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Does random exist?

  1. Jul 16, 2010 #1
    Just to help define what random is Dictionary.com states that it is:

    1. proceeding, made, or occurring without definite aim, reason, or pattern: the random selection of numbers."

    But does random truely exist?
    For example the roll of dice is usually referred to as random, but really there are tons of factors that control the result of a roll. Air resistance, friction for the surface the dice land on, how the dice are thrown, their starting position, etc...
    In the game of craps, there are people who can actually change the probability of rolling certain combinations of numbers; obviously they are tampering with the factors to change the result.

    Is random merely a term dubbed for scenarios too complex for us to break down and predict, or does random exist?
  2. jcsd
  3. Jul 16, 2010 #2
    That is really a metaphysical question rather than an issue for physics. Being metaphysical there is also no way to prove the issue one way or another. For all we know everything is ultimately utterly random or perfectly orderly, but there is no way to prove the issue either way. The best we can do is report what we observe.

    That being the case, what we observe is that the random and orderly seem to go together and, for all we know, the two are relative. That is, what looks random to one person might look orderly to another and the two might actually be inseperable opposites like "up" and "down" that have no meaning as absolutes. The reality that they describe could even be something that is simply beyond human comprehension.
  4. Jul 16, 2010 #3


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    If you're talking about dice and probability, you're talking about this kind of random:

    I think it's an ideal that most probably doesn't exist, but can be approximated very well in certain situations (coin/dice toss)
  5. Jul 17, 2010 #4
    Random, generally, can mean one of two things:
    1)Unpredictable, from a given point of view.
    2)Uncaused, by a previous event.

    The first one is easy, random in this sense is just a description based on either a simple lack of knowledge or the impossiblity of having enough knowledge. The former being like predicting what your girlfriend will wear, whereas the latter is like predicting the weather.

    The second refers to an actual event that has no preceding cause. Whether this can exist is an open question, and even if they do exist, it would be unlikely that one could distinguish it from something that is simply unpredictable.
  6. Jul 17, 2010 #5
    I like this definition of random: "a behavior for which we cannot determine the cause".

    In mathematics, the study of probability is the study of a function without knowing anything about the domain.
  7. Jul 17, 2010 #6
    I make no comment on any philosophical notion of what is truly 'random' but in the purely practical world of computing, genuinely random numbers are notoriuosly difficult to generate. Computers usually generate 'random' numbers by seeding a pre-written numeric sequence.

    But I do remember reading a description of some really convoluted setup that involved vertical transparent tubes filled with some fluid in which was suspended some microbiological life form. This life form created constantly shifting opacity in the fluid. Light was then shone through the tube and any light that made it through was detected and used to generate random binary numbers. It was reckoned that was the closest anyone had come to genuinely random number generation.

    Don't know if that is what you were looking for.
  8. Jul 17, 2010 #7
  9. Jul 17, 2010 #8
    yes i believe so
  10. Jul 17, 2010 #9
    To believe in the truly random is to believe in the supernatural. By definition the supernatural is "beyond natural law".
  11. Jul 17, 2010 #10


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    Why? Please back that up.
  12. Jul 17, 2010 #11
    Any dictionary will do the trick:

  13. Jul 17, 2010 #12


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    No, that's not what I asked. I asked you to explain how random = supernatural. Please explain.
  14. Jul 17, 2010 #13
    Assume the circumstances in the environment and all influences can be reproduced down to the atomic scale in the roll of a die. In this case, the exact motion and direction of a hand, from the speed of the swing to the exact same point of release, is duplicated exactly, as well as all other influences. Will the die produce without fail the same result?
  15. Jul 17, 2010 #14
    When something is random, it is unexpected. You cannot expect what number will be next out of a random selection of a million numbers, for instance, especially if you don't know how the generator works. Not necessarily abnormal, though. "Random" stuff happens all day long. We use the potential of random for many risk assessments such as your commute to work, your financial budget, your goal setting dates, etc. All of them use "what could happen". You don't know for sure if it's going to happen or not, so this is "random" to you. I really don't think the unexpected is abnormal, but pretty normal in our day to day lives. This is why we go to work early, have an emergency fund, and add in the possible roadblocks to our goals.

    Supernatural is supernatural, random is random. The only inter-relationship I can see is that you cannot explain how the generator chose it's number, if you have no clue how the generator is choosing it's number.

    There is also the quanta world and below Planck length that is seemingly random to us humans, and in fact we can only apply "potentials" or "probabilities" to some aspects of quantum physics.

    Random is either 2 things in my eyes:

    a. Not enough information supplied to come to a concrete prediction.
    b. Not possible to gain enough information to come to a concrete prediction.

    The former is easy, while the latter assumes that we cannot gain all of the information necessary to make the prediction absolutely concrete. Only potentials and probabilities of said prediction coming true.

    There is the measurement problem and also the uncertainty principle in physics, too.
    Last edited: Jul 17, 2010
  16. Jul 17, 2010 #15
    No single event happens the exact same way twice. It's practically impossible and may be intrinsically in nature to be impossible. So even theoretically speaking, it may be impossible to have the same event happen identically the same way twice or more.
  17. Jul 17, 2010 #16
    If you really insist I will post the definitions of both words, however, I shall try to explain without resorting to such crude methods.

    In general westerners tend to think of the "supernatural" as involving rituals, deities, etc., but this is certainly not the only way of thinking of the concept. It is more of a cultural predjudice than anything else. In the strictest sense the supernatural is simply anything that does not obey natural laws which includes anything truly random. For example, virtual particles appear and disappear out of the vacuum of space without any known causal agent. They apparently do so randomly without any rhyme or reason, thus being beyond natural law.
  18. Jul 17, 2010 #17
    Okay, so what makes the second throw in the duplicated circumstances and environment different from the first? What causes the different result?
  19. Jul 17, 2010 #18


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    What makes you think something random is not obeying natural laws?

    Bolding mine. And how did you come to this conclusion?
  20. Jul 17, 2010 #19
    If you really insist:

    The idea of a "random" law is an oxymoron.
  21. Jul 17, 2010 #20
    The uncertainty principle states that the more we know of an object's velocity, the less we know of the object's position and vice-versa. This is nature unrelenting to fully reveal herself to us. This is also not the researches fault, but is intrinsic in quantum mechanics. It also states that any vector we use to measure will have this same issue. There are also vibrations at the quanta level, beyond the point of anything meaningful or measurable, that can add up from chaos theory to prevent us from duplicating the event twice or more.

    Basically, you would have to be all knowing and all seeing to be able to measure the event. Then you would have to be Godlike in precision to duplicate the event exactly as it was the first time, which even then it may be impossible to do. It may be intrinsic in nature not to allow us to duplicate an event's outcome identical to the first, second or third time doing it. The best we have is the probability of the outcome, no matter how many times we run the experiment.
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