Does the truth change? Does the eternal truth of Christ change? On one hand believers of all creeds will find the notion of truth changing to be anathema! How can the words of scripture, those spoken by Christ, provide foundation for theological doctrines that change over time? Many scholars will point out good evidence that Abraham believed in many gods, that the early apostles did not believe in the Trinity, and challenge a variety of other Christian truths. Using this as evidence of Christian “advancement” in theology, scholars will use these arguments as data to support the Church changing to be more in line with the views of justice we hold today.
If doctrine develops over the centuries, who is to say it cannot develop to have women priests or allow contraception?
This argument is a powerful one, and I find it assumed implicitly and explicitly by many Christians I will argue with today. However it finds its power in confusion and a lack of defined theory of doctrinal development by traditionalist Christians. This is not to say that such theory does not exist, but that it is little known. In this article and the following piece, I intend to break down and explain John Henry Newman’s theory of how doctrine develops without changing the truth value of claims from Abraham to the Council of Trent. Part I will consist in clearly defining doctrine, authority, and private judgement, which will be pivotal in understanding the actual theory presented in part II.
Newman’s theory of doctrinal development has been a subject of debate among scholars, theologians, and others within and outside the Catholic Church. The Church is divided between those who hold the importance of the role of private judgement as the primary tool of development of doctrine and those who believe Newman was influenced by those who emphasized the importance of authority, rooted in history, in doctrine. This tug of war between tradition and private judgement exists in the Church today.
Before continuing into the thesis, we must clearly establish Newman’s understanding of true authority. When Newman was drafting an essay on his theory of development, he clearly presented his theory as justification for his conversion to Catholicism. Fredrick Borsch, in his writing on the early Oxford movement, argues that the apostolic claims of Christianity grew more important to Newman in his late Anglican years as he grew closer to Catholicism.  Signs of a Church’s saintliness and holiness became of greater concern for Newman as his theory of the development of doctrine demanded authority by which the complexity of theological issues could be properly navigated. Borsch goes on to argue that Newman sought out a sharp harmony between the truths within Christianity, the truths apparent in the reality of the physical world, and the authority of a historic Church.  Newman roots the viability of Christian doctrine in the historical truth being preserved by the Church. The authority of the Church is foundational to Newman in how he looks at the function of authority and private judgement in his understanding of doctrinal development. 
Authority forms the basis for doctrine to have its truth value; without the support of tradition and continuity from the time of Christ, all doctrines will fail. For Newman, doctrine originates in the impression of a Revelation of the divine on the mind of the recipient of the Revelation. After the initial encounter, the recipient reflects upon the Revelation and later develops doctrine out of this private judgement. Newman writes that “theological dogmas are propositions expressive of the judgments which the mind forms, or the impressions which it receives of Revealed Truth.”  Thus, centuries can pass without a new codified doctrine, but the basic essence of that doctrine survives and prospers “secretly” in the faithful Christians who encountered the divine in some manner.  The Church functions as an instrument by which these “secret” beliefs are navigated. Since the necessary authority must be trusted to reliably bear truth, the doctrine of the infallibility of the Church is a necessary component of Newman’s theology.
Protestants and scholars often criticize that infallibility reduced Christianity to a sort of religious absolutism that ignores reflection and private judgement in the name of the pursuit of truth by high ranking theologians. John R. Connolly effectively responds to this criticism by arguing that Newman did not think infallibility would limit reflection, but would act as a tool that would balance authority with private judgement. Infallibility will mitigate the extent to which the opinion of the Church would move in whatever direction the wind of the times was blowing while still allowing private judgement a path, slowly and over an extended period, to become doctrine. 
Next it is important to define what Newman means by “private judgement.” What Newman refers to as private judgement others refer to as conscience, intellectual abstraction, or reflection of the mind, though they all approach the same basic idea. Newman espouses that Revealed Truth makes a certain impression upon the observer, “and this impression spontaneously, or even necessarily becomes the subject of reflection on the part of the mind itself, which proceeds to investigate it, and to draw it forth in successive and distinct sentences.” 
The final stage of the creation of distinct sentences is what we call doctrine. In his book Newman’s Approach to Knowledge, Laurence Richardson argues that Newman defined private judgement as the way in which our mind creates an intellectual abstraction of a sensory experience of some external reality. Therefore, Richardson goes on to say, private judgement is personal and varies from individual to individual. Private judgement corresponds to the impression of an external object, and the closer private judgement corresponds to reality the closer it comes to doctrine.  The initial impression of a divine truth, or any truth, must be subject to private judgement for that truth to be made into concrete sentences that express definitive claims. From these claims established by private judgement, doctrine is founded.
My next article addresses how doctrine “develops” without undermining older doctrines held for centuries.
 This point is made clear in the introduction to: John Henry Newman. An Essay on the Development of Christian Doctrine.
 Borsch, Frederick. Ye Shall be Holy: Reflections on the Spirituality of the Early Years of the Oxford Movement. Pg 357-358.
 Shea, C. Michael. The Role of Newman’s Theory of the Development of Christian Doctrine in the Events Leading to the Definition of Papal Infallibility at the First Vatican Council. Pg 82-83.
 Newman, John Henry. Fifteen Sermons Preached before the University of Oxford. Pg 320.
 Newman, John Henry. Ibid, Pg 323, paraphrased. It should be noted that secretly simply means the doctrine hasn’t been codified but is lived out.
 Connolly, John R., John Henry Newman: A View of Catholic Faith for the New Millennium. Pg 109.
 Newman, John Henry. Ibid. Pg 320.
 Richardson, Laurence. Newman’s Approach to Knowledge. Pg 52.