Disclaimer: I'm not a physicist. I'm just some random internet dude who likes learning things. My understanding is that a single photon wouldn't count as an observer. It doesn't even experience time (from the point of view of the photon, admission and absorption are simultaneous). Now if that photon is entangled with another photon, that can then be considered an observer. Someone please correct me if this is not accurate.
t8sr|3 years ago
Talking about coherence and [decoherence](https://en.wikipedia.org/wiki/Quantum_decoherence) is IMO a lot more intuitive. Always keep in mind, if you're reading about quantum physics and there's anything in there about consciousness or subjective experience or whatever, then you're either reading something very fringe, or you've misunderstood what the paper is saying. Quantum physics is weird, but it's not that weird.