4. _Things are causally related in varying degrees to the psychic income, and have value only as their relation is known and felt._ The explanation of value is not complete till value has been traced back to its source in gratification. Often the complex nature of the problem is ignored. If one discusses the trading of a bushel of grain, to be used by a hungry man for food, for a sheep to be kept for breeding, or for wool to be made into cloth next year, he may overlook the difference in the grade of wants compared. In this case, a gratification of the present moment is compared with a gratification of a very different kind at a future time. The problem involved is complex because of differences in time, in place, and in the nature of the want-gratifiers. The student should endeavor to reduce the problem of value to its simplest form by considering first the exchange, at the present moment, of immediately enjoyable goods. The logical starting-point in the theory of value is in those goods that are in closest touch with feeling, and on this basis may be built up an explanation of values in which reason and forethought have a greater part. Starting from the proposition that psychic income is the foundation of all values, we shall go on, however, to trace causes that give value to all the physical agents, and to the most indirect of want-gratifiers. DIVISION B--WEALTH AND RENT CHAPTER 7 WEALTH AND ITS INDIRECT USES § I. THE GRADES OF RELATION OF INDIRECT GOODS TO GRATIFICATION [Sidenote: Technical rank of agents] 1. _Goods may be ranked according to their technical relation to wants._ The technical rank of goods (sometimes spoken of as the degree of roundaboutness of the process) signifies the number of steps or processes that intervene between the agent used and the desired form. If one wishing the hickory-nut hanging above his head must first pick up a stick to throw at it, the nut is removed one step from desire. But even among savages the processes are much more complicated. The Indian with a crude knife fashions his bow and arrow, fastens the flint and cord which represent still other processes of industry, and shoots the bird which satisfies his hunger. In modern conditions the relations are vastly more complicated; only at the end of a long series do men arrive at the thing which gratifies their wants. [Sidenote: Time relations of goods to wants]