Production results from the co-operation of these three equally necessary elements, which, taken separately, are equally sterile.
Political economy, indeed, treats of the production, distribution, and consumption of wealth or values.

But of what values?
Of the values produced by human industry; that is, of the changes made in matter by man, that he may appropriate it to his own use, and not at all of Nature's spontaneous productions.

Man's labor consists in a simple laying on of hands.

When he has taken that trouble, he has produced a value.

Until then, the salt of the sea, the water of the springs, the grass of the fields, and the trees of the forests are to him as if they were not.