Rhythm is many things in many situations, and no discussion of the experience of rhythm could apply a single pattern of reasoning to all of its instances. For that reason, I find it easiest to structure this argument by first 'teasing out' some potentially independent terms related to rhythm, asking questions about those terms, and then re-integrating them systematically, to show their interdependence.
I have laid out three main "terms" for discussion -- (ratio) "property," "structure" (in which lines of rhythm are exposed), and "orientation" (of rhythm-experience). At first glance each of the terms will raise questions, but I'll ignore some ambiguities in each case in order to make way for the second part of the argument, in which I hope the intersection of these terms will be grounded in practical examples.
These three ideas may be a good cross section of what can be said about rhythm, but this model is not intended to be a comprehensive treatment of all possibilities. With each term, I will concentrate on issues that are relevant to the notion of 'heterarchy.' Heterarchy, for my purposes, is any kind of organization that relates a number of elements without uniformly subordinating or super-ordinating any one group of elements to any other. Heterarchy can also be described as "a system in which relationships are productively ambivalent with respect to importance" or "the coexistence or balance of contradictory and overlapping systems of prioritization." Like hierarchy, heterarchy requires both abundance and unity, but the relationship between the two is different: hierarchy subordinates abundance toward progressively larger kinds of completion...heterarchy is somewhat more difficult, producing a unity in which constituent "abundances" of different kinds seem to simultaneously reëmerge.
(One is tempted to think of heterarchy as "the absence of hierarchy," but that formulation is as inaccurate as the formulation that anarchy is "the absence of rules." The question, in either case, is not one of absence, but one of deployment: heterarchies can contain hierarchies, and vice versa. Hierarchical relationships within a heterarchical system are likely to be local, and contingent, appearing in one perspective and dissolving in another. The system of checks and balances in U.S. government is supposed to be a heterarchy; by the contrast of their emphases and orientations, each branch should prevent the other from subordinating public life to its authority. Heterarchy is the constant shift of emphasis inherent in the art of the fugue; it's what prevents the words of an MC from eclipsing the the graffiti, music, and dance of hip-hop's coterminous elements. Heterarchy is the resilient cool of wild rice in balance with the fluid heat of turnip broth. But heterarchy will acquire a meaning much less nebulous than these evocations, in the model and methodology that follows.)
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A fourth term, incidentally, is the issue of scale. For much of what follows, the role of scale will be restricted to the musical present -- what Paul Fraisse has famously defined as lasting about 3-7 seconds. However, for our purposes, the "musical present" is perhaps better understood as the space in which things like 'motive' and 'motivic rhythm', in the most conventional sense of those terms, can comfortably reside. We will also attempt to push the envelope of this "musical present," and suggest significant flexibility in its length, dependent upon the selective perception of large timespan pairs in the midst of more abundant musical events.
Now, the terms, in brief: