In the illustration we have been considering, it will be observed, there is an extensive schedule of present uses which the new project calls in question and from which the means must be diverted. This is in fact the commoner case. A new use of money will affect, as a rule, not simply a single present mode of expenditure, but will very probably involve a readjustment throughout the whole schedule of expenditure which our separate past valuations of money have in effect co-operated in establishing. So likewise if we wish to use part of a store of building materials or of food, or of any other subdivisible commodity, we encounter an ordered system of consumption rather than a single predetermined use which we have not yet enjoyed. Where this is the case the whole process of valuation is greatly facilitated, but this is not essential. The means in cases of true economic valuation may be capable of but a single use, like a railroad ticket or a perishable piece of fruit, or of a virtually endless series of uses, like a painting or a literary masterpiece. Whether the means figure as representing but a single use or stand for the conservation of an extensive system, their economic significance is the same. They are the "energy-equivalent" of this use or system of uses considered as an act or system of acts of consumption in furtherance of the self. Their past assignment meant then and means now simply this, that the "energetic" self would thereby gain more than it would lose through the inevitable sacrifices. This is the economic significance of the means in virtue of which they are now problematic to the extent of checking, for a time at least, forward tendency toward the desired end.[146]