NOTE Present and future goods, uses, desires. We may not the following distinctions to be kept in mind throughout our discussion.
Present goods are any goods actually available for choice at the present moment. These comprise not only goods that may be used directly, as immediately enjoyable, but indirect agents if present. Fu ture goods are any goods that will not be available for choice until some future moment.
All ready durative goods contain either present or future uses, or both kinds. The uses contained in goods must be distinguished from the concrete goods themselves, e.g., the house from its use as a shelter, an az from its cutting of the wood. (On this relation between the uses and concrete agents see above, chs. 11 and 12.) A future good when it arrives, may contain uses available at various economic periods. It is not unusual to speak of a choice between present goods and future goods when more exactly one should speak of a choice between present an future uses of goods. As any particular concrete good, as a field, a building, a machine, may be yielding indirect uses of many ranks, and of many degrees of futurity, the time differences involved in this process must be expressed in terms of the uses rather than in terms of the agents.
In every case the choice made is, at the moment when made, a present choice. We have no future desires tho we may have a present fore cast of a future desire. "Future desires" means desires that will be present at some future time. Present desires are all those desires now being weighed in choice. Present desires may be either desires for pres ent uses or for future uses (either in the same or in different goods). A present desire for future uses is but the anticipation of a future desire, tho the two may be of unequal magnitude. It appears therefore that all time-choices are, in the last analysis, reducible to choices between present desires for psychic-incomes occurring at different time-periods.