It is therefore evident that in _using_ Capital so as to make Labour more efficacious, as distinct from _wasting_ Capital so as to make Labour nugatory, some other human faculties are involved distinct from the faculty of Labour; and I have employed, except when it would have been mere pedantry to do so, the term “Human Exertion” instead of the term “Labour,” because the former includes those other faculties, and the latter does not; or, if it includes them, it entirely fails to distinguish them, and merely confounds them with faculties from which they fundamentally differ. Thus, when I pointed out in the last chapter that Capital, in so far as it increased the productivity of Labour, was mental and moral energy as applied to muscular energy, I might have said with equal propriety, had my argument advanced far enough, that it was one kind of Human Exertion guiding and controlling another kind. Here we come to the great central fact which forms the key to the whole economic problem: the fact that in the production of wealth two kinds of Human Exertion are involved, and not, as economists have hitherto told us, one—two kinds of exertion absolutely distinct, and, as we shall see presently, following different laws. [Sidenote ◆1 Economic writers vaguely recognise this fact, but have never formally expressed it, or made it a part of their systems.] [Sidenote ◆2 They confuse all productive exertion together under the heading of Labour.] ◆¹ Economic writers, like the world in general, do indeed recognise, in an unscientific way, that productive exertion exhibits itself under many various forms; but their admissions and statements with regard to this point are entirely confused and stultified by the almost ludicrous persistence with which they classify all these forms under the single heading of Labour. Mill, for instance, says that a large part of profits are really wages of the labour of superintendence. He speaks of “the labour of the invention of industrial processes,” “the labour of Watt in contriving the steam-engine,” and even of “the labour of the savant and the speculative thinker.” ◆² He employs the same word to describe the effort that invented Arkwright’s spinning-frame, and the commonest muscular movement of any one of the mechanics who assisted with hammer or screwdriver to construct it under Arkwright’s direction. He employs the same word to describe the power that perfected the electric telegraph, and the power that hangs the wires from pole to pole, like clothes-lines. He confuses under one heading the functions of the employer and the employed—of the men who lead in industry, and of the men who follow. He calls them all labourers, and he calls their work Labour. [Sidenote ◆1 But practically, Labour means muscular or manual exertion.] [Sidenote ◆2 Mental and moral exertion, as applied to production, must therefore be given another name:]