The idea of "fusion music" is certainly not a new one, yet it is a notion in need of refinement. Some discussion of the term is warranted, to avoid being overly vague, as well as to evoke some thoughts on where the trend may be headed. At this point, the surface of possibilities has barely been scratched, and so we can expect fusion music to take on a larger role in the world scene. In popular music, the idea of fusion is usually expressed by the term "crossover" and the genre-mixing implication that usually entails. Of course, popular genres tend to be clearly defined and segmented, and so "crossover" is frequently operating against a real (if contrived) barrier. For world traditional music, cultures themselves tend to be more fluid and so boundaries are more ad hoc and not so rigid. What fusion essentially does is provide a means to combine a variety of ideas in different ways, and to strike off on new styles. Sometimes this happens naturally, sometimes not.
There is a real concern regarding whether any "new styles" are actually any good, and especially whether the core traditions are damaged by the incorporation of ideas from elsewhere. Simple optimism should let us dismiss the latter, although the former is a concern. One can find different themes or instruments transplanted from one tradition to another throughout the history of classical music in the past hundred years. However, many of these applications tend to be naïve or totally isolated, and so are not really fusion. To me, the idea of fusion implies taking traits of two or more traditions and combining them in a fundamental way to produce a new style with roots in both older styles. If the new style ends up having merit, then it should be able to take off on its own while retaining its roots. Due to the huge number of traditional world music styles available to us today, and even the range of classical music styles used simultaneously, the range of possibilities for fusion is enormous. In some ways, the variety available serves to restrict possibilities, because the choices can be overwhelming and so are explored only in particular ways.
One distinctly unexplored area is that of vocal sonority. Although one still finds many Western voice enthusiasts proclaiming confidently that certain Western styles of singing are the only ones which actually develop the voice or provide a range of expression, there are a wide variety of vocal emission techniques used around the world. For someone who finds the standard Western classical voice unpleasant, this range of vocal sonorities is a major attraction. Although issues of language and comprehension have certainly biased fusion efforts toward instrumental or abstract material, the voice is still the most basic human instrument, and can be used in other ways. Vocalise has become an important means of expression in contemporary classical music, and the idea of phonemes as raw material is actually used in more than one world tradition. Even without considering the problems of semantic comprehension, problems which are not really insurmountable, there are a variety of ways in which the voice can be used in a fusion context. The key for me is that it have its distinctive sonority maintained, and not be welded to the insipid Western style.
I may be overly harsh, but concerns on unpleasant and inarticulate voices have certainly been bolstered by the prevalence of this sort of production in early music, and especially in the most popular medieval music performances. While some publications will insist that this sort of noxiously bad singing is the standard of HIP vocal musicality, based apparently on their own preference for the most unobtrusive sound possible, there has actually been something of a move away from the modern cookie-cutter approach to vocal sonority among younger groups. Although the general public appears to enjoy medieval music for its "ethereal" qualities, I cannot help but believe that if its real merits are not disguised, eventually a sympathetic public will enjoy it. Along those lines, HIP itself can be seen as a fusion effort, as it essentially combines a dead tradition recovered in writing with various elements of modern technique to facilitate reproduction. Indeed, world traditional elements have also played a role in HIP developments, and continue to do so. This is a case of fusion-by-necessity, of grafting the dead to the living.
Although early music itself is one conspicuous area in which fusion has played a role, its most significant aspect is in the shaping and continuation of modern traditions. Fusion can be viewed as an inherently postmodern phenomenon, in which a reservoir of basic ideas is used as a dynamic infusion for a culture which has been purged of all real creativity. Indeed, postmodernism as a parasitic worldview demands a continuous injection of new ideas, and so world fusion might serve to prop it up for a few more decades. This idea suggests a "dirtiness" to the whole concept, and consequently re-raises the question of whether the underlying traditions are damaged by fusion ideas. While I still maintain that this view is overly pessimistic, the use of basic material in this way does place a stress on the tradition to maintain itself on its own terms. In many cases, the tradition is strong enough, and so not a concern. However, the sort of feedback process which establishes the greatness of a tradition cannot work instantly on fusion attempts, and so they will be on average less interesting. While that should hardly discourage experimentation, it does mean that one's expectations must be reasonable.
The key to successful fusion is clearly a real organic compatibility between the materials employed. Early Music can be strained in this area, but musicians trained in some particular way want to resurrect a repertory, and so can be excused for the necessity of forcing the issue. In fusion efforts elsewhere, bringing musicians trained in different styles together is one way, but one needs to eventually bring the fusion ideas into the actual minds of individual musicians, and not just the gestalt. A personal connection is essential for developing a new style, and much more haphazardly gained. One thing I'd like to do in the future is turn to some more specific attempts, and I'd be happy to take suggestions in that regard. The basic idea of fusion is certainly simple, and there are many examples available in world music, although an analysis of possibilities or appraisal of trends becomes instantly more complicated. There is also a question of scope, as fusion can take place between similar styles or between very different styles, and those areas involving Western music can be especially productive as topics here.