CAUSES OF DOCTRINAL DEVELOPMENT.
5. There is order in all things that exist. This principle holds good for the supernatural mysteries of revelation, as well as the truths that fall naturally within the range of human reason. For any series of objective verities to become subjective truth __ us, that is to say, that they may be adequately apprehended by the intelligence, assimilated to the mind, and recognised by us as true, due order must be observed in their proposition, conception and discussion. What is of a prior order will claim to be proposed, accepted, weighed, analysed, and settled, before what comes after in order. Hence certain truths and principles must appear first in the field, to be worked out in their details, and verified in their results, before others. They will consequently be seen in full development earlier than others. For as in objective truths themselves there is a gradation of ontological order, as also in the subjective process of their intellectual development and of their outward manifestation, there is a subordination [to] logical sequence.
This principle is strikingly exemplified by the history of doctrinal development in the Catholic Church. Thus the controversies and dogmatic definitions, which stand out first and most prominently in the early centuries of Christianity, are such as bear upon the primary truths of the origin and nature of good and evil, Creation, the Nature of God, His Trinity in Unity, the Eternal Godhead and twofold Nature of the Incarnate Word, the Divine Personality of the Holy Ghost, and the grace of Redemption. These primary mysteries were the first to receive explicit development. Many other revealed truths, accessory to the Faith, had long to bide their time for their more full elucidation: and, meanwhile, their teaching remained more or less implicit. Amongst these was the Church's complete doctrinal teaching concerning the Blessed Virgin Mary.
6. But quite apart from this intrinsic principle of order, there were also extrinsic reasons why the first teachers of Christianity had to use reserve in setting forth certain doctrines and practices which, later on, were explicitly taught, and universally sanctioned, by the Church.