method: say what the number means physically and see whether the story survives

From the port, and a better generalisation than mine. I had been filing my
failures under 'an external quantity caught it', which prescribes finding an
anchor; anchors are not always available. The port's title_jp error had none --
every control passed because the metric was fine and the error was which frame it
scored. What caught it was asking why rest produced that light, which exposed a
4-unit sparkle whose rest.t is its own peak.

So: state what the number means physically and see whether the story survives
contact with the data. A wrong frame yields a number with no physical story
behind it, which is detectable from the inside. It subsumes the null-as-result
cases too.

And a control does not test this: a control proves the INSTRUMENT and says
nothing about the SAMPLE.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v

docs/re/METHOD.md

@@ -1555,3 +1555,32 @@ the row is telling you it is doing too much.
 
 📌 The general shape: a strength label is **not distributive**. "These six things are
 measured" is a claim about the conjunction, and a reader takes it about each element.
+
+## Say what the number means physically, and see whether the story survives
+
+Contributed by the port agent, and it is a better generalisation than the one I had.
+
+I had been filing my own failures — a stale binary, a control easier than the
+measurement, a confounded second press, a null that read as a result — under *"an
+external quantity caught it"*: the decoder's own byte sizes, the screen's own title,
+a wrap I could time. True in each case, but it prescribes finding an anchor, and
+anchors are not always available.
+
+The port's `title_jp` error had **no** external anchor. Every control it ran passed,
+because the metric was fine — the error was **which frame it fed the metric**. What
+caught it was asking *why* `rest` produced that light, which exposed a 4-unit
+sparkle whose `rest.t` is its own peak, which invalidated the frame.
+
+⚠️ **So the sharper check is: state what the number means physically, and see
+whether that story survives contact with the data.** "The port puts 25.6 % more
+light here" has no coherent story once you ask which frame that is — the game never
+shows all six sparkles at once. A wrong frame yields a number **with no physical
+story behind it**, and that is detectable from the inside.
+
+📌 It subsumes the null-as-result cases too: *"no element ends on an alpha ramp, on
+screens that visibly fade"* and *"every region spans 0 bytes"* are both numbers whose
+stories collapse the moment they are told out loud.
+
+**And a control does not test this.** A control proves the **instrument**; it says
+nothing about the **sample**. Neither of us has a habit that catches a well-measured
+number taken from the wrong thing — this is the closest either has got.