Its chief use is only to discover the constant and universal...

Its chief use is only to discover the constant and universal principles of human nature, by showing men in all varieties of circum- stances and situations, and furnishing us with materials from which we may form our observations and become ac- quainted with the regular springs of human action and be- haviour.

These records of wars, intrigues, factions, and revolutions, are so many collections of experiments, by which the politician or moral philosopher fixes the prin- ciples of his science, in the same manner as the physician or natural philosopher becomes acquainted with the nature of plants, minerals, and other external objects, by the ex- periments which he forms concerning them.

Nor are the earth, water, and other elements, examined by Aristotle, and Hippocrates, more like to those which at present lie under our observation than the men described by Polybius and Tacitus are to those who now govern the world. Should a traveller, returning from a far country, bring us an account of men, wholly different from any with whom we were ever acquainted; men, who were entirely divested of avarice, ambition, or revenge;