"Since the origin of biblical criticism in the early nineteenth century, critical scholars have attempted to understand the Gospels in the light of Enlightenment assumptions. Taking for granted that the events described in the New Testament could not have occurred in the way they were described ("If miraculous, then unhistorical"), they have sought alternative explanations. In spite of nearly two centuries of the most painstaking effort to sort out the genuine words of Jesus from those allegedly created by the early church, there remains little substantive agreement among critical scholars. Every new generation finds it necessary to reopen the search for the historical Jesus in the light of changing assumptions--hence the novel, if often tendentious, reconstructions of his life that appear in every publisher's new list. As a historian trained in reading classical texts, I find the Gospels, as I do in the work of the classical Greek and Roman historians, promising material for the reconstruction of the events they describe.I find unconvincing, moreover, the view that the words of Jesus and the events of his brief career were radically modified by his followers after his lifetime, resulting in a discontinuity between his teachings and those of early gentile Christianity. The assumption is widespread that the early church played a significant creative role in reshaping the earliest traditions regarding Jesus, with the result that his teachings came very quickly--within a generation--to be distorted, a process by which the "Jesus of history" was transformed into the "Christ of faith." Those who hold this view have little confidence in the ability of the early Christian community to transmit accurately by oral or written tradition authentic memories of Jesus. They see in the Gospels little more than a mass of fragmentary and contradictory traditions. Hence what the New Testament preserves is the faith of the primitive church that has been imposed on the historical Jesus, from which we can recapture by close textual analysis but with considerable difficulty, only fragments of his life and teaching. But why should we doubt the ability of the early church (a small and closely knit community) to preserve over one generation an accurate recollection of the events of Jesus's [sic] life and teachings? The personality of Jesus clearly made a strong impression on his followers, and it is a personality that is everywhere apparent in the Gospels, which are so easily distinguishable from the legendary accounts that grew up later. In fact, it was not until the second century that the mythmaking began, and we see its manifestation in the apocryphal and pseudopigraphical works of that period. Here, as elsewhere in dealing with historical sources, the brevity of time works in the opposite direction: the credibility of the Gospel writers is strengthened by the face that they were under the scrutiny of eyewitnesses." Gary N. Ferngren Medicine and Health Care in Early Christianity p.6-7
I would just add (1) recent studies in orality and oral transmission in diverse a group as Kenneth Bailey, James Dunn, Eddy and Boyd, and Gerhardsson, despite their diversity in approach and some differing conclusions, overall concur and strengthen the point of Ferngren.
(2) Recent studies in how memory works (Eddy and Boyd; and Bauckham) and the eyewitness accounts in the Gospels (esp. Bauckham) would further support Ferngren.
(3) The early collection and acceptance of the four gospels (Hengel, et al) speaks in favor of the accuracy of their accounts. For too long scholars have propped up their suppositions by appealing to the diversity of the earliest schools that created Q, M, L, etc. without considering (a) the level of connectivity between early Christian churches/communities; (b) the overall unity in accounts themselves and (c) the near ubiquitous unity in acceptance of the four gospels in their earliest years of the church.
One of the sad effects of the Bultmanian and post-Bultmanian impact to NT studies is the fragmentary approach taken in Gospels studies that treated the text with a far greater skepticism than the average critical scholar in almost every other field of ancient history. Historical criticism of the NT became an isolated sub-discipline for elite practitioners much in the same way OT studies fragmented itself away from the Ancient Near East. Thus, Biblical scholars of the New Testament and Old Testament were far more radical, skeptical and derogatory towards their sources then comparative disciplines of other fields working in the same timeframes. Even today the tendency of some scholarship has been to move away from rigorous historical disciplines and make Biblical studies the safe haven for every bizarre theory of post-colonial, post-structure, gender-bending hermeneutical hoop-la. Will a more rigorous historical approach, as taken in say classical studies, offer a helpful corrective to whatever moderate insights have been gained in NT studies by advances in literary theory?