“We can stage our own act on the planet-build our cities on its plains, dam its rivers, plant its topsoils-but our meaningful activity scarcely covers the terrain. We do not use the songbirds, for instance. We do not eat many of them; we cannot befriend them; we cannot persuade them to eat more mosquitoes or plant fewer weed seeds. We can only witness them-whoever they are. If we were not here, they would be songbirds falling in the forest. If we were not here, material events like the passage of seasons would lack even the meager meanings we are able to muster for them. The show would play to an empty house, as do all those falling stars which fall in the daytime. That is why I take walks: to keep an eye on things.”