something man does not want. (We are concerned only with labor expended for economic purposes. Sometimes man will find pleasure in exertion itself, as in taking a walk. And sometimes he "likes his job," finds enjoyment in the doing, regardless of any other returns. The exhilaration resulting from the doing is the profit he seeks. But he does not labor for the sake of laboring.) To avoid exertion, man might, like other animals, curtail his appetites to the barest necessities, to the things that make existence possible and that can be had with the minimum of effort. (Nothing can be had with no effort.) He is, however, not so constituted, being driven by an ever-expanding curiosity to seek new gratifications, and he is ever looking to nature to tell him how he can acquire them with less labor. He invents labor-saving devices; he expends labor to save labor. He puts in "overtime" — or labor in excess of what is necessary to keep him alive — in the production of things that will save him labor in his future enterprises or will enable him to better his circumstances. We call those things capital. As far as we know, man has always been a capitalist, a storer up of labor, and we cannot conceive of a time when he was not making such tools. Thus, the stone axe which he made to subdue an edible beast became, after centuries of reflection and trial-and-error, a cleaving knife and the Chicago stockyards. Capital accumulation has always been man's career. We do not know of a noncapitalistic man or a noncapitalistic Society. In any distinction between primitive man and civilized man we use as a yardstick their relative accumulations and use of capital.
A natural law is derived from observation of the ways of nature. Its first characteristic is invariability — it always happens that way; there are no exceptions. And since, in everything he does, as far back as we have any knowledge of him,