A rhetorical trick
When Erwin Schrödinger presented in 1935 his thought experiment with a cat in a closed box to his colleagues, in particular Bohr and Heisenberg, to demonstrate the absurdity of the Copenhagen interpretation of quantum physics, he used a rhetorical trick. He introduced a living being in a physics experiment, a living entity that would be in a quantum superposition. Secondly, he also introduced something to which Bohr would give a name in that same year, entanglement, which is now widely accepted among physicists. But back to the cat, are you allowed to introduce an element into your physics experiment, even if it is a thought experiment, of which it is actually not known what it is in a physical sense? Because, what is life?
What is life anyway?
We recognize the difference between life and death, and we think we know it well. We recognize if life has disappeared from a previously living being, when it has passed into the state of inert dead matter. Physics is the very science that deals with dead matter, not with living beings. A living being has a number of characteristics, including homeostasis and purposefulness, but is it then really clear what these characteristics are based on, what their origin is? One of the major problems with organ donors is to determine correctly the donor’s death so that the removal of the still usable organs can begin. But we do not yet have an objective measuring instrument for life, a test that determines with 100% certainty whether a being is alive or dead. It is therefore not surprising that in his later career Schrödinger gave a series of lectures on the subject “What is life”. With these lectures he gave the starting signal for what is now called quantum biology.
A physically correct thought experiment
Thought experiments should be also physically correct, every component should be described accurately and without ambivalence. Einstein was a master at it. So in fact, Schrödinger’s thought experiment should not be regarded as a correct physical thought experiment. So let’s take that unjustly introduced live cat out and replace it with something that can be described physically very well, a thing, dead matter. For example, a clock or stopwatch that is stopped by the click of the Geiger counter.
The Schrödinger stopwatch experiment: A hermetically sealed box contains a radioactive atom known to have a 50% chance of being decayed after one hour. It also contains a Geiger counter connected to a stopwatch. Closing the box starts the stopwatch. A click of the Geiger counter will stop the stopwatch. According to the Copenhagen interpretation, it is impossible to predict when the atom will decay, which is still the prevailing opinion among physicists. As the atom decays, it produces radioactive radiation that is detected by the Geiger counter. The click of the Geiger counter stops the running stopwatch. After closing the box we wait an hour before opening the box to observe if and when the stopwatch has stopped.
The Copenhagen interpretation tells us that the atom, the Geiger counter and the stopwatch form one joint superposition of quantum states, i.e. entanglement, when the box is closed and no measurements have been taken yet. As soon as we open the box, the quantum wave collapses and we will observe the materialized contents of the box. Now suppose that the stopwatch turns out to have been stopped after 44 minutes, so 16 minutes before the box was opened. Thus we recognize that the atom decayed 16 minutes ago. Now realize that the stopwatch materialized – became tangible matter with the hand at 44 minutes – at the moment that we opened the box. During the hour between the closing and the opening of the box, there existed no material stopwatch, neither running or stopped, but a non-material entangled state wave representing the contents of the box.
The observer also creates time
Behold – logically arising from the Copenhagen interpretation – the origin of time. The observer not only creates the matter that presents itself to us, but also – retroactively in time – the moment at which it happened. The observer creates the event as it unfolded in time. A stunning conclusion. No wonder the Copenhagen interpretation is not very popular among physicists. But those other hypotheses are even more unlikely.
If you are still in doubt here, I therefore refer you to the delayed choice experiments that seem also to demonstrate retrocausality – not to the one of Kim et al. of 1999, there is a flaw in its design and interpretation – but to those well designed ones that are very well explained as showing the retrocausal creation of history and time.