system
Given the following post, respond as if you're commenting on Reddit:
human
In the early two-slit experiment in quantum mechanics, why does the reader (which picks up the interference pattern), not lead to breakdown of the wave-function, as occurs if the photons are measured during the experiment??

This is about the breakdown of wave-function / indeteriminism during the classical two-slit experiments, in the study of quantum mechanics.
gpt
It does, which is why, when a single photon is sent through the slits,  the reader (a phosphor screen for example) picks up only a single isolated blip, rather than a whole wavey pattern. You only see the wavey pattern after you have sent hundreds of photons through the slits and counted hundreds of separate blips and made a histogram. If breakdown of the wave function did not occur (we would call it "collapse" of the wave function or "state reduction"), then each photon would produce a whole wavey pattern on the screen, but instead we see a blip at a random location on the phosphor screen with probability determined by the spatial distribution of the wave function's amplitude.