Hence the necessity for the doctrine of Infallibility. For Roman developments are not the only ones. The Eastern Churches have theirs; Protestant Churches have theirs; and outside these there are other developments, both non-Christian and anti-Christian. Unless there is some authority which can say, "Our developments are Divinely inspired and necessary, while all others are superfluous or wrong," the doctrine of Development may be used with as much force against Rome as for her. Consequently, we find the author of the Essay using the theory of Development as an argument for that of the Infallibility. "If the Christian doctrine, as originally taught, admits of true and important developments, ... this is a strong antecedent argument in favour of a provision in the Dispensation for putting a seal of authority upon those developments.... If certain large developments of it are true, they must surely be accredited as true" (pp. 117-19).
This is further proof that what is contemplated in this theory is not mere logical deductions from revealed truth; for logical deductions vindicate themselves by an appeal to the reason, and need no sanction from an infallible authority. Developments are indeed said to follow by way of "logical sequence," but this term is made to receive an enlarged meaning. "It will include any progress of the mind from one judgment to another, as, for instance, _by way of moral fitness_, which may not admit of analysis into premiss and conclusion" (p. 397). Thus the "deification of St. Mary" is a "logical sequence" of our Lord's Divinity. "The votaries of Mary do not exceed the true faith, unless the blasphemers of her Son came up to it. The Church of Rome is not idolatrous, unless Arianism is orthodoxy" (p. 406). The following criticism, therefore, does not seem to be unjust: "However the theory may be modified by the subsequent additional supposition of infallible guidance, it is quite evident that, considered in itself, its internal spirit and scope (especially as illustrated by its alleged Roman instances) are nothing short of this, that _everything_ which _certain_ good men in the Church, or men assumed to be such, can by reasoning _or feeling_ collect from a revealed truth is, by the mere fact of its recognition [_i.e._ by the supposed infallible guide], admissible and authoritative."[112] This is indeed a wide door to open for the reception of additions to the faith!
That St. Jude lays much stress on the fact that the sum total of the Gospel, and not merely the elementary portions of it, have been once for all committed to the Church, is shown, not only by the prominence which he gives to the thought here, but by his repetition of it a few lines later, when he begins the main portion of his Epistle: "I desire to put you in remembrance, though ye know _all things once for all_" (ver. 5). Any teaching of new doctrines is not only unnecessary, it is also utterly inadmissible. And every Christian has his responsibilities in this matter. He is to "contend earnestly" (ἐπαγωνίζεσθαι), with all the energy and watchfulness of an athlete in the arena, for the preservation of this sacred deposit, lest it be lost or corrupted. And the manner in which this earnest contest is to be maintained is not left doubtful; not with the sword, as Beza rightly remarks, nor with intemperate denunciation or indiscriminate severity, but with the mighty influence of a holy life, built upon the foundation of our "most holy faith" (vv. 20-23). It is in this way that lawful development of Christian doctrine is secured; not by additions to what was once for all delivered, but by a deeper and wider comprehension of its inexhaustible contents. "If any man willeth to do His will, he shall know of the doctrine."
NOTE.--In connexion with the subject treated above, chapter ix. of R. H. Hutton's sketch of _Cardinal Newman_ (Methuen & Co., 1891) may be profitably read.