The most important characteristic of an organism is that capacity for internal self-renewal known as health. There are two organisms whose processes of self-renewal have been subjected to human interference and control. One of these is man himself (medicine and public health). The other is land (agriculture and coservation). The effort to control the health of land has not been very successful.

An Ecologist lives in a world of wounds.

Land health is the capacity for self-renewal in the soils, waters, plants, and animals that collectively comprise the land.

I have purposely presented the land ethic as a product of social evolution because nothing so important as an ethic is ever 'written'… It evolves in the minds of a thinking community.

To keep every cog and wheel is the first precaution of intelligent tinkering.

No important change in ethics was ever accomplished without an internal chage in our intellectual emphasis, loyalties, affections, and convictions.

The elemental simplicities of wilderness travel were thrills. They represented complete freedom to make mistakes. The wilderness gave those rewards and penalties, for wise and foolish acts against which civilization has built a thousand buffers.