CAUSES OF DOCTRINAL DEVELOPMENT.
4. We should bear in mind that Christianity is now some abstract philosophy, the truth of which may be passively accepted by a merely intellectual assent; but that its doctrines -- even those accounted the more speculative -- become, when appropriated by the mind and heart, principles of moral energy, and a vital force, which entering into all manner of human action have power to influence man's will and direct his conduct, not only personally as an individual, but also in all his relations, domestic, social, and political.* The Christian religion is, moreover, intended for the whole world, to be universal as to place and time, and is hence capable of application to all mankind under every variety of circumstance and condition, whether of age, country, or civilisation; and this variety is to go on increasing and multiplying until the end of time. Hence Christianity will, in a manner, appear outwardly diverse, as it is viewed under different aspects, and seen clothed with various accidental forms. But, in truth, "it changes with them in order to remain the same." Whatever change there may be, is not of Christianity itself, but one of appearance only, through the application of its original doctrines and principles to new cases. Development here there is, but it is not accretive.
We might, indeed, allow that there is here an accretive development in such sense, that the fresh cases and new circumstances for application must first achieve their actual existence, and be brought into direct contact with the doctrines and principles of Christianity, before these can be really operative, and attain their natural result. In order to test the force and extension of any great principle -- that it may have fair play, and show its normal development -- it must have an adequate sphere for its operation, together with such events and circumstances in the passage of time as shall call it into proper action, and duly test its power. Thus the Primacy conferred by Christ upon S. Peter and his successors was unable to attain its normal exercise, nor could the fulness and extent of its power be adequately gauged and verified in the life-time of the prince of the Apostles, or under the Popes during the age of persecution. To show itself normally, and in full development, it needed for its exercise a field of operation in some way proportioned to its universal jurisdiction, where it might bear influence on the world at large, and measure its supernatural force with human opposition of every kind, whether arising from the jealousy of secular Christian princes, the rivalry of ambitious prelates, the wily deceits of heresy and false philosophy, or the resistance of disobedient Catholics.
* See Newman'sDevelopment, pp. 36, 40: "Doctrines expand variously according to the mind, individual or social into which they are received; and the peculiarities of the recipient are the regulating power, the law, the organisation, or, as it may be called, the form of their development. The life of doctrines may be said to consist in the law or principle which they embody" (p. 178).