An idolatrous Paganism tended to repress the externals of Christianity, as, at this day, the presence of Protestantism is said to repress, though for another reason, the exhibition of the Roman Catholic religion. On various grounds, then, it is certain that portions of the Church system were held back in primitive times, and of course this fact goes some way to account for that apparent variation and growth of doctrine, which embarrasses us when we would consult history for the true idea of Christianity; yet it is no key to the whole difficulty, as we find it, for obvious reasons:--because the variations continue beyond the time when it is conceivable that the discipline was in force, and because they manifest themselves on a law, not abruptly, but by a visible growth which has persevered up to this time without any sign of its coming to an end.[29:1] 21. The following Essay is directed towards a solution of the difficulty which has been stated,--the difficulty, as far as it exists, which lies in the way of our using in controversy the testimony of our most natural informant concerning the doctrine and worship of Christianity, viz. the history of eighteen hundred years. The view on which it is written has at all times, perhaps, been implicitly adopted by theologians, and, I believe, has recently been illustrated by several distinguished writers of the continent, such as De Maistre and Möhler: viz. that the increase and expansion of the Christian Creed and Ritual, and the variations which have attended the process in the case of individual writers and Churches, are the necessary attendants on any philosophy or polity which takes possession of the intellect and heart, and has had any wide or extended dominion; that, from the nature of the human mind, time is necessary for the full comprehension and perfection of great ideas; and that the highest and most wonderful truths, though communicated to the world once for all by inspired teachers, could not be comprehended all at once by the recipients, but, as being received and transmitted by minds not inspired and through media which were human, have required only the longer time and deeper thought for their full elucidation. This may be called the _Theory of Development of Doctrine_; and, before proceeding to treat of it, one remark may be in place.