Permit me to first apologize for my horrible misspelling of rhythm in my preceding post, the one quoted here.
But where specifically in our counsciousness does the attention to rhythm stem from? I don’t think it’s sufficient to just say “some level of conscious attention.”
It was sufficient for my point of noting that rhythm is primarily associated with a higher-level consciousness, that of a human as opposed to other animals. But, to directly answer your question, as I mentioned in my post, I think you were close to the answer, but the “mathematic” part places it on too high a level, at least for explaining the fundamental aspect of rhythm.
The two-men-walking-in-step example was to highlight how we can automate what was once a fully conscious process. But, take an even simpler example: how many times have you seen (usually) children walking down the street, perhaps touching every car meter they pass, or intentionally stepping to a pattern in the sidewalk? I think of this as a process of ordering, as a way of consciously arranging what we perceive, into a time-ordered pattern.
In general, as a consequence of possesing a consciousness capable of purposefully affecting the physical world, man places order on the world. He seeks the principles which explain what he observes, and he seeks to order sounds and sights which he perceives. It is a natural consequence of a purposeful consciousness, which is why one so rarely ever sees rhythm in other animals of lesser consciousness.
Is this part of that “unknown realm” of music which prevents it from being objectively critiqued? Is it part of some physiology that we have yet to discover?
The problem is, many researchers have not asked the right questions, so the answers which some get do not seem to apply to what you seek to know. The neurophysiology of hearing is not at the knowledge level of the anatomy of the sense mechanism itself. As with much of the cognitive sciences, a failure to grasp the nature of consciousness severely limits what can be achieved.