One of our priests has been conducting a series of bible studies on the various gospels, which sometimes spills over into sermons and other discussions. I don't know if this is an example of the excessive credulity towards "experts" which a certain type (or lack) of education produces, but he has a certain habit of latching onto anything he reads by "modern biblical scholars" as the latest thing, and then running with it, seemingly without thinking at all about whether or not this might be incompatible with Catholic doctrine. (Father's doctrine is actually quite solid, so this usually just results in a strangely disjoined feeling where he on the one hand relates scholarship suggesting that the authors of the gospels changes or added numerous things in order to make points of their own, while at the same time holding to all the events and doctrines which the disputed episodes convey.)
Anyway, via this exposure to popular biblical scholarship, it's struck me that there's a very different approach that a certain strain of modern biblical scholarship takes to textual evaluation than what I seem to recall from my (admittedly only undergraduate level) time reading classics scholarship.
Biblical scholarship often seems very focused on the idea of stripping away additions and figuring out the original narrative. This makes a certain amount of sense when dealing with a situation where you're trying to discover the facts about a historical occurance based upon the accounts available, but often modern biblical scholars seem to take the approach of assuming that the actual events related by the gospels were primarily or strictly non-miraculous, and thus working from the assumption that references to miracles and to more specific theology must be later additions. One gets the general impression that the original account of each gospel (if, by the scholar's lights, there can even be said to be such a thing) is so distantly burried as to be virtually unknowable.
By contract, most of the notes I was used to seeing in the apparatus criticus were generally fairly matter-of-fact and had to do with relatively minor differences, corruptions and deletions suggested by examination of different manuscripts. Perhaps it's simply that no one imagines that anyone cared enough about changing Horace's Odes or Vergil's Eclogues to have made massive changes in the manuscript tradition, but there was seldom any suggestion that there were many changes after the initial writing of the work, other than accidental ones or subtractive editing.
My impression (perhaps wrong) is that there is not actually more than the usual amount of variation in the surviving manuscript traditions of the gospels, and that there were rather more manuscripts floating around for the gospels than there were for many of the great classical works -- which you would think would provide ample opportunity for variation to show up if it did in fact exist.
All of which leaves me wondering, is there some reason to be running around supposing all these prior narratives and additions and modifications in the gospel narratives, other than general suspicion (on the part of those who are not orthodox Christians) of their contents? Beyond skepticism of the events conveyed, is there a reason to think that Luke's gospel is that much different from what Luke wrote than our extant copies of Heroditus or Thucydites or Virgil are from what those respective authors wrote?