The widening of the area of shared concerns, and the liberation of a greater diversity of personal capacities which characterize a democracy, are not of course the product of deliberation and conscious effort. On the contrary, they were caused by the development of modes of manufacture and commerce, travel, migration, and intercommunication which flowed from the command of science over natural energy. But after greater individualization on one hand, and a broader community of interest on the other have come into existence, it is a matter of deliberate effort to sustain and extend them. Obviously a society to which stratification into separate classes would be fatal, must see to it that intellectual opportunities are accessible to all on equable and easy terms. A society marked off into classes need he specially attentive only to the education of its ruling elements. A society which is mobile, which is full of channels for the distribution of a change occurring anywhere, must see to it that its members are educated to personal initiative and adaptability. Otherwise, they will be overwhelmed by the changes in which they are caught and whose significance or connections they do not perceive. The result will be a confusion in which a few will appropriate to themselves the results of the blind and externally directed activities of others. 3. The Platonic Educational Philosophy. Subsequent chapters will be devoted to making explicit the implications of the democratic ideas in education. In the remaining portions of this chapter, we shall consider the educational theories which have been evolved in three epochs when the social import of education was especially conspicuous. The first one to be considered is that of Plato. No one could better express than did he the fact that a society is stably organized when each individual is doing that for which he has aptitude by nature in such a way as to be useful to others (or to contribute to the whole to which he belongs); and that it is the business of education to discover these aptitudes and progressively to train them for social use. Much which has been said so far is borrowed from what Plato first consciously taught the world. But conditions which he could not intellectually control led him to restrict these ideas in their application. He never got any conception of the indefinite plurality of activities which may characterize an individual and a social group, and consequently limited his view to a limited number of classes of capacities and of social arrangements. Plato's starting point is that the organization of society depends ultimately upon knowledge of the end of existence. If we do not know its end, we shall be at the mercy of accident and caprice. Unless we know the end, the good, we shall have no criterion for rationally deciding what the possibilities are which should be promoted, nor how social arrangements are to be ordered. We shall have no conception of the proper limits and