This difference in kind, between labour and other commodities, is the justification of trade unionism, and the explanation of how it is that a man can logically be at the same time a free trader and a trade unionist. Except the trade unionists and the professed socialists, however, no great body of persons seems to have perceived this peculiarity of labour; and while underpayment is very generally deplored, the various efforts of the benevolent are mostly directed either towards supplementing inadequate wages or towards transferring the underpaid to other branches of work, rather than towards securing better payment for the work at present done. In the eyes of the average Briton, the settling of wages by free competition appears, for some unexplained reason, as a sacred and permanent principle. Perhaps, if this attitude could be exhaustively analysed, we should find at its root a vague respect for “the laws of political economy,” which respect is, in the last resort, but the result of a confusion of mind about two aspects of the word “law.” Laws in the moral world are, of course, different from laws in the scientific world. The moral (or social) law is a command; the scientific law merely a statement of effects. This we see, plainly enough, when the effects are material and immediate. We do not dream of regarding the law that fire burns as a command to put our fingers in the flame. But when we come to consider the results of wide-spread human action, we seem to ourselves to be in the region rather of morals than of science, and without clearly realising our attitude, we begin, many of us, to regard the laws that govern these matters rather as precepts to be obeyed than as sequences to be avoided. The law that free competition in labour leads to starvation wages is a law of the same kind as the law that a dose of prussic acid leads to death; and the conclusion to be drawn in each case is that if we wish to avoid the result we must avoid the cause. Persons who are not desirous of committing suicide must abstain from prussic acid; persons who desire to see underpayment vanish must resist free competition in labour.