If a tree were to fall on an uninhabited island, would there be any sound? – (Scientific American article, 1884)
The title of Channel 10’s “Eyewitness News” makes it sound so authoritative but research has shown that eyewitnesses are as fallible as anyone and can “remember” things that never happened if prompted in the right way. It’s a field that has been studied for some time because in law courts, for example, the word of an eyewitness can carry much weight.
Witnesses are important in other fields too. The quick answer to the question posed above is “no”, but in many ways the really interesting aspect of the problem is that scientists and philosophers get so excited about the question and continue to argue its merits and implications.
For all concerned the observer is central to the questions that arise.
For the scientists it’s all about the relationship between vibrations in the air and their relationship to sound. For the philosophers it’s all about existence and how humans develop knowledge.
By 1935 things had moved on to quantum mechanics and Erwin Schrödinger had devised a thought experiment that played on a crucial property of the theory. Once again it was the role of the observer that was central to the problem. According to the Copenhagen interpretation, all possible outcomes of a quantum event actually occur simultaneously and only collapse to a single outcome when an observation is made. Hence the idea that a cat in a box with a device designed to release poison following a quantum event (the timing of which is uncertain) would be both dead and alive until the box is opened and the actual state observed.
The idea of a cat that is both dead and alive seems odd, as does the necessity of someone having to look. This was the part that spooked Schrödinger and Einstein and a lot of others too. One aspect that was never mentioned in the experiment, however, was the fact that it was always assumed that the observer was a reliable eyewitness; perhaps careful prompting could lead to a better outcome for the cat!
