What is "eclecticism?" In simplest terms, it is theprocess of compiling a text from multiple sources. This is incontrast to the notion of editing from a"proof text,"in which one follows a chosen text unless there is an overwhelmingreason to do otherwise.
It is interesting to note that eclecticism is often treatedin classical circles as a bad thing (where many prefer proof text orbest-text editing), but I've never heard of a New Testament editionthat isn't basically eclectic. Even the Byzantine-priority texts,although they follow one text-type, do not follow one particularmanuscript. So, in New Testament circles, the only decision is whichsort of eclecticism to used.
In New Testament criticism, there are basically three approaches:"Thoroughgoing" eclecticism (also known as "radical"eclecticism), "Reasoned" or"Rational" eclecticism (W. W. Greg once referred to thisas "restricted" eclecticism), and "Historical/Documentarycriticism." The first two approaches are always eclectic,compiling a text from multiple sources, and the third, although notinherently eclectic, has (as noted) always been so in practice.
In simplest terms, thoroughgoing eclecticism consists of takingall manuscript readings and choosing the best based solely oninternal criteria. Historical/documentary criticism consists ofchoosing readings based solely on their manuscript attestation,by some means such as preparing a stemmaor counting text-types or justfollowing the best manuscript. Andreasoned eclecticism consists of splitting the difference:Evaluating variants based on both their attestationand their intrinsic merit.
It will be evident that this is actually a continuum: Alleditors are eclectic to some extent, and all use internaland external evidence to a degree. But the extent variesgreatly, and sufficiently that it is reasonable to speak ofthree camps.
Currently, reasoned eclecticism is the dominant forcein New Testament criticism; those who engage in other formsof criticism are a relatively small minority, who can findsome difficulty in having their work respected.
It has not always been so. It is noteworthy that this sortof eclecticism is not considered proper in most areas ofClassical Textual Criticism.In Shakespeare criticism, for instance, the standard methodfor editing is to take a particular proof text (usually theFirst Folio, but sometimes one of the quarto editions), andfollow that except where the evidence of some other sourceis overwhelming. In other words, all modern Shakespearecritics are historical/documentary critics, generally of whatwould in New Testament circles be considered the most extremetype.
And this method has been followed in New Testamentcriticism, though the matter is rarely described in that way.The edition of Westcott and Hort, to a significant degree,is compiled using B as a proof text. Tischendorf's eighthedition is almost as strongly influenced byℵ.Few other editions are so strongly dependent on singlemanuscripts, but there is a lot of D in the Clarketext of Acts, and the recent Majority Text traditionscould almost be treated as being taken from a singleproof text of that text-type.
It should be noted that the three categories of eclecticismdescribed above are not actually methods of editing theNew Testament text. They are, rather, approaches to creating amethod. Historical/Documentary criticism, for instance, says,"determine the relationships between the manuscripts andreconstruct the text based on that." If you determinethat the best manuscripts are the Alexandrian, you get theedition of Westcott & Hort;if you determine the Byzantine are best, you getHodges & Farstad;if you treat all types equally, you'll probably get somethinglike Von Soden.
Similarly, the approach of Thoroughgoing Eclecticism isto "determine the best rules of criticism and determinethe best text based on that." Since editions based onthis principle are very few, we cannot show how differentforms of the method produce different texts -- but it'seasy to imagine the results. Take just one rule, "preferthe shorter reading." Some critics swear by this rule,other reject it almost completely. Suppose there were twoeditors, one of whom considered the shorter reading theprimary evidence of originality while the other consideredthe longer reading universally best. Imagine how differenttheir texts would be!
Reasoned Eclecticism splits the difference, saying,"Determine the relations between the manuscripts and thebest rules of criticism, and proceed from there." As itturns out, most recent editors have agreed, at least in outline,on both the best manuscripts and the best rules, so the moderneditions compiled based on Reasoned Eclecticism (i.e.Bover,Merk, andUBS) are all fairlysimilar. But this is not inherently so; Harry Sturz wouldprobably qualify as a Reasoned Eclectic, but had he edited atext, it probably would not have looked much like Merk orBover -- it would certainly have had more Byzantine readings,and possibly some other surprises.
It is quite difficult to offer examples where all three methodsproduce divergent results, particularly if one uses theWestcott & Hort textas the "standard" for historical-documentarycriticism. If we takeHodges & Farstad asthe standard instead, we have slightly better luck -- thoughstill limited, simply because there are so few places wheredifferent editors adopt three different readings.
One I know of is Matthew 22:7. Here the UBS text reads
ο δε βασιλευςωργισθη
The Kilpatrick edition, the first text to be compiled basedon thoroughgoing eclecticism, reads
ακουσας δε οβασιλευςωργισθη
και ακουσαςο βασιλευςεκεινοςωργισθη
The Kilpatrick reading is supported by 33 (alone or nearly),and is adopted apparently because it best explains the at leastsix different readings in this passage:
ακουσας δεο βασιλευς
και ακουσαςο βασιλευςεκεινος
και ακουσαςεκεινοςο βασιλευς
The UBS editors probably preferred their reading because it is supportedby several good witnesses --ℵ B L1 700 892* 1582 -- and because it could easily have given rise to certainother variant readings, notably the readingο δεβασιλευςακουσαςof Θ 13.
And Hodges and Farstad preferred their reading because it had the bestsupport from the Byzantine manuscripts: E F G (K) Y Π etc.