The rhythm of walking generates a kind of rhythm of thinking, and the passage through a landscape echoes or stimulates the passage through a series of thoughts. The creates an odd consonance between internal and external passage, one that suggests that the mind is also a landscape of sorts and that walking is one way to traverse it. A new thought often seems like a feature of the landscape that was there all along, as though thinking were traveling rather than making.
Rebecca Solnit (2001). “Wanderlust: A History of Walking”, p.11, Penguin