a traffic island in the middle of a busy intersection looking at a windblown map and arguing over which way is west. European cities, with their wandering streets and undisciplined alleys, drive Midwesterners practically insane.

I wanted to quit and to do this forever, sleep in a bed and in a tent, see what was over the next hill and never see a hill again. All of this all at once, every moment, on the trail or off.