According to Bill Mollison:
"Permaculture (permanent agriculture) is the conscientious design and maintenance of agriculturally productive eco-systems which have the diversity, stability, and resilience of natural ecosystems. It is the harmonious integration of landscape and people providing their food, energy, shelter, and other material and non-material needs in a sustainable way. Without permanent agriculture there is no possibility of a stable social order.
Permaculture design is a system of assembling conceptual, amterial, and strategic components in a pattern which functions to benefit life in all it's forms.
The philosophy behind permaculture is one of working with, rather than against, nature; of protracted and thoughtful observation rather than protracted and thoughtless action; of looking at systems in all their functions, rather than asking only one yield of them; and of allowing systems to demonstrate their own evolutions." -Permaculture: A Designers' Manual, 1988
According to David Holmgren: