Moreover, with the growth of the modern state, with the interest increasing importance of business, and of industrial and commercial interests, as compared with changes of dynasty or the personal rivalries of rulers, economic questions have grown in relative importance. In our own country, particularly since the subjects of slavery and of States' rights ceased to absorb the attention of our people, economic questions have pushed rapidly into the foreground. Indeed, it has of late been more clearly seen that many of the older political questions, such as the American Revolution and slavery, formerly discussed almost entirely in their political and constitutional aspects, were at bottom questions of economic rivalry and of economic welfare. The remarkable increase in the attention given to this study in colleges and universities in the last twenty years is but the index of the greatly increased interest and attention felt in it by citizens generally. To sum up, it may be said that in the study of political economy we are seeking the reason, connection, and relations in the great multitude of acts arising out of the dependence of desires on the world of things and men. CHAPTER 2 ECONOMIC MOTIVES § I. MATERIAL WANTS, THE PRIMARY ECONOMIC MOTIVES [Sidenote: Feeling urges to economic actions] 1. _A logical explanation of industry must begin with a discussion of the nature of wants, for the purpose of industry is to gratify wants._ An economic want may be defined as a feeling of incompleteness, because of the lack of a part of the outer world or of some change in it. Often the question asked when one first sees a moving trolley car or automobile or bicycle is: What makes it go? The first question to ask in the part of the study of economic society here undertaken is: What is its motive force? Without an answer to that question one cannot hope to understand the ceaseless and varied activities of men occupied in the making of a living. The question merits long and careful study, but the general answer is so simple that it seems almost self-evident: The motive force in economics is found in the feelings of men. It is men's desire to make use of men and things about them which calls forth all the manifold phenomena studied in economics. [Sidenote: Animal species shaped by their environment]