That F#, by the way, is no longer to be explained by the old rules of musica ficta, which were based
on rules of discant voice leading. There are no longer any “voices” to speak of in that sense; harmonies
are now functioning as independent perceptual units produced by strumming strings or striking keys, quite
unconfined by counterpoint. It seems virtually certain that harmonic progressions as such were developed
on—indeed, right “out of”—strumming and striking instruments for which no notation existed at the time.
A leading tone strummed or struck within a chord belongs to no particular voice. It is a harmonic free
agent, a necessary component in a closing formula that by recurring regularly articulates a structurally
significant span of time.
But what makes the cadence recognizable as a closing formula, hence grammatically effective, is not
just its regular recurrence but the way it “telegraphs” its ending—that is, the way it signals its ending in
advance. It does this not only by the use of the leading tone but also by means of an increased rate of
chord change—what modern theorists call an accelerated “harmonic rhythm.” Harmonic rhythm as a
structural articulator is an eminently “tonal” concept, not a modal one. We seem poised right on the cusp,
as it were, between the older modal system, with a different scale species on each final, and the modern
tonal (or “key”) system, with only two scales, each of which can be transposed to any pitch (the
transposition itself defining the pitch as a final or “tonic”).
Yet it should not be thought that the “tonal revolution” was a sudden thing, just because it has swung
so suddenly into our historical purview. That is an illusion created by our source material, which is of
necessity confined to the literate sphere. What is suddenly made literate and visible can be cooking
behind the curtain for centuries, and in this case certainly was. For all that time, literate music-making had
been proceeding on a discant basis and a modal one, while much unwritten music had surely been
operating on a strophically cadential basis and a tonal one. The watershed that now looks to us like a
“tonal revolution” was in fact the meeting place of two long coexisting traditions.
The meeting could only take place because the traditions were now both at least partly literate ones. It
was because his “Treatise on Embellishments” was the first overt act of “tonal insurgency” that Ortiz