I recently saw a study regarding what children will believe. In short, different children were told a story about a monster in a box, shown that the box was empty, and told that the story was pretend. When left to their own devices, most acted as if there was indeed a monster in the box. The results were deemed very sobering, and perhaps even disturbing. It seems to me the adults made believing in the monster much more fun than rejecting it. My children certainly behave similarly, and in fact my boy will correct me with "No, we're pretending!" if I stumble into the middle of their conversations. The paradoxes of belief do not end with childhood, and it is just as well. I have no zeal for a world populated only by analytical skeptics, not to mention the inherent hypocrisy of the idea, given the necessity of adopting a null position. Believing nothing at all is tricky business. Of course, the idea of belief as distinct from reason has deep roots in Western philosophy, and is perhaps given most succinctly by Tertullian in the modified aphorism "I believe because it is absurd." Now that's living! Although there are various threads of rationalism running through the medieval era, one can perceive the anti-rationalist element as well, especially with regard to the correlative thinking so prevalent. Since the anti-rationalist generally spurns disputation, the thread is simply less sharp in outline.
Nowhere is the core idea of credibility cast in such relief as on the Internet. What statements do people accept and why? I admit to an almost perverse fascination with arguing in ways differing from the standard form of academic thesis, both because I find the artistic aspect stimulating (cf. Borges) and because I want credibility only for the "right" reasons. The Internet has become my crucible for an exploration of credibility, and so I observe that the trappings with which I present myself have a radical impact on the acceptance of the same argument, or that people will readily believe someone almost entirely ignorant of a subject because he might seem "more like them." Internet people are funny, because they often will not consult even basic reference books for themselves, preferring instead some odd sense of democracy, one which can easily be trumped by dramatic professional introductions but not by statements to the same effect later in a more personal conversation. In short, it is the perfect world of marketing, which is also the world in which music-as-art must ultimately make itself. Unfortunately, for the audience "marketing credibility" can easily conflict with artistic credibility, and the latter is only painfully regained.
It is of course against ideas of "scientific inquiry" and falsifiability which performance-as-thesis tests itself. This aspect can also be powerful marketing, and indeed there is no way to trump the marketing advantage of credibility, wherever that credibility might be derived. Science grounds its marketing in the devices it serves to create, and it is precisely this presence which gives it credibility among the general population. Any analogous aesthetic satisfaction is not so concrete, and the arguments and decisions which underly a performance are even that much farther removed from a specific evaluation. There are ideas on reconstructing the past based on limited information, and there is the entire body of theory which instructs us in both semiology and appraisal, but these aspects necessarily become secondary to the human element of performance which presents the face of music. In that sense, the fact that our own preconceived notions condition all aspects of historical performance can be seen more as a blessing than as a curse, because the slow precession of this feedback cycle actually allows more human credibility in the artistic result than a hypothetical truly authentic performance ever could. Perhaps it is ironic, but outpacing the audience is no more successful here than it is in contemporary composition.
The credibility gap is expressed in different ways in the two situations. For early music, there is a sense among some listeners that the performers must make explicit statements about what they are doing, at least for anything which differs from any performance history the music might have had. It is the development of a separate historically informed performance tradition itself which actually constrains the methods which originally made the movement. As new levels of depth in interpretation are sought, more details in the articulation of the music must be addressed, and frequently those details are at odds with earlier performances but not with any musicological findings. This may serve to disorient the listener, but any reverse demands place the performer in the rather awkward position of defending against choices which were arbitrary in the first place. Perhaps more confusing is the fact that many of the smaller details of performance can neither be defended nor rejected from the available evidence, and essentially come down to personal intuition cross-checked against results farther afield. This is a real divergence between performance and musicology, as incidental details necessary for performance will then infiltrate listeners' musicological expectations, while a lack of risk-taking will not allow the performer to develop as an artist. It becomes a question of whether musicology is serving performance or vice versa, and the experimental nature of many performances can create a credibility gap with listeners, especially when the results are disputed on all sides. Oddly, for contemporary music, a wealth of discussion and argument has not helped. If anything, a divergence between the rhetoric and sonic perceptions has alienated listeners further, even when the objectives are laid out quite clearly.
Although issues of credibility are certainly significant to what I am calling the post-authentic phase of performance practice, the phase in which levels of detail are sought finer than those for which evidence exists, there remains the question of exactly what audiences need to believe. A basic fact of disputation is that people who are generally accepting can be put off by more verbiage, whereas people who are not will often not be satisfied anyway. There is a natural tendency to grasp at credibility, but human nature suggests that a succinct statement should be left at that. While suspending disbelief may not be productive for someone asking to be educated on the history of music, the purely artistic end of the music can often be served well by a "belief" in even absurd positions. Such a suggestion can be difficult to reconcile with the sophistication these interpretations frequently demand, but there must be a point at which art is no longer about the rational. The ultimate credibility is in one's own artistic sensibilities, even when mediated by a more rational eye toward historical evidence. There must be a belief that what one is recreating or hearing is great art, and is worthwhile on that basis. The goal of music-as-art is to make a truly living interpretation, and so issues of historical credibility should not stifle an emerging idea, even if the relevant footnotes & explanations must be added by someone else at a later date. This is especially true as we move into the post-authentic phase.