This is the last chapter of the series Named Theories
It is a mental experiment (which only needs to be imagined to reach conclusions) invented by the Austrian physicist Erwin Schrödinger in 1935. The objective was to test the Uncertainty Principle, a theory about quantum physics created by Werner Heisenberg. According to the German, subatomic particles (such as electrons) are in several places and rotating at several simultaneous speeds at the same time – until an observer tries to measure where and how they are, and thus “forces” them to take a single position or speed. That is, observation is able to define reality rather than the other way around.
I threw (or not) the stick at the cat
Calm! The experiment is pure imagination and did not use any real animals.
1. A cat is placed in a sealed box where a single radioactive atom is connected to a measuring apparatus which, in turn, is connected to a hammer. The hammer hangs over a vial of poison. If the meter detects that the radioactive atom has decayed, that is, it has lost an electron, the hammer breaks the flask, the poison leaks out and the cat dies.
2. The probability of this atom losing or not an electron is incalculable. Worse: according to the Uncertainty Principle, the position of this electron is multiple: it is both close to the atomic nucleus (the atom has not decayed) and far away (the atom has decayed) at the same time. Its “definite” position is only determined if someone observes it
3. As the life or death of the cat is directly linked to the position of the electron, and it is in more than one place at the same time, the cat is also in a multiple state: both alive and dead. The cat has no ability to observe the atom, and since the box is sealed, no one can see anything inside.
4. If an observer opens the box and looks inside, he immediately determines, by observation, what position the electron is in, which also defines the life or death of the cat. The paradox is in the strange situation of the cat: to say that observation is what determines the cat’s life or death instead of just registering its state sounds absurd.
Died-reu-reu?
Some interpretations are crazier than the paradox itself
The meter acts as an “observer” and defines the position of the electron long before the box is opened.
When the box is opened, the cat and the viewer “split” into two “worlds” – one in which the cat died and another in which it is alive.
The probability that the atom will decay is not incalculable – it’s just a matter of repeating the experiment enough times to figure out that probability.
SOURCE Stanford Encyclopedia of Philosophy