Still more important is the cultivation of special abilities, impossible without exchange. The indefinitely varied powers of human nature are made most useful where each can devote his talent to a definite business; and usually the talent best fitted to a business is attracted toward it. Habits, too, which are the chief labor-saving characteristics in human nature; become all-important, and enable an individual to do a large part of his work with the least possible care. The routine of everyday life is followed with little effort or pain. The more regular the routine the easier it is to follow.
A still greater advantage to communities is found in the enlargement of the range of wants in all individuals. The superiority of enlightened men over savages is largely due to their greatly increased needs, since necessity, the mother of invention, compels exertion and finds the way to satisfaction. It seems, however, that exchange contributes most extensively to welfare by combining individuals into a community, and smaller communities into a larger, until the whole world is brought into sympathy. Thus every human being gains the advantage of growth in mind and character through some contact with every other human being within the commercial world. If ever a reign of peace and plenty shall extend over the world, no one doubts the importance of commerce and intimate exchange in bringing that time. The full advantage of free exchange in promoting human welfare cannot be over-estimated.
_Exchange limited by powers._--With all its advantages, there are certain obstacles in the way of its extension, always more or less effective in limiting its range. A community can have few exchanges among individuals if all are busied in the same or similar trades. A farming community has little need of buying and selling among the farmers. A horse trade or an exchange of one brute for another may supply all necessities. In larger communities similar limitations are found where abilities are similar, or where habits in education, government or religion are very uniform. In such cases opportunities for exchange are limited, and commerce itself grows slowly.
The story of pioneer settlements is uniformly one of slow and uncertain commerce for want of the variety in wants and abilities which makes the very foundation of exchange. Sometimes "day's work for day's work" is the limit of exchange throughout a whole region or country. In the world at large limitations often arise from hostile feelings between nations, and as yet the highest freedom of exchange between people under different governments has seldom been reached. The United States affords the brightest example of people with varied characteristics developed through the stimulating effect of ready exchange.