Here is a teacher giving a music lesson to a class of children. This is a social activity. Within the province of which of the sciences does it fall? Our answer depends upon the point of view from which we regard it. Are we interested in knowing whether or not the teacher's methods of instruction are sound? If so, our scientific study of the activity falls within the field of the science of education. If we desire to know the influence of the music on the mind of the children, our interest is psychological. If, however, we consider the teaching as a means by which the teacher earns her livelihood or as a preparation for the children to earn their livelihood, or as a means by which their desire for music is gratified, our interest is economic, and our study falls within the boundaries of economics, and we speak of the activity as an economic activity. The fact remains that it is more than an economic activity, but for the time being we are interested in it only as an economic activity. But we shall never be able to understand perfectly the activity of the music teacher as an economic phenomenon, unless we understand it also as more than an economic phenomenon. Certain human activities make up the subject matter of economics, but these activities cannot be absolutely separated from the human activities which form the subject matter of other sciences. The difference in the point of view from which we regard the subject matter of the social sciences quite as much as difference in the subject matter itself, distinguishes these sciences from one another.