system
Given the following post, respond as if you're commenting on Reddit:
human
Wouldn't the machine in the Schrödinger's Cat thought experiment be "observing" the state of particles, therby collapsing their superposition before doing anything to the cat?

I don't know a whole lot about quantum physics, so sorry if this question just reveals a fundamental lack of understanding :D But it always seemed to me like the obvious answer to why the cat is not simultaniously dead and alive. Observation in the Copenhagen interpretation doesn't require a human being to read the data, does it?
gpt
Yes, and that gets at how the thought experiment would actually work in real life. The box does not completely isolate the cat from the rest of the universe. There are still irreversible interactions going on constantly, where the “environment” (the rest of the universe besides the cat) is essentially measuring the state of the cat. 

This means that the state of the cat can’t be described as a pure quantum state. Instead, you need to have a density matrix describing the cat, coupled with a density matrix of the environment. When you “trace out” the environment, because we’re only interested in the state of the cat, what remains for the cat is no longer a pure superposition state, but rather a classical mixed state. That means that the cat is either alive or dead; the results of a measurement are already predetermined, you just don’t know the answer yet. That’s fundamentally different than a pure superposition state, where the cat is really alive **and** dead, and the results of the measurement are not predetermined. In the case of the pure superposition state, you have all possible knowledge about the state of the cat, but still can’t predict the result. In the case of the mixed state, you have incomplete knowledge about the state of the cat, even though it’s predetermined, and that lack of knowledge is why you can’t predict the result.