5. _Man studies and compares the durable goods that give him command over enjoyable goods, and attaches value to them._ Thus energy is found dissipating itself throughout the world in ways useless to man, and in places where it cannot serve his purposes. As man grows in power of control over nature, he seeks to apply these forces in forms and at places he has selected. If he can arm himself with the energies of mine and torrent, he can react with giant strength on the material world. He ceases to accept passively its conditions, and to live on its grudging gifts; he becomes its fashioner, in a sense its creator. His intelligence and his wants are most important factors determining what the form of the physical world about him shall be. But all the efforts of men in the most developed economy cannot make to disappear the differences in the quality of goods and agents. Desirable goods to consume are limited in quantity, and they vary in quality; hence they have value and some higher than others. Likewise, durable material agents and sources of power are limited in number and vary in convenience of location and efficiency. As men seek to gratify their desires, they attach importance to these agents of power. Each is valued for its service or its series of services. When anything is seen to contain a series of uses, it becomes a rent-bearer, and the economic problem of rent arises, one step more complex than the problem of valuing simple consumption goods. CHAPTER 8 THE RENTING CONTRACT § I. NATURE AND DEFINITION OF RENT [Sidenote: Temporary use and permanent possession of agents] 1. _The temporary use of materials and power and their sources is necessary to bring most enjoyable goods into being._ Indirect goods have value solely because they help to get direct goods. The apple-tree is valued because it bears fruit, and the orchard because the trees give promise of yielding a succession of crops for years to come. There are thus two problems of value in connection with durable goods: that of the value of a temporary use for a brief period, as for a year; and that of the value of a thing itself, the use-bearer, for a long series of years or in perpetuity. To explain what fixes the value of the temporary use is the problem of rent; to explain what determines the value of long-continued use or of permanent control and ownership of a use-bearer is the problem of capitalization. [Sidenote: Origin of the term rent]