“Sentiment without action is the ruin of the soul.”

“What we need now are heroes and heroines, about a million of them, one brave deed is worth a thousand books. Sentiment without action is the ruin of the soul.”

“Philosophy without action is the ruin of the soul. One brave deed is worth a hundred books, a thousand theories, a million words. Now as always we need heroes. And heroines! Down with the passive and the limp.”

“As a confirmed melancholic, I can testify that the best and maybe only antidote for melancholia is action. However, like most melancholics, I suffer also from sloth.”

“Poor Hayduke: won all his arguments but lost his immortal soul.”

“We can have wilderness without freedom; we can have wilderness without human life at all, but we cannot have freedom without wilderness, we cannot have freedom without leagues of open space beyond the cities, where boys and girls, men and women, can live at least part of their lives under no control but their own desires and abilities, free from any and all direct administration by their fellow men.”

“A world without huge regions of total wilderness would be a cage; a world without lions and tigers and vultures and snakes and elk and bison would be - will be - a human zoo. A high-tech slum.”