PREFACE.

...lead to the discovery of a great fact: there is only a single system of laws. The laws established to govern inorganic non-living matter are the same ones that govern that matter when it takes the form of a human being or a community of people.

In the book published at that time, modern scientific discoveries proving that matter cannot be destroyed original: "indestructibility of matter" were applied to social science for the first time. The difference between agriculture and all other human pursuits was shown: the farmer is always busy making a machine—the soil—whose power increases every year. In contrast, the shipmaster and the wagoner are always using machines—ships and wagons—whose power regularly decreases over time.

As that work demonstrated, the farmer's entire business consists of creating and improving soil. Their ability to make these improvements grows as wealth and population increase. However, the task of fully developing the "law of the perpetuity of matter" the principle that matter is never lost, only transformed and its effect on the law of population was left to the author’s friend, Mr. E. Peshine Smith. An important passage from one of his works can be found on page 150 of this volume.*

Further reflection confirmed the author's belief that the laws described so far were merely parts of a perfectly harmonious system. This system was created to govern matter in all its forms—whether coal, iron, fish, birds, clay, corn, oxen, or humans. He argued that the Creator of the Universe did not need to establish different laws for the same matter. Consequently, physical and social laws must be in harmony with each other. He believed the idea of a unity of law the concept that one set of rules governs both the physical world and human society should be just as provable as the unity of force likely referring to the conservation of energy. To explore this, he used common pheno-

* See also Manual of Political Economy, New York, 1853.
† Principles of Social Science, 3 volumes. Philadelphia, 1857–1859.