Lump of labour fallacy

"The spread-the-work schemes, in brief, rest on the same sort of illusion that we have been considering. The people who support such schemes think only of the employment they would provide for particular persons or groups; they do not stop to consider what their whole effect would be on everybody. The spread-the-work schemes rest also, as we began by pointing out, on the false assumption that there is just a fixed amount of work to be done. There could be no greater fallacy. There is no limit to the amount of work to be done as long as any human need or wish that work could fill remains unsatisfied. In a modern exchange economy, the most work will be done when prices, costs, and wages are in the best relations to each other."