Just as, when he says that labour is the sole productive agency, he assumes the gifts of nature, which provide it with something to work upon, so, when he conceives of labour as the effort of hand and muscle, he assumes a human mind behind these by which hand and muscle are directed.

Such being the case, he expressly admits also that mind is in some cases a more efficient director than in others, and is able to train the hands and muscles of the labourer, so that these acquire the quality which is commonly called skill.

Ruskin, who asserted, like Marx, that labour is the sole producer, used in this respect a precisely similar argument.

He defined skill as faculty which exceptional powers of mind impart to the hands of those by whom such powers are possessed, from the bricklayer who, in virtue of mere alertness and patience, can lay in an hour more bricks than his fellows, up to a Raphael, whose hands can paint a Madonna, while another man's could hardly be trusted to distemper a wall evenly.
Now, in skill, as thus defined, we have doubtless a correct explanation of how mere labour--the manual effort of the individual--may produce, in the case of some men, goods whose value is great, and goods, in the case of other men, whose value is comparatively small; and since some epochs are more fertile in developed skill than others, an equal amount of labour on the part of the same community may produce, in one century, goods of greater aggregate value than it was able to produce in the century that went before it.

But these goods, whose superior value is due to exceptional skill--or, as would commonly be said, to qualities of superior craftsmanship--though they form some of the most coveted articles of the wealth of the modern world, are not typical of it; and from the point of view of the majority, they are the part of it which is least important.