The creation and the use of wealth are everywhere governed by natural laws, and these, as discovered and stated, constitute the science of Economics. Some of them come into operation only when men live in more or less civilized societies and work in an organized way, while others are operative wherever men work at all. Every man who lives must have something that can be called wealth, and, unless it is given to him, he must do something in order to get it. A solitary hunter, living in a cave, eating the flesh of animals and clothing himsejf in their skins, would create wealth and use it; but he would not take part in a social kind of industry. What he does could not be described as a bit of “social,” “national” or “political” economy. Yet the gaining of his living would be an economic operation and would involve a creating and using of wealth. A statement of the laws governing the processes by which such a man makes the earth yield to him means of support and comfort would constitute a Science of the Economy of Isolated Life, which is a part of the general Science of Economics.
Source link: http://archive.mises.org/5783/clarks-essentials-of-economic-theory/