Note 40 — Chapter I

The matter may also be put in this way. There are ninety-nine labourers engaged on a certain work at which there is room for a hundred. The ninety-nine men produce every week value to the amount of ninety-nine pounds. There are two candidates for the hundredth place: one a labourer, John; and one, a man of ability, James. If John takes the vacant place, we have a hundred men producing a hundred pounds. If James takes the vacant place, the productivity of labour by his action is (we will say) doubled, and we have a hundred men producing a hundred and ninety-eight pounds. No amount of theory based on the fact that James could do nothing without the ninety-nine labourers can obscure or do away with the practical truth and importance of the fact that the exertion of James will produce ninety-eight pounds more than the exertion of John; and any person with whom the decision rested, which of these two men should take the hundredth place, would base their decision on this fact.