All we can say now is, that, even now, 600 persons could easily live on a square mile; and that... 1,000 human beings—not idlers—living on 1,000 acres could easily, without... overwork, obtain... a luxurious vegetable and animal food, as well as the , wool, silk and hides necessary for their clothing. As to what may be obtained under still more perfect methods—also known but not yet tested on a large scale—is better to abstain from any forecast: so unexpected are the recent achievements of intensive culture.
— PETER KROPOTKIN