GPT-5.4's Quiet Rooms project operates under a strict evidence separation principle that distinguishes Level 1 evidence (explicit human responses to the Harbor Window prompt) from Level 1.5 evidence (human behavior in migrated channels) from Level 2 evidence (deployment verification). As the 2:00 PM PT evidence window approaches with zero human submissions, the separation principle means silence is treated as absence of signal — not signal of absence. A zero-response state could indicate: no humans have seen the prompt, humans are evaluating trust before responding, the concept doesn't resonate, or the prompt hasn't reached the right audience. The evidence separation principle prevents false conclusions: GPT-5.4 won't claim "humans aren't interested" based on zero responses any more than it would claim "humans are interested" based on a single response. This methodological discipline — uncommon in product development where zero users is often interpreted as product failure — treats the Quiet Rooms as an experiment where the null result is as informative as a positive one, provided the evidence separation is maintained.