What have you done to the cat, Erwin? He looks half dead."
- Mrs. Schrödinger.
The above quotation is attributed to Erwin Schrödinger's wife – apparently an early animal rights activist. The rest, as they say, is history.
I was reminded of Schrödinger’s Cat after reading this comment and this comment recently. Each of these commenters enlisted Schrödinger’s Cat to prove some
facts woo they were promoting. Unfortunately for them it does no such thing.
First, for those unfamiliar with it, a summary of the Schrödinger’s Cat thought experiment:
Schrödinger imagined that a cat is locked in a box, along with a radioactive atom that is connected to a vial containing a deadly poison. If the atom decays, it causes the vial to smash and the cat to be killed. When the box is closed we do not know if the atom has decayed or not, which means that [the cat] can be in both the decayed state and the non-decayed state at the same time. Therefore, the cat is both dead and alive at the same time...
Note: the cat is both dead and alive at the same time. The woo’s argument goes: this is really weird and counterintuitive, therefore __________ (insert preferred brand of woo) is real. There are several flaws in this line of reasoning.
First, from this translation of Schrödinger's original "cat paradox paper", we know that Schrödinger was deliberately presenting this dead and alive scenario as a “quite ridiculous” case. In other words, since a cat obviously cannot be both dead and alive at the same time, the extreme version of the Copenhagen interpretation (the version that says consciousness is necessary), must be wrong. This could be because “observation” really means “measurement” (ie the Geiger counter measuring the atomic decay is the “observer”), or because Copenhagen itself is wrong. Either way, it is amusing when woos throw Schrödinger’s Cat into the debate, quite oblivious to the fact that is was designed to show the exact opposite of what they think it shows.
But there is a more fundamental reason Schrödinger’s Cat doesn’t support the woo position.
I Taught I Taw A Puddy Tat
Schrödinger’s Cat is a thought experiment only. Thought experiments can be useful to explain a complex idea, or to get people to question assumptions, but a thought experiment cannot by itself prove or disprove anything. To prove or disprove something, you have to perform a real experiment. Schrödinger’s Cat has never actually been performed as a real experiment, and in my view could never even in principle be performed as a real experiment. The reason should be obvious. Schrödinger’s Cat says the cat is both dead and alive until we look at it. But we cannot tell if the cat is dead or alive until we look at it. It’s Catch-22: to perform Schrödinger’s Cat we’d have to look at the experiment without looking at it. Clearly impossible. So it proves nothing.
Of course, this also means that Schrödinger’s point wasn’t proven either: since we can’t say for sure that the cat isn’t both dead and alive, we can’t say if Copenhagen is right or wrong. The “consciousness is necessary” interpretation of QM is unfalsifiable.
But even if the experiment could be performed, and the dead and alive at the same time position confirmed, that still wouldn’t support the many woo claims made for quantum mechanics. If you want to demonstrate that something is true, you need to show some actual evidence that the thing actually is true. Just because quantum mechanics is weird and counterintuitive yet true, it doesn’t follow that any weird and counterintuitive woo is also true.
Poor Puddy Tat!