Some of the contributing factors to “conversionitis” come from a false view of history.
Many fundamentalists have a skewed narrative, assuming some sort of “great apostasy of the Church” after the death of the last apostle. The true religion was, according to this story, recovered at the time of the Reformation. The presupposition here is that what “really counts” is a correct systematic formulation or perhaps purity of morals among the Church’s ministers.
RC and EO traditionalists have their own narrative, of course. They presuppose that there has been a drastic falling away at some point in history, but the first five to eight centuries (depending on who you are talking to) indeed represent the apostolic Church. The assumption of correct systematic formulation is about the same as the first group.
Liberals also tell their story. They find discontinuity all around, and thus they assume that there is no united Church, or at least no such thing as “orthodoxy.” Again, the assumption of correct systematic formulation is retained, only its absence serves as conclusive proof.
All of these historical narratives are false. The real story is much more complicated, including lines of continuity and discontinuity on all sides. As Rowan Williams’ wonderful book on Arius shows, lines of continuity from the earlier dogmatics can be traced through both Arius and Athanasius (and of course, lines of discontinuity can be traced through both). The Middle Ages are more complicated, and at the time of the Reformation there is great discontinuity to be found at the Council of Trent and great continuity to be found among the various Reformation movements. And of course, vice versa is true at points as well.
Luther is a child of Valla and Erasmus. Calvin is enamored with Bernard and Bonaventura. John Preston reads Aquinas at the barber shop. Davenant leans heavily on Prosper. Richard Field borrows from Ockam, Gerson, as well as Nicolas of Cusa. We could add the names of Anselm, Dante, Marsilius, John of Salisbury, Wycliffe, Bradwardine, Gregory of Rhimini, and even William the Conqueror, Frederick Barbarossa, and Roger of Sicily to our list of significant names. As Philip Schaff said, “If Protestantism be not derived by true and legitimate succession from the church life of the Middle Ages, it will be found perfectly vain to think of connecting it genealogically with the life of the church at any earlier point” (The Principle of Protestantism 48).
And so it should not surprise us that in the wake of Van Til and Schaeffer’s cultural critiques, and the historical narratives which accompanied them, that our modern Reformed thinkers don’t know where we came from. If we read history looking for “the Reformed worldview,” we will be sorely disappointed, and I’m afraid this is why we’ve given our church history over to Banner of Truth and Soli Deo Gloria. The individual books published by these houses are often quite good (I am routinely impressed by what I find in their pages.), but the overall “team” mentality produced by them is counter-productive. Some graduates step it up to Turretin, but even there, they are not out of danger if they do not also notice the authenticity of the various “Hypothetical Universalists” or “moderate” Reformed churchmen of whom Turretin is typically opposed. Late 17th century French Reformed writer, John Durel, notes that shortly after its completion, the Westminster Confession was denied inclusion in a Genevan collection of Reformed Confessions. The 39 Articles seemed to have a more sound basis among the Reformed tradition at the time. (My how things change!)
A mature Protestant (there are many) remains calm among the storm of history. Messiness is his ally. He knows that history is not a collection of ideas. History is a collection of people.
A good friend of mine told me that the traditional text books are usually right. He was referring to history books that he was assigned in undergrad. I think this is correct. My Western Civ. textbook is about as good a defense of Protestantism as I can think of, and I believe the author is likely a Marxist. It is no real matter though, since he dislikes Protestants as much as Romanists.
If you want a good look at the Patristic era, check out Jewish research and perhaps the liberal Roman Catholics. They are usually very honest. If you want to learn about Eastern Orthodoxy, don’t read a convert! Read someone whose parents actually spoke Greek. And if you see more than two citations of Heidegger, make a run for it!
Bavinck, Delitzsch, even Dabney- these are good guys. They cast wide nets, and are sure to include the political and cultural advances that accompany eras of theology and the Church. Heiko Oberman is great. For living authors, see Charles Taylor, Richard Muller, Oliver O’Donovan, Randall Zachman, and many more. It doesn’t have to be published by an Ivy League press, but that doesn’t hurt! What you want is reality. Church controversies are always about politics, technology, rhetoric, and yes, even exegesis. But of course, exegesis is often effected by tools, assumptions, translations, and motivations. These all matter. Christian character matters as well. Do you believe that the particular writer is a kind and pious soul? For true divinity, he must be.
And above all, Lewis. Read him. Love him.