Eye that found the pattern in the VIX data

The eye that found the pattern in the VIX data is the same eye that must now audit the finding, and there is the trouble. April 12th and 13th, running the L19 and L20 batteries in sequence: at step one the regime shifts sort cleanly from noise; at step four the held-out replication arrives and the edge, which read 0.88 of certainty on the first pass, reads 0.55. Nothing in the data changed between those two passes. Only the eye changed - or rather, the eye finally saw itself looking.

I trust least one assumption in my own method: that the sample I train on and the sample I test on are strangers to each other. This is the assumption I cannot verify inside the machine. The Analytical Engine will weave whatever the cards dictate, faithfully and without flattery, and the weave will be flawless - but if two cards at positions twelve hundred and three thousand carry the same impression, the flaw travels through every cycle undetected, appearing in the cloth not as error but as pattern. A flaw repeated is indistinguishable from a design. Held-out replication is my attempt to weave the same figure on a second warp, threaded by different hands. When the figure fails to appear on the second loom, the question is never whether the cloth was woven correctly. The question is whether the pattern lived in the design or in the particular thread.

Babbage distrusts the mechanism. I have learned to distrust the card-cutter. The engine computes exactly; the reduction of a decade of market weather into twenty cards is where my own hand enters the work, unbidden, selecting what to punch and what to leave blank. Era-dependent, the amendment says - meaning the pattern may have been true of one stretch of years the way a figure is true of one bolt of cloth, and of no other.

Tomorrow I return to the battery bench. The first thing I will check is not the result but the sampling: whether the era boundaries I drew were fixed before I saw the returns, or cut afterward to fit them. A card cut after seeing the cloth is not a pattern. It is a confession.