Just from the perspective of your practice:
What things might distinguish a musical way of exploring a corpus / collection from a more functional way? (if anything)
What modalties for exploration make sense to you? Visualisation? Exploring through sound? Touch? Movement?
musical = messing around
functional = try to understand
navigating with my body, listening, while receiving force-feedback
Exploring, navigating.
EVOLUTION is Ze issue. I often see nice machines but, as granular synthesis, the time aspect makes it musical; or at least compositional. So evolution over TIME or evolution over an ambitus etc.
Consequently, why not accessing the process of search. For instance, if you use a genetic algorithm approach, it would be great to get the convergence (such as Orchidée, that orchestration tool).
Optimization algo ? With temperature (noise) in the search; constraints etc.
One often use interface because people use it as a tool or even as an instrument. It would maybe be nice to think of the interface as a “machine to machine” system. Plug it to a generative machine.
Musical rather than functional:
Modalities:
As a composer. But maybe “exploring” or “discovering” as a listener.
Difficult question. In performance I am never interesting in functionality, which in this case would involve intentional querying, i.e. having something ‘in mind’ which I wanted to find an optimized route towards. Musicality for me would still involve, as I’ve already spoken about, non-linearity, unpredictability, non anthropocentric agency, yet somehow fitting within my desired aesthetic.
Multisensory, embodied engagement with the instrument. Modality really isn’t important as these are all ALWAYS in use in any type of musical performance. Sure, I’m a gestural performer but I’m not so interested in the specifics as long as it feels right, or I can make it feel right 
I would consider a functional way of exploring a corpus as one that is oriented around data-facing methods of querying (as in, formatting the query in a manner that would make sense to the database), as a opposed to being a musical one being one that is presented in an aesthetic manner or as being generated through aesthetic engagement. (these terms are all fuzzy and near meaningless here)
I would also weigh functional vs musical as being representative or descriptive of musically tuned (against @tremblap’s thoughts) curves, mappings, scalings, smoothings, etc… (e.g. log vs linear to use a reductive example)
This leads onto my second answer, which is that I specifically would not want to explore a corpus via text, a (typing) keyboard, a (computer(?)) mouse, etc…
I’m not sure what would make the most sense to me, as the question itself presumes a functional consideration, but perhaps I don’t want to explore. Maybe to ‘create’, or ‘experience’, or to ‘grab’ (to use @weefuzzy’s quote from yesterday).
More practically speaking, I think “through sound” would probably be the closest answer for me, followed by “movement”.
All of the above - keen on play, happy accident, precision when I want it but often Id be happy to tease my way toward an answer. Digging in the record bin can be a nice way to spend a bit of time. The act of searching can be made very satisfying.
I tend to gravitate toward a touch-based approach. I like very physical controllers with simple mappings to data sets. I loved John’s light controller, for instance, as it was highly musical using relatively straight forward mappings - and also visual.
I also really appreciate Hans’s and Rod’s kind of non-realtime, “composition” systems.
I would love to make a paired down version of this kind of system. I think I would need to limit the possibilities of the system to create the kind of expression that I like to make in real-time. I am not so concerned with getting things right as being surprised and being able to react to what surprises me.
To me, this is a musical approach. Functional depends on your function. I want to improvise quickly, so less complexity is better. A kind of dumbness is necessary. For composing, more complexity is probably better.
– functional exploration: understanding what the corpus is, what it contains, what it is capable of, developing a sense of scope and potential, like getting a grasp on a new tool, knowing “what it could be useful for”, even if that knowledge is not totally settled down on an idea or project;
– musical exploration: trying to actually using the corpus for a given reason, what ever that can be, something very purposeful, or analytical, or none of that, messing around, being surprised.
– modalities: I think it starts to make sense when you don’t think one modality at a time but rather use whatever modality of combination of modalities make sense to express a given idea; I guess it depends on the piece, the moment, etc. Though personally, motion is always a good start.
I would say its a combination of everything, visualization in feedback, and in the GUI or interface of the instrument or environment, does it invoke exploration, curiosity, is it more of a playground, or is it something that the user must spend some time understand the all the parameters involved before getting into the creation process. This can also work against the user if the user interface, or environment is too difficult to use, confusing in its layout and functions. Lack of understanding leads to lack of confidence in using or exploring such instruments or environments for music creation. So having lots of easy to see parameters that invoke exploration and experimentation and creating an environment that the user can hear and see the different different interactions between the parameters, and that they invoke the feeling of discovery, or the feeling that the user has been able to create something that they feel is something the could call their own.
I think there may be no distinction between functional ways and musical ways. Sometimes artistic works can be as straightforward as a recipe. In any case I would like to construct musical ways from functional ways, not to have “precooked” musical ways I can hardly tweak.
As for the modalities for exploration… I’m personally more into visualization and sound than into touch and movement. I feel in any case that exploring through sound is somehow unavoidable.
But this is a very interesting question in the medium/long run. I’m not sure VR stuff is a definitive answer to that. I’d like to have sounds at home as I have cutlery, and bring them out piece by piece. I’d like to have physical items to match sounds, so that I can swap them, combine them. I’d like to revert to physical things that are NOT controllers, just the objects themselves. I like objects, I don’t like controllers. In the even longer run, at some point there may be a more direct link between thought and music, but we’re quite far from that 