An Essay on the History of Civil Society, Eighth Edition

Natural productions are generally formed by degrees. Vegetables are raised from a tender shoot, and animals from an infant state. The latter, being active, extend together their operations and their powers, and have a progress in what they perform, as well as in the faculties they acquire. This progress in the case of man is continued to a greater extent than in that of any other animal. Not only the individual advances from infancy to manhood, but the species itself from rudeness to civilization. Hence the supposed departure of mankind from the state of their nature; hence our conjectures and different opinions of what man must have been in the first age of his being. The poet, the historian, and the moralist frequently allude to this ancient time; and under the emblems of gold, or of iron, represent a condition, and a manner of life, from which mankind have either degenerated, or on which they have greatly improved.