Schaeffle considered that government justifies itself in protecting the weaker members of society, and in maintaining the highest welfare of all. He pointed out the social responsibility which rests upon the best educated and most fortunate members of society. Schaeffle wisely emphasized the development of purposeful activity on the part of both the individual and society. The ideas of John Stuart Mackenzie differ from those of Spencer, Lilienfeld, and Schaeffle. Mackenzie does not use the figure of an organic analogy; he speaks in terms of homologies. According to Mackenzie, society is not like an organism; it is organic. The organic nature of society is three-fold. (1) There is an intrinsic relation between the parts of society and the whole. The individual reflects the culture of the group in which he has been trained. (2) The development of a group is by virtue of intrinsic processes. A group builds on ideas derived from both the past and from other groups, but it does not genuinely grow unless it takes these ideas and makes them over into a part of its own nature. (3) Society develops towards ends which are discoverable in society itself. By analysis of the ideals and motive forces of a group, it is possible to determine in what direction the group is moving. Mackenzie argues for the inner principle of things and particularly of society. He believes, however, that knowledge concerning this inner principle and the essential unity of mankind cannot be reduced to a science, but will constitute the basis of a social philosophy. Social philosophy does not supply facts, but seeks to interpret the significance of the special aspects of human life with reference to the social unity of mankind.[XVI-15] The family and the state are the two forms of association in which the most intimate bonds of union are nurtured. Language, if it can be called a social institution, is perhaps the most fundamental institution of all, because it produces that community of spirit whereby intimacy in social intercourse can take place and whereby the realization of a common good can be achieved.[XVI-16] According to Mackenzie, there are three main lines of social progress, and hence three main types of social control to be encouraged.[XVI-17] (1) The control of natural forces by human agencies. (2) The control of individuals by the communal spirit. (3) Self control.