The new apparatus is an addition to the world's wealth, not because so many scraps of wood, brass, nickel, vulcanite, and such and such lengths of wire are shaped, stretched, and connected with sufficient manual dexterity--for the highest dexterity is very often employed in the making of contrivances which turn out to be futile--but because each of its parts is fashioned in obedience to certain designs with which this dexterity, as such, has nothing at all to do.

The apparatus is successful, and an addition to the world's wealth, because the designs of the inventor, just like the author's manuscript, constitute a multitude of injunctions proceeding from a master-mind, which is not the mind of those by whose hands they are carried into execution.
And with the direction of labour generally, whether in the production of machinery or the use of the machinery in the production of goods for the public, the case is again the same.

We have manual labour of a given kind and quality, which assists in producing what is wanted or not wanted--what is so much wealth or simply so much refuse, in accordance with the manner in which all this labour is directed by faculties specifically different from those exercised by the manual labourers themselves.
And now we are in a position to sum up in a brief and decisive formula what the difference between the sets of faculties thus contrasted is.

It is not essentially a difference between lower and higher, for some forms of labour, such as that of the great painter, may be morally higher than some forms of direction.

The difference is one not of degree, but of kind, and includes two different psycho-physical processes.