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I am vaguely aware of Heizenberg’s uncertainty principle and the Schrodinger’s cat experiment but how do they relate to current thinking on the exsistence of true randomness in the world? Can two outcomes be reached from identical starting points?

I am vaguely aware of Heisenberg’s uncertainty principle and the Schrödinger’s cat experiment but how do they relate to current thinking on the existence of true randomness in the world? Can two outcomes be reached from identical starting points?

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  1. Heisenberg's uncertainty principle states that the uncertainty in the position of the particle times the uncertainty in its velocity times the mass of the particle can never be smaller than a certain quantity (Planck’s constant). i.e. It is impossible to assign definite values of certain pairs of variables, such as position and momentum, with arbitrary precision for any type of sub-atomic particle using any method of measurement. (For an example visit the Heisenberg's Uncertainty Principle Beinformed page)

  2. Heisenberg's uncertainty principle is important in that it proves that the first premise in the theory of determinism is false. Laplace in his Philosophical Essay on Probabilities (1814) described determinism thus:

    "An intellect which at any given moment knew all the forces that animate Nature and THE MUTUAL POSITIONS OF THE BEINGS THAT COMPRISE IT, if this intellect were vast enough to submit its data to analysis, could condense into a single formula the movement of the greatest bodies of the universe and that of the lightest atom: for such an intellect nothing could be uncertain; and the future just like the past would be present before our eyes."

    Heisenberg proved that "the mutual positions of the beings that comprise it" could never be found.

  3. Schrödinger's cat is an example of the quantum measurement paradox. In this thought experiment a cat is placed in a box, along with a radioactive atom that is connected to a vial containing a deadly poison. If the atom decays, it causes the vial to be smashed and the cat to be killed. When the box is closed we do not know if the atom has decayed or not. However, the atom is a quantum system, which means that it can be in both the decayed and non-decayed state at the same time. Therefore, the cat is also both dead and alive at the same time ­ which clearly does not happen in classical physics (or biology). This is the paradox. It is only when we open the box and look inside (i.e. when we make a measurement) that­ the cat is forced to become either dead or alive.

  4. I think what you need here is Quantum Theory. This theory, which is well accepted, but not well understood, describes particle information, such as it's speed or position, in terms of probabilities (60% chance of being a point A, 10% of being at point B etc.) Only when the particle is observed is it forced to be in one position and it does this according to the probabilities (60% chance of being forced into being a point A, 10% point B etc.). This means that from an identical starting set of probabilities the particle can be measured in two different places i.e. randomness!

  5. I don't know the scientific view point, but is there a conflict between the concept of true randomness and an omnipotent God? If an omnipotent God knows that X will happen tomorrow then, from the definition of omnipotence and "to know", X will happen tomorrow. If our random event is something to do with an object which has no free will, we are left with only two choices.

    a) God decides what will happen which I presume is not random.

    Or b) God has no influence over the object, but can predict what will happen with absolute confidence.

    The question then is: "If an event can be predicted with absolute certainty, all be it by something omnipotent, can it be truly random?". I would say no as predictability and randomness are opposites. The same arguments can be made against the concepts of an omnipotent God and free will.

  6. Comment 5 is the flawed argument of Epistemic Determinism. It is disproved in comment 10 of the debate on free will.

  7. One of the things that we can learn from chaos theory and the concept of fractals is that behind an apparent randomness there's always ignorance and a problem of scale. You may not know the exact position and momentum of two particles of your chair at the same time, but you certainly don't hesitate when you sit on it. It is there with the accuracy you need. With a little thinking it is quite easy (and useful as well) to associate probability with ignorance and atheism with thought barriers.

  8. Comment 7 is wrong. Radioactivity is know to be a truly random occurrence. It is absolutely impossible to predict when an individual radioactive atom will decay. It is not a question of scale. Perhaps this ignorance of probability has created a thought barrier to atheism?

  9. Regarding Schrödinger's cat. What happens if instead of a cat we put in a clock and set it up so that the clock stops when the radioactive atom decays. According to comment 2 until we look in the box the cat is both alive and dead (or in my case that the clock has both stopped and not stopped) and it is only until we open the box that we force it to be one or another. In my case this makes no sense as the clock will display the precise time that the atom decayed and will prove that the 'either or' state never existed. The atom was complete until the time shown and then decayed.

  10. At this point I think it's worth quoting Neils Bohr: "Anyone who can contemplate Quantum Mechanics without getting dizzy hasn't understood it."

  11. The key thing about comment 9 is that you opened the box. Again it is not until you made the measurement of the time of the clock, or the condition of the cat, that you know these things. When the box is closed, the cat and the clock are both in an 'either or' state.

  12. Just because you don't know what state the cat/clock is in does not mean it is in the 'either or' state. Cats die even when they are not being looked at. A human observer is not necessary for things to happen.

  13. But what do we mean, exactly, by randomness? 'At haphazard; without aim, purpose, or fixed principle.' (Oxford Universal) Both "aim" and "purpose" imply intent on someone or something's part, so would imply a god or other intelligence. So we might say "The flat tire was no random event. The perpetrator slashed the victim's tires so he could rob him." 'Fixed principle' suggests something like 'the laws of physics' which require no guiding mind, but are just our inferences drawn from observing how stuff works. So randomness would be an event which is unintended and outside of the laws of physics, and is therefore only a metaphysical concept.

  14. Regarding comment 8, I believe it is a question of scale. If atom decay were random, randomness would exist, but certain things aren't random, so where is the line drawn between that which is declared random and that which isn't? How come that if we shot a laser at a mirror, we could determine where it would be sent next, but it would be absolutely impossible to determine when a radioactive atom will decay? Are you trying to convince me that if something is small enough, it is random? True, we may not be able to determine when the atom will decay, but that does not mean that it happens randomly.

  15. Also n comment 8 : radioactivity is not 'proven' random until it is shown that it is impossible to prove its determinism.

  16. What do we really mean by randomness? If an electron has a 10% chance of being in state A, doesn't this mean that out of 1 billion electrons approximately 10 million will be in state A (pretty definitively!)? How can absolutely random events result in a known distribution over time every time? Doesn't this mean that the "process" (P) is only unpredictable if we reduce the time interval? Sort of dPxdt > h. So, isn't what we call randomness just our degree of "uncertainty in the process"?



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