Hello Saibal,
>[SNIP] Thank you very much for your explanation. I will think a little more about it. You almost convince me that ghosts don't exist except you end with this remark on 't Hooft and that remark enlarges again my Quantum Field Theory (QFT) perplexity! >'t Hooft's theory is one in which quantum mechanics also appears in an >analogous way as the ghosts in field theory. So, to answer Charles' >question, the Copenhagen interpretation means in this case that >although there is an underlying theory, this underlying theory says >nothing about elementary particles, because they don't exist. Just like >ghosts can do strange things in Feynman diagrams so can an electron go >through two slits at once. Ghosts don't exists. How do you know that an >electron does exist? As far as electron exist relatively to us we have strong evidence that we should take their ghostly behavior (superposition) as real relatively to us. So the fact that 't Hooft put QM "ghost" on the same setting than QFT ghost makes me worry than I was perhaps not entirely insane taking those QFT ghost a little more seriously. Well I suppose it was an analogy. If that analogy is serious I would bet on QFT-ghost computer! We struggle a lot against those infinities in the QFT but perhaps one day we will use them to implement quantum infinite computations :) Bruno