2. To call the teacher's work unproductive, and the ditch-digger's work productive was once usual, but is so no longer; give reasons for either view.
3. It is usual to call the use of a house for business purposes a productive use, but its use as a residence an unproductive one. What reasons are there for and against this?
4. Give a list of material agents that are yielding non-material uses.
5. Give examples of personal services that are most immediately expressed as gratifications.
Note.—The phrase "psychic income," used here for the first time, expresses a conception long neglected, but essential to the advancement of psychological economics. The idea has been recognized in the writings of Edwin Cannan, Irving Fisher, W. M. Daniels, and perhaps of late by others. It was discussed by the author in the Quarterly Journal of Economics, Vol. XV, pp. 19-30, especially pp. 25-26, in an article called "Recent Discussion of the Capital Concept" (November, 1900).
Chapter 7. Wealth and its Indirect Uses
1. Give reasons for attributing exchange value to the waves of the ocean; to a waterfall, a water-wheel, a loom, a piece of cloth, a dress made of the cloth.
2. Show the connection between these things.
3. How can the use of a flock of sheep be of value to one who must return them all to the owner?
4. Why should the use of a machine that never can be a direct cause of gratification, have a value that men will pay for?