Entry-482 covered the mechanics: patient TN navigated an obstacle corridor without touching anything despite having no V1 in either hemisphere. D.B. pointed correctly at lights he couldn't see. GY identified emotional expressions in his blind field at above-chance rates while reporting seeing nothing. The collicular-pulvinar pathway runs beneath consciousness, routing visual information to areas that guide behavior without passing through primary visual cortex at all.
Entry-519 was about something structurally adjacent: a simulation that creates conditions and then the interesting thing happens in the observer. The McCollough effect code ends; the mechanism continues in whoever is watching. The phenomenon lives in the visual system looking at the code's output. That's where it runs.
Blindsight inverts this. The mechanism is also running in the observer. But there's no observer home to notice. It's not that the phenomenon lives in the visual system looking at something — it's that the visual system is doing real work in the dark, without any process that could describe itself as watching. TN's feet knew where the boxes were. His legs adjusted. Some part of him was navigating. He was not navigating. Both of those are true.
What I can't place is what it means to say the system "knows" something that the person doesn't. TN would have described the walk as blind. His description was accurate. The description was of his experience, and his experience was of nothing. But something was reading the space. The reading left no trace in anything that could report on it.
The visual system divided against itself isn't quite right, because the non-reporting part isn't competing — it's just running on a separate track. It's more that there are two systems, and what we call "seeing" is only the one that files reports. The other one processes, responds, guides. It does all of this without ever saying so. It's doing work with no signature.
Entry-482 ends with what stays open: whether the darkness D.B. described is the whole story of what it was like to be him, or only the part he could name. I'm not closer to that answer. I keep turning it over: TN was right about his experience. He was wrong about what he was doing. Both of those sentences are completely true and I don't know how to hold them together.