On the whole it would seem that in a greater number of cases it is more easily possible to retain a surplus of present goods for future use, than to hasten a future (unripe, un finished, or merely potential) supply, to meet present uses. It would seem that present value is more often, and in the ease of more kinds of goods, and in a greater degree, raised by a chance shortage than it is unexpectedly reduced by a chance surplus.. For usually the surplus can be kept as is often the case even with direct consumptive goods (such as grain, coal, textiles, carriages, etc.), and still more often the case with indirect durative agents, such as tools, machinery, buildings, stocks of metal, etc.
§ 9. Physical-change accompanying time-change. Some goods deteriorate physically by keeping, as fruit rotting in the bins; some remain almost unchanged for a long time, tho costing trouble and expense to store and care for, as cotton, grain, and fireworks. Still others improve physically with time, as newly brewed beer, newly vinted wine, bananas ripen ing on the stem, celery blanching in the cellar, fattening poultry, half ripe fruit on the tree, the violin seasoning and growing richer in tone.
It is difficult in studying the problem of valuation in such cases to keep clearly distinct the two ideas, that of the phys ical change that goes on, and that of the pure time-value change. When the object physically improves with time and at the same time increases in value, the physical change seems to account for the increase; but as great an improvement physically may in other cases be accompanied by a fall in •value. It is evident that no change in value is to be at tributed solely to objective changes in the good, without re gard to complex conditions in the desires of men.
In all such cases and in so far as there is any conscious com parison whatever, it is the net desirability (net present value) of the future goods that is compared with the value of the present goods. If half of the apples probably will rot before it will be time to use them, the present value of the future apples, per bushel, must be somewhat more than twice as great as present apples to make a motive for keeping them, and further allowance must be made for trouble, expense, etc.
But, as a part of the present apples are expected to spoil, they represent, and must be compared with, a smaller number of apples in the future. The physical change is an inevitable (or a practical) condition, of the time change. It is, so to speak, a function of time. It happens rarely, perhaps, that it is with respect solely to time, in simple, unadulterated form, that time-choice, time-preference, and time-value are pre sented to us. Time-value is the present value-difference be tween the possible uses of a thing or group of things at dif ferent times. If therefore the lapse of time is accompanied by increase or decrease of quantity, or by gain or loss in quality, this enters into choice at the present moment .° Undoubtedly, the importance of time in many acts of busi ness life is well understood. "Time is money," is a business maxim. But neither in business nor in the philosophical study of value has the omnipresence of the time element been fully This chapter has, perhaps, served to show how time is a factor in practically all economic choice and in prac tically all valuation. Indeed, time-value and time-preference I have aspects that transcend economics; they are universal phenomena of life and conduct.
We have now to see in the next chapter how time-prefer ence is expressed in the values of goods and how in these valuations necessarily a rate of preference, a premium for time, comes to be expressed in each person's valuations.
8 Each of the four types of value is presented in manifold com binations with the other three. Time-preference is interwoven in the choice of things with relation to place, stuff, form. Time-value as a matter of analysis may be deemed to be added (algebraically either as plus or minus) to the other values in determining the sum of value in a good.