20 Such, Venerable Brethren, are the characteristics, the aim and conditions of Catholic Action, considered in its most important function, namely, the solution of the social question. For that reason it demands the most energetic attention of all the Catholic forces. By no means, however, does this exclude the existence of other activities nor does it mean that other organizations should not flourish and be promoted, for each one is directed to different particular goods of society and of the people. All are united in the work of restoring Christian civilization under its various aspects. These works, rising out of the zeal of particular persons, spreading throughout many dioceses, are sometimes grouped into federations. Since the end they foster is praiseworthy, the Christian principles they follow solid, and the means they adopt just, they are to be praised and encouraged in every way. At the same time, they must be permitted a certain freedom of organization (since it is impossible for so many people to be formed in the same mold and placed under the same direction). Organization, therefore, must arise spontaneously from the works themselves, otherwise it will only be an ephemeral building of fine architecture, but lacking a solid foundation and therefore quite unstable. Particular characteristics of different people must also be taken into consideration. Different uses, different tendencies are found in different places. It is of primary importance that the work be built on a good foundation of solid principles and maintained with earnestness and constancy. If this is the case, the method used and the form the various works take will be accidental.
Source: Il Fermo Proposito (Vatican.va)