Permaculture challenges what we're doing and thinking - and to that extent it's sedition.

I'd come into town from the bush - after 28 years of field work in natural systems - and become an academic. So I turned my attention to humans, much as I had to possums in the forests.

Permaculture is the conscious design and maintenance of agriculturally productive ecosystems 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.

When you get deep ecologists who are philosophers, and they drive cars and take newspapers and don't grow their own vegetables, in fact they're not deep ecologists - they're my enemies.

There are a few societies that show signs of having been very rational about the physics of construction and the physics of real life. Some of the old middle-Eastern societies had downdraft systems over whole cities, and passive, rapid-evaporation ice-making systems. They were rational people using good physical principles to make themselves comfortable without additional sources of energy.

At least half of every city is wrong. From latitude 30 degrees to latitude 60, say, you've got to have the long axis of the house facing the sun. If the land is cut up into squares, that makes half of all houses wrong if they face the road. Even houses way in the country, and way off the road, face the bloody road. And from there, you just go wronger all the way.

When the idea of permaculture came to me, it was like a shift in the brain, and suddenly I couldn't write it down fast enough.