Richard Feynman wrote:
"It is not our ignorance of the internal gears, of the internal complications, that makes nature appear to have probability in it. It seems to be somehow intrinsic. Someone has said it this way —'Nature herself does not even know which way the electron is going to go'.
A philosopher once said 'It is necessary for the very existence of science that the same conditions always produce the same results'. Well, they do not. You set up the circumstances, with the same conditions every time, and you cannot predict behind which hole you will see the electron. Yet science goes on in spite of it - although the same conditions do not always produce the same results. That makes us unhappy, that we cannot predict exactly what will happen. Incidentally, you could think up a circumstance in which it is very dangerous and serious, and man must know, and still you cannot predict. For instance we could cook up we'd better not, but we could - a scheme by which we set up a photo cell, and one electron to go through, and if we see it behind hole No. 1 we set off the atomic bomb and start World War III, whereas if we see it behind hole No. 2 we make peace feelers and delay the war a little longer. Then the future of man would be dependent on something which no amount of science can predict. The future is unpredictable. What is necessary 'for the very existence of science', and what the characteristics of nature are, are not to be determined by pompous preconditions, they are determined always by the material with which we work, by nature herself. We look, and we see what we find, and we cannot say ahead of time successfully what it is going to look like. The most reasonable possibilities often turn out not to be the situation."
This means that whole Future of mankind and earth can 'potentially' depend on — in which eigenstate of an observable the state vector of a single electron will collapse upon measurement! It appears to me that measurement on a single electron can be linked with such a large scale uncertainty only if an intelligent being decides to do something beforehand on the basis of the possible outcomes of a measurement, to exclude the appeal to extremes we can make a more realistic thought experiment:
Suppose,I decided to do something beforehand on basis of the measurement's outcome.I decide that I will go out and give a party if I find out the electron behind hole 1 and will remain in my home if I found the particle behind hole 2. I found the particle behind hole 2 and remained in home. As we know the act of measurement will force the state vector to collapse in one of the eigenvectors of the operator corresponding to the observable we are measuring, in which eigenvector it will collapse we can't say beforehand.We will get the eigenvalue corresponding to that eigenvector as the result. This uncertainty regarding to the measurement on a single electron could be linked with a significant uncertainty in large macroscopic scale (Me with a 80 kg body, trillions of molecules staying in home OR going 100 km away and dancing in a party is a huge uncertainty in microscopic domain based on the state vector collapse of a single electron!).Is that kind of an uncertainty a measurement on a single electron can produce in macroscopic scale only if a beforehand decision making of an intelligent being involved? In the realm of everyday life and foreseeable technology, a single electron measurement is highly unlikely to be linked with such a large-scale macroscopic uncertainty.
it is making the large scale phenomenon such as future of mankind in first scenario or where I will be in second scinario fundamentally probabilistic "which no amount of science can predict". Isn't it directly linked with the state vector collapse of a single electron? Are there other such processes concering the measurement of a single elementary particle which can make large scale events inherently probabilistic without involving such decision making?
As we know the outcome of a measurement is inherently probabilistic when measured on a single particle but measurement on an identically prepared ensemble will give us almost accurate prediction. For an example what percentage of photon will reflect and what percentage will refract through a particular surface is known. We can predict the intensity of reflected and refracted beam accurately in a macroscopic scale, though what a particular photon will do is uncertain, It seems that a large macroscopic system or an ensemble don't suffer significant uncertainty in prediction, and a decision beforehand based on a single measurement is the only way future of a large macroscopic system can be significantly uncertain. Though the measurement process itself puts a mark on instrument (suppose the photographic plate in single photon double slit experiment) and it is very much uncertain, but this is not sufficiently large scale uncertainty, on measuring huge collection of identical photons we can accurately predict what will be the photon density on each part of the photographic plate i.e the smooth interference pattern. I am not saying QM works only in microscopic domain, it works in every domain (for example; the reason why two solids don't interpenetrate lies in QM, precisely in Pauli's exclusion principle) but I can't remember many large scale examples where significant uncertainty is involved (exept those examples which contains decision making)
I may be completely wrong, just an instantaneous thought.
