But the interchange of ideas on social life has led to an increase of ideals, which are plans of action emotionally appreciated and therefore motive forces. Some of these are the Utopias of individual thinkers; but we shall consider here only those more powerful ideals which are shared, however vaguely, by many. In this case also, as in the purely intellectual sphere, the fire spreads from group to group, from nation to nation; and as the interchange of ideas increases knowledge, so the exchange of enthusiasm makes action more powerful. A really effective ideal, however, cannot arise except from the perception of definite evil. Vague discontents may cause such revolution as leads to reaction; but the clear sight of evil is the only source of reform. We may take it for granted, then, that although an ideal is nerveless if it is not passionate, it is futile unless it is based on knowledge. Therefore a hint must be given of the evils from the knowledge of which ideals of social reform now rise. That all is not well in the relations of man to man or of group to group must be fairly obvious to any one with imagination enough for sympathy. General dissatisfaction and universal cures for society are childish; but the perception of this and that evil gives rise to different plans for reform which all originate in the enthusiasm which is an ideal. We may put aside the long history of the growth of this shared enthusiasm for better relations between men, whatever their ability, their rank, their race, or their government. The common ideals of the present are the result of a gradual development, but we shall consider them here as attempts to deal with existing evils and plans for a better future. * * * * *