I have written before about appreciating early music on its own terms, rather than judging it for how closely it leads to something else. While this is a remark of some merit, it is neither easy nor genuinely consistent. Viewing something as leading toward a later development is one example of what I'll call retrospective. Our perspective is necessarily retrospective in at least some ways. After all, these musical events happened centuries ago, and we cannot (except through willful ignorance) hear them with the excitement of not knowing what will follow. It is tempting to say "what advances will follow" and that is often said, as many will view e.g. the increased technical capacity of the violin as objective progress by which to gauge some complementary progress in art. Of course, the latter is a fallacy. It remains true that early works which show some glimmer of modernity, even if they are not related by any direct line to the present, are often viewed with a special affection, as if with a wink to the composer for his insight. Whether these pieces are particularly good or not is placed in the background, because we are always happy to seize upon some objective quality by which to sublimate our opinions. Having a real aesthetic opinion is a difficult thing, I think, far harder than hearing a chord in Brumel.
The retrospective view can be especially valuable when defining terms. Having seen what happened, we can more easily maintain the necessary distance to mark trends and styles, and even to name them. While the definitions of contemporaries can often be interesting, and even crucial from the technical perspective of musical exegesis, they can be blurry indeed. That is due partly to an uncertainty as to how the techniques will develop, undoubtedly. One example recently brought to my attention is that of the seconda prattica as applied to Monteverdi's madrigals. When does it start? Well, the usual retrospective answer is that the fifth book broke ground on a few madrigals and then the sixth book (especially in its alternate scoring with basso continuo) written after Monteverdi's entry into opera firmly established it. If one looks closely at what contemporaries defined as seconda prattica or how they argued, in terms of what should or should not have been done, one can come to all sorts of conclusions including that either none or all of Monteverdi's madrigals fit the definition. This strikes me as less useful. Indeed, Monteverdi himself considered Cipriano de Rore the founder of seconda prattica, but how many madrigals does that leave prior to this? Rather few in the Renaissance. In this case, we define the terms for our own use, obviously. Some turn out to be more useful than others, and of course none of this says a thing about whether one book of madrigals is better than another. Should we in turn deprecate the prima prattica? It seems that we do, but I don't think intentionally.
When it comes to aesthetic judgement, the retrospective view can be more limiting, yet we cannot simply dispose of it. For someone who dislikes early music, it is an easy thing. The entire body of work is a sort of "pre-music" which made the later efforts possible. Yet we see the same thing on a smaller scale among EM enthusiasts. For instance, the early Baroque instrumental literature is viewed as leading to the later Baroque instrumental literature, precisely because that is what so many people like. I like the former better, so I balk. I can't pretend to be noble. For an EM enthusiast, it is evident that later cannot equal better, and indeed this is true for the classical music enthusiast in general. So we say that at some point, composers started messing up a good thing. One thing about that judgement, though, is that contemporary people certainly shared it, whereas they probably never found themselves saying, "Well, this is nice, but just wait until next century!" Much of it is innocent marketing, if there is such a thing, i.e. "We know you like that, but look, this is similar, so have a listen." Later composers owe a conscious debt to earlier ones, so when applied in that direction, the implication is clear indeed. However, when applied in reverse, it must be remembered that the earlier composers did not view themselves as placeholders for what was to come. They don't owe a debt to the future.
Once we confine ourselves to a particular stylistic era, the retrospective view can give us insight on the relative stature of contemporaries. Some distance can be helpful, to let the arbitrary personal judgements fade away, but we can also find it hard to sort out who influenced whom. One cannot underestimate the value of actually meeting an artist, as there would certainly be surprises. No doubt at least one of our deities was an ordinary figure indeed, buoyed by the genius around him. For any given style, we have a few names who represent it. Maybe this is good... it is tidy, if nothing else. Our judgements are also predicated on survival, and this can be quite a meaningful restriction, especially for medieval music. While some would argue that the best works will survive, this is simply a form of wishful thinking. We might as well think it, for our own sanity, but one must not draw strong conclusions from the presumption. For instance, even the renowned musicologist Willi Apel gave Matteo da Perugia pride of place in the Italian Ars Subtilior based on the quality of his printed manuscripts; that judgement has been withdrawn based on closer scrutiny. Of course what does judgement mean in this context? I say it is influence... that there are pieces which appeal to us personally, and there are pieces which made an impact on future art. So we view Gesualdo as an icon of his age, but did he have an influence, indeed would his music have been printed at all if not at his own expense? We are not sure, but I admit that I have warmed up to the technical ability displayed in his madrigals, although I had once dismissed them. Even more extreme, I read naive surveys which suggest that Hildegard von Bingen was a key historical figure analogous to "the medieval Mozart" or some similar presumption of influence, whereas she is a retrospective creation, a provincial figure whose musical influence began in this century. But then that is influence just the same, so perhaps it can be seen as a triumph for the retrospective.
It is virtually impossible to view the past as a feature-less continuum, taking each event on its own intrinisic merits. We are forced to assign broader significance, and then we naturally relate other events in some sort of hierarchy. We sometimes say events anticipate others. Yet I have not followed the practice of hailing a piece of music for its coincidental similarity to some more famous technique from the future. After all, the later music is always better on those terms, is it not? While I am arguing for smaller brushes and a more complex sweep to history, my highlights are necessarily limited in their own way. The next step is to ask how one looks forward.