§2 · the writable channel

Small RNA is a reversible write of the drive, resolved into measured species

Small RNA writes the drive h, not the ruler γ: it is reversible (payload cleared, the basin returns), it carries two signs (siRNA→OFF, saRNA→ON), and the measured 12-gene carrier atlas is bistable. Resolved by its biogenesis machinery it splits into miRNA, piRNA, tsRNA and m6A — each a signed drive. [V].

On DICER1 (γ = 1.3981, spinodal 0.6363) a held switch flips only past the opposite spinodal at h = -0.6999, and γ is never edited. Production stability orders by machinery barrier, piRNA deepest.

RNA writes the drive, not the ruler

Driving a held switch with an RNA payload flips it only once the drive passes the opposite spinodal — a hysteretic, memory-bearing flip — while γ stays exactly where it was. That is the defining contrast with an edit: a payload moves the state, an edit moves the SET.

Two signs on one channel

The same channel carries opposite signs: a silencing payload drives the switch OFF, an activating payload drives it ON. One physical channel, a signed write — not two mechanisms.

Reversibility is the through-line

Clear the payload and the basin returns; the correction is reversible and tunable. This is why, later, an RNA vaccine needs no edit and Lever B is the reversible therapeutic lever.

Resolved into measured species

"Small RNA" is not one thing. Split by the measured biogenesis machinery, it resolves into four species, each a signed drive whose production stability is set by its machinery barrier. The ordering is read, never an absolute gain.

The writer/eraser pair is reversible at the mark level too: METTL3 (γ = 1.4104) writes the m6A mark and drives ON, YTHDF2 (γ = 1.4134) erases it and drives OFF — the mark-side twin of payload reversibility. The germline-restricted machinery (piRNA, tsRNA) selects exactly the carriers that can load the gamete; the somatic species cannot.