The practical outcome of the scientific reasoning of Marx is summed up in the formula which has figured as the premise and conclusion of every congress of his followers, of every book or manifesto published by them, and of every propagandist oration uttered by them at street-corners, namely, “All wealth is produced by labour, therefore to the labourers all wealth is due”—­a doctrine in itself not novel if taken as a pious generality, but presented by Marx as the outcome of an elaborate system of economics.

The efficiency of this doctrine as an instrument of agitation is obvious.  It appeals at once to two universal instincts:  the instinct of cupidity and the instinct of universal justice.  It stimulates the labourers to demand more than they receive already, and it stimulates to demand the more on the ground that they themselves have produced it.  It teaches them that the wealth of every man who is not a manual labourer is something stolen from themselves which ought to be and which can be restored to them.

Now, whatever may be the value of such teaching as a contribution to economic science, it illustrates by its success one cardinal truth, and by implication it bears witness to another.  The first truth is that, no matter how desirable any object may be which is obtruded on the imagination of anybody, nobody will bestir himself in a practical way to demand it until he can be persuaded to believe that its attainment is practically possible.  The other is this:  that the possibilities of redistributing wealth depend on the causes by which wealth is produced.  All wealth, says Marx, can practically be appropriated by the labourers.  But why?  Because the labourers themselves comprise in their own labour all the forces that produce it.  If its production necessitated the activity of any persons other than themselves, these other persons would inevitably have some control over its distribution; since if it were distributed in a manner of which these other persons disapproved, it would be open to them to refuse to take part in its production any longer; and there would, in consequence, be no wealth, or less wealth, to distribute.

Let us, then, examine the precise sense and manner in which this theory of labour as the sole producer of wealth is elaborated and defended by Marx in his Bible of Scientific Socialism.  His argument, though the expression of it is very often pedantic and encumbered with superfluous mathematical formulae, is ingenious and interesting, and is associated with historical criticism which, in spite of its defects, is valuable.  Marx was, indeed, foremost among those thinkers already referred to who first insisted on the fact that the economic conditions of to-day are mainly a novel development of others which went before them, and that, having their roots in history, they must be studied by the historical method.  He recognised, however, that for practical purposes each age must concern itself