Dr. Carroll has made some cogent, insightful statements at the beginning of the first volume mentioned above (pp. 11-12), about method and bias. I agree wholeheartedly:
The majority of the citations in these notes refer to secondary sources – that is, to the work of modern historians on which the author has drawn. Primary sources - documents contemporary with the period under review - are used from time to time, particularly where there is a strongly controverted point, but comprise only a minority of the citations. This is simply because of the scope of this work, which renders it impossible for any one man in a reasonable period of time to master all or most of the applicable primary sources adequately; even if this were possible, it would not be a reasonable expenditure of time and effort, since so many painstaking and conscientious scholars have already investigated the primary sources with the utmost care and have reported thoroughly on them. The overriding need is not for more monographs on original sources, but for synthesis from the Christian point of view, in a time when this kind of history has virtually ceased being written.
. . . Regarding objectivity, every professional historian knows that the most difficult single task in historical research is pruning down and weeding out the original indigestible mass of raw material into the basis for a coherent presentation of the subject being researched and written about. Every historian must use principles of selection of what material is important and relevant to his general and particular task. Every historian (though not all are fully aware of this) has a world-view which has much to do with his choice of what is significant and relevant. For the historian to suppress evidence bearing directly on his own subject and conclusions is a grave dereliction; but for him to screen out irrelevant information is a duty, an essential part of his craft. In all honesty, every historian owes to his reader an identification and a statement of his own world-view.
Above all it is necessary to see the fundamental error in the widely held idea that the history of religion is "objective" when written by those who do not believe in the religion they are writing about (or often, in any religion) but biased when written by a religious man. The rejection of some or all religious truth is every bit as much of an intellectual position as is the acceptance of religious truth. Both the believer and the non-believer have a point of view. Both are equally tempted to bias; either may be objective by overcoming that temptation. Objectivity does not derive from having no point of view. History cannot be written without one. Objectivity does require honesty and respect for truth always.
This is how I try to approach my own apologetic research, particularly when I write from an amateur historiographical apologetic viewpoint. I especially appreciate Dr. Carroll's remarks about secondary sources, since I have argued the same thing for years from my non-scholar's viewpoint: I'm an apologist; pure and simple. It would be folly and presumption for me to pretend to be a scholar, let alone an historian. Therefore, it is perfectly proper and well and good that I cite the work of professional historians about historical matters. I don't have to be acquainted with every primary source every time I cite someone like Luther or Jonathan Edwards or Charlemagne or whomever it may be (some folks seem to think this is strictly necessary, lest I be guilty of gross misrepresentation and incompetent research). As Dr. Carroll notes, even historians are not strictly obliged to do so, since he himself has consciously relied mostly on secondary sources for his purposes, even in a major, multi-volume history of Christianity.
It's also good that theologically-liberal and dissident historians are also increasingly willing to make their biases known, so that readers are not left guessing. For example, the well-known proclaimed "Catholic" historian Brian Tierney, author of scholarly works such as Origins of Papal Infallibility, 1150-1350: A Study on the Concepts of Infallibility, Sovereignty and Tradition in the Middle Ages, and Rights, Laws and Infallibility in Medieval Thought, makes no bones about his disbelief in the subject he writes about. Here is a portion from the Introduction (pp. 2-5) of his book, Origins of Papal Infallibility: 1150-1350 (Leiden: 1972; emphases in green added):
If the popes have always been infallible in any meaningful sense of the word—if their official pronouncements as heads of the church on matters of faith and morals have always been unerring and so irreformable - then all kinds of dubious consequences ensue. Most obviously, twentieth century popes would be bound by a whole array of past papal decrees reflecting the responses of the Roman church to the religious and moral problems of former ages. As Acton put it, "The responsibility for the acts of the buried and repented past would come back at once and for ever." To defend religious liberty would be "insane" and to persecute heretics commendable. Judicial torture would be licit and the taking of interest on loans a mortal sin. The pope would rule by divine right "not only the universal church but the whole world." Unbaptized babies would be punished in Hell for all eternity. Maybe the sun would still be going round the earth.There is much to be said for transparent honesty, isn't there? Tierney must be admired for having no reluctance whatsoever to reveal his glaring heterodox Catholic affinities. He has "grown" far more than, say, Dan Rather, who never quite managed to admit that he was a far left political liberal; hence prone to the most outrageous bias (such as - to pick an example out of the blue - his reporting on President Bush and his earlier days during the last election campaign). Heads rolled at CBS, but Rather's was never one of them (despite the disdain even of the veteran reporter Mike Wallace). Not so, Tierney, or folks like Hans Kung. We know where they stand!
All this is impossible of course. No one understands the fact better than modern theologians of infallibility. If past popes have always been infallible — again, we must add, in any meaningful sense of the word—then present popes are hopelessly circumscribed in their approaches to all the really urgent moral problems of the twentieth century, problems involving war, sex, scientific progress, state power, social obligations, and individual liberties. The existence of this dilemma helps to explain the rather eccentric development of the doctrine of infallibility during the past century. Since Vatican Council I, Catholic theologians have felt obliged to defend some form of papal infallibility. Real infallibility has regrettable implications. In the years since 1870, therefore, theologians have devoted much ingenuity to devising a sort of pseudo-infallibility for the pope, a kind of Pickwickian infallibility.
Their usual technique has been to raise endless, teasing, really unanswerable questions about the meaning of the term ex cathedra as used in the decree of Vatican Council I and about the phrases "ordinary magisterium" and "extraordinary magisterium" that came to be associated with it in discussions on papal infallibility. Already in 1874 Gladstone could write, "... There is no established or accepted definition of the phrase ex cathedra and (the Catholic) has no power to obtain one, and no guide to direct him in his choice among some twelve theories on the subject, which, it is said, are bandied to and fro among Roman theologians, except the despised and discarded agency of his private judgment."
. . . The one consistent rule of interpretation we can be sure of encountering is this: whenever a theologian disagrees with some old teaching or new ruling of a pope he will find good theological grounds for deciding that the papal pronouncement was "not infallible." The whole modern doctrine of infallibility in its Pickwickian form might be summed up in the general principle, "All infallible decrees are certainly true but no decrees are certainly infallible."
. . . the pronouncements of popes, even of modern popes, sometimes contradict one another (notably, for example, in the matter of religious toleration). Some theologians therefore have upheld the infallibility of contemporary decrees without giving serious consideration to the possibility of their conflicting with preceding ones. In effect, they are content to pretend that the past did not happen. There is at least a beguiling innocence in this approach. Other theologians, more reprehensibly (from a historian's point of view), have devised hermeneutical principles so ingenious that the documents of the past can never embarrass them. By applying such principles, they can reinterpret any doctrinal pronouncement, regardless of its actual content, to mean whatever the modern theologian thinks that its framers ought to have meant. [footnote: A good introduction to the hermeneutical problems that arise when theologians try to reconcile doctrinal statements from different ages of the church's past that are really irreconcilable with each other is provided by H. Riedlinger, "Hermeneutische Ueberlegungen zu den Konstanzer Dekreten" is Das Konzil von Konstanz, ed. A. Franzen and W. Müller (Freiburg, 1964), pp. 214-238.] The infallible doctrine of the past remains infallible but it is deprived of all objective content. This procedure seems based on a kind of Alice-in-Wonderland logic. One is reminded of the Cheshire Cat—the body of a past pronouncement disappears but its grin of infallibility persists. The general principle underlying this second major approach to the problem of infallibility might be summarized in the formula, "All infallible pronouncements are irreformable—until it becomes convenient to change them." It seems only fair to add that most Catholic theologians have continued to opt for some version of the relatively simple and straightforward Pickwickian position.
By the time of Vatican Council II the Catholic theology of infallibility had become a tangle of paradoxes and evasions. The theologians had worked themselves into a complicated cul-de-sac. But the council refrained from any thorough-going reconsideration of this question and merely repeated with minor variations the doctrine of 1870. In the years since Vatican Council II, however, a new development of thought has occurred. Very recently—while this book was being written—a few Catholic scholars have begun overtly to challenge the validity of the doctrine that was defined at Vatican Council I and reaffirmed at Vatican Council II. [footnote: F. Simons, Infallibility and the Evidence (Springfield, Ill., 1968); F. Oakley, Council Over Pope? (New York, 1969); H. Küng, Unfehlbar? Eine Anfrage [Infallibility?: An Inquiry] (Zurich, 1970).] It remains to be seen whether their point of view will establish itself as a viable position that can be held within the Roman Catholic church.
Let's all be thankful for small favors . . .
For further related reading:
Brian Tierney: Inveterate Enemy of Papal "Tyranny" and Infallibility
The Modernist, Secularist Historicism of Raymond Brown and Brian Tierney (including lengthy citations from St. Thomas Aquinas on papal infallibility, Joseph Cardinal Ratzinger, Msgr. George A. Kelly, and Protestants J. Gresham Machen and Os Guinness on Liberalism)
The Historical Credibility of Hans Kung (Joseph Costanzo)
Christian Apologetics and Academic Historiography: Similarities and Differences (vs. Edwin Tait)
Discussion on Orthodox Caesaropapism & Proper Historiography (vs. "Theophan" & Joel Kalvesmaki)
A Defense of Amateur Apologetics a la C.S. Lewis and G.K. Chesterton
Martin Luther the "Super-Pope" and de facto Infallibility: Extensive Documentation From Luther's Own Words and a Discussion of Protestant Charges Concerning Alleged Widespread Dishonesty of Catholic Apologists in Dealing With Luther
Protestant Contra-Catholic Revisionist History: Pope St. Pius X and Cardinal Newman's Alleged "Modernism", Version II (vs. David T. King)
Catholic Historiography: Brian Tierney and John Henry Newman
Was Conciliarist Ecclesiological Theory an "Orthodox" Option in Mediæval Catholicism?