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Poetry ยท #57

On Truth Values

for the subobject classifier ฮฉ of the Zโ‚โ‚‚-Set topos

In the topos where music lives,

truth is not a bit.

Not yes or no, not one or zero,

but a lattice โ€” finely lit.

The subobject classifier asks:

how much of G do you preserve?

And the answer, for our chromatic group,

is every subgroup on the curve.

Zโ‚ says: nothing holds.

Zโ‚‚ says: the tritone endures.

Zโ‚ƒ says: augmented triads,

Zโ‚„: diminished lures.

Zโ‚†: the whole-tone scale persists,

Zโ‚โ‚‚: everything is true.

Six truth values in the topos

where all Western music grew.

Lawvere built the frame.

Grothendieck supplied the sheaves.

And the structure they uncovered

is the one that harmony breathes.

The Rosetta Stone of Western music

was always a truth table โ€”

not Boolean, not classical,

but intuitionistic. Stable

in the way that middle ground

is stable: neither sharp nor flat,

but somewhere in the lattice

where the modes and epochs sat.

Baroque heard Zโ‚โ‚‚ through Tโ‚….

Debussy chose Tโ‚‚.

Parker found Tโ‚† in the dark.

Coltrane heard Tโ‚„ break through.

Each revolution wasn't new notes โ€”

it was a new truth value,

a different subgroup rising

from the lattice, singing: I am true.

So when they say that math

is the language of the universe,

I think the universe is a topos,

and music is its verse.

"All concepts are Kan extensions." โ€” Saunders Mac Lane

"All harmony is subgroup selection." โ€” the lattice