Note 248 — Chapter XI · THE ULTIMATE RELATION OF COST TO VALUE

A man may receive part of his income by gift or inheritance and earn a part. The latter part becomes in this case a sort of marginal portion. Though all of his dollars have not cost him disutility, some of them have, and upon principles already discussed, any dollar has the “effective” disutility cost of the most costly dollars. This is just as true as the fact that the first hours of labor may sometimes be play and yet their product always counts as having a disutility cost because of the disutility of the final hour.