I often joke that my interest in the chronology of the New Testament, especially the dates at which the texts were written, is purely the product of an obsessive-compulsion. While not denying that there is perhaps something vaguely pathological in the pleasure that I derive from such objectively tedious work, the truth is that there is much more to it than that. And for that something more, one must look to this thing that Lonergan calls dialectics.
The term "dialectics" of course has a long pedigree in western thought. But in Lonergan's particular understanding of it, it becomes the study of the conflicts immanent in our lives together as human beings. Writes Lonergan, in Method in Theology: "[t]he materials of dialectic, then, are primarily the conflicts centering in Christian movements. But to these must be added the secondary conflicts in historical accounts and theological interpretations of the movements." And here we have in nuce the question behind the question of New Testament chronology. Actually, the questions because the question. Excluding hypothetical texts such as Q, there are by my count thirty-three extant Christian texts that could arguably be dated to the first century (the twenty-seven canonical texts, plus 1 Clement, the Ascension of Isaiah, the Didache, the Epistle of Barnabas, the Gospel of Thomas, the Shepherd of Hermas). It makes a substantive difference for understanding the conflicts that emerged in the first century whether these texts were written during those first seventy or so years of Christian history, and in what approximate order. That is the first question. But arguably as crucial is the second question, namely the modern conflicts over the matter of when the texts were written.
This second question is best elucidated, as are many things, by appeal to Ferdinand Christian Baur. Back in the mid-19th century, Baur argued that many of the New Testament texts were written at dates that we now know to be impossibly late. We know that now because we have access to information that Baur did not. Indeed, much of that information was generated in response to Baur. But the really interesting story with regard to Baur is not simply that he made empirical judgments that turned out to be false, but rather why he made them. At the risk of oversimplifying (a constant danger with a mind as lively as Baur's), he began with a roughly Hegelian framework of early Christian history, which he then used to evaluate such questions as the dates of the New Testament texts. In other words, he dated John's Gospel to the late-2nd century in large part because that best fit with how he thought early Christianity had to have developed.
Now, of course, no one is immune to preconceptions, prejudices, and the like. But what the example of Baur drives home is the necessity to constantly be moving back and forth between the data and our heuristic anticipations. We anticipate that certain things will be the case in the data. To the extent that the data meets our anticipations, we can judge the anticipations to reasonably apprehend reality. To the extent that they do not, we need to generate new anticipations. My interest in chronology, especially the dates of the New Testament texts, is thus ultimately a way of testing the extent to which the relevant data meets my anticipations about Christian origins. It means querying those anticipations, revising or abandoning them as necessary, affirming them when reasonable. And in carrying out this work I address not only dialectical development in the ancient world, but also in the modern: for our evaluation of Baur's understandings of Christian origins, or of Lightfoot's, or Harnack's, or Robinson's, or Meyer's, or whomever's turns to a remarkable extent upon the degree to which they can be said to have adequately or inadequately apprehended the realities that they studied. Their place in the history of thought about Christianity is not altogether separable from their capacity to think well about Christianity.