Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is random a valid scientific cause?

  1. Jul 15, 2012 #1
    Is the use of the term random a valid scientific explanation or just a pseudoname for unknown? I'm asking if it isn't essentially illogical to ascribe the existence of an event, (e.g the origin of the universe) to a random predecessor event. My humble understanding of logic adheres to a cause and effect process (if this / then that). I realize that randomness has been given a fundamental role in reality, via qm. What I'm asking is why randomness (which is the unknown) should be accepted as a logical cause.

    How is logically consistent to rely on an explanation which cites the random action of certain phenomena to be in a certain place and time and having certain properties of spin, etc. etc. as the fundamental cause of macro events which then proceed logically (sequentially and continuously) through space and time.

    Doesn't it seem a stop gap stretch of the imagination explanation, that doesn't refute anything?

    Furthermore, when we look at events which have occurred and which have been calculated to have had infinitessimal likely probablites to have occurred in the time given (e.g. the origin of life on earth) is it not illogical to ascribe these events to randomness? Would the logical person not conclude that something very very improbable would not happen by chance, and that there must be some unknown but overriding reason, which overtook the improbabilities?
  2. jcsd
  3. Jul 15, 2012 #2
    I think random-ness is relative:


    We could guarantee the student's answers were random by, say, presenting the test in Swahili, or otherwise preventing them from even knowing what the questions were, but insisting they guess at the correct answers. Each student might guess true or false according to some non-random pattern, for example, marking all as true, or all as false, or alternating, or marking only prime numbered questions as false, but in the frame of the test the answers can't be regarded as anything but random.
  4. Jul 16, 2012 #3
    Turn your own logic on itself and try to explain in physical terms what "reality" and "causality" are and you'll perhaps appreciate the situation better. Causality and other metaphysical concerns such as "reality" are the purview of philosophy and theology, not physics. As far as I'm concerned those who insist it must be possible to know the mind of God might as well start praying for a miracle. All that Indeterminacy suggests is that it may be impossible for physics to answer such questions and since this isn't the role of science in the first place it is a non-issue.
  5. Jul 16, 2012 #4
    Randomness is indeed a valid explanation, just as possible as any other explanation of phenomena. The main problem is just going about proving it. Since that is impossible, the only way to prove indeterminism is to provide evidence for the impossibility of alternative, causality. At best, though, we can only appeal to negative proofs (QM works somewhat along those lines, but mind you, there are multiple interpretations, not all of which are indeterministic). Perhaps there is nothing to explain, nothing to "refute", but of course, there had better be a good reason for saying that this is so.
  6. Jul 16, 2012 #5
    Randomness is an important part of physics. At the quantum level, nearly nothing is certain and everything happens randomly, but with propabilities that can be determined very precisely.

    At the macroscopic level that you observe directly with your eyes and hands you only see the average outcome of millions of such random events. Knowing the probabilities this average can be calculated with good precision. The laws and formulae derived for these large-number averages must of course match the non-quantum laws of classical physics. This is known as the correspondence principle.


    Using averages to calculate the behavior of observable macroscopic quantities is the underlying basis for all statistical physics. The best-known example is maybe the microscopic derivation of thermodynamics from microscopic origins, statistical mechanics.

  7. Jul 16, 2012 #6
    Does a guy win the lottery because of divine intervention? Of course not. Someone wins the lottery almost every month, even if for each single person the probability of doing so is exteremely slim.

    You argument is usually countered by refering to the Antropic principle.


    Dawkin's The God Delusion has a rather nice discussion of this topic, even if much of the rest of the book is repetitive sledge-hammering of simple reason into thick skulls.
  8. Jul 16, 2012 #7


    User Avatar
    Science Advisor

    rasp - your fundamental assumption is that we live in a universe where all events have a cause. Our empirical data says otherwise - it isn't true that all events have a cause - at the quantum level it appears that things just happen with no underlying cause.
  9. Jul 16, 2012 #8
    I'm not disputing that there appears to be both true randomness in qm systems, and the different seemingly random nature of chaotic systems, whose causes are unknown but not unknowable in principle, as well as other systems like you mention which have large numbers of elements and which can only be described statistically.

    My question is one of philisophical integrity, "should we be allowed to say that the original cause of some event is random, when by random we really mean unknowable?" Should we not attach an asterick to every explanation which employs random, to simply say unknown?
  10. Jul 16, 2012 #9
    Phyzguy, you're correct about my assumption. But on the other hand to accept the evidence that things happen without cause is to deny the fundamentals of logic, which could lead one to even deny the logic one has reached that things happen without cause.

    My solution is to suspend my belief that things "just happen" at the quantum level so as not deny the logic of cause and effect, until such time as science advances further.

    For all I know, in the future we may find a new type of mathematics in which random numbers can be generated by algorithms that do have a shorter information content than the actual number. Such a finding would point to the liklihood that there are physical systems which generate random events.
  11. Jul 16, 2012 #10
    Logic is a tool, not a form of metaphysics. There isn't even one type of logic, but several like having a variety or different screwdrivers to chose from. This is a category mistake of the worst kind.

    Science is about objectivity, not metaphysics and denial.
    Last edited by a moderator: Jul 16, 2012
  12. Jul 16, 2012 #11
    Some things in physics are fundamentally random=unknowable. The decay of radioactive nuclei is one example. No one can predict when a radioactive nucleus, left on its own will, decay. Schrödinger's famous cat illustrates that such random effects can directly affect the macroscopic world. It goes even further in saying that a quantum system will not "decide" in what state it is unless an observation takes place. A more mundane example is the double-slit experiment, in particular if carried out with "delayed choice". There is no intuitive interpretation of the experiment, yet the formulae always give the right answer.

    The quantum world is strange and counter-intuitive in many ways. But it is mathematically self-consistent, and it describes the physical world as observed through measurements and experiments in great detail and with extreme precision. Randomness is an integral part of QM and it cannot be removed. Bell's theorem shows that the randomness can not be attributed to "hidden variables" that could in turn be observed by further experiments.

    Things happen without a cause of reason. In the case of nuclear decay, there is no cause for the time of decay, but physics tells you that the decay must happen sooner or later. For the when, QM only gives you probabilities.

    Randomness is part of reality. Deal with it.
  13. Jul 16, 2012 #12
    Is OPs premise accurate? My understanding of QM is that randomness is not a fundamental property, but rather probabilistic.

    By OPs presumption, I could turn into a balloon at any time if the universe were truly random. The universe might have the possibility for a state that seems random (we can't predict that state), but that probability is very low, so I would not call it random.
  14. Jul 16, 2012 #13


    User Avatar

    Staff: Mentor

    Random is not the same as unknown/unknowable. It doesn't mean a pattern we haven't figured out yet, it means no pattern.

    Also, this has nothing to do with lack of "cause". Radioactive atoms decay because they are unstable.
    Last edited: Jul 16, 2012
  15. Jul 16, 2012 #14


    User Avatar

    Staff: Mentor

    The fact that a process has a random component does not mean it is completely without order/constraints. A process like decay includes random and non-random elements superimposed on each other.
  16. Jul 16, 2012 #15
    But how can you separate random events from non random events? Aren't they all just events with different degrees of probability?
  17. Jul 16, 2012 #16

    Then we have never seen randomness.
  18. Jul 16, 2012 #17
    Randomness is a scientific concept since it is falsifiable.
  19. Jul 16, 2012 #18


    User Avatar
    Science Advisor

    Whether or not everything has a cause is not a question of logic, but an empirical question to be decided by observation and experiment. You statement is like my saying that "logic says that if I'm walking forward at 10 miles/hour and I throw a ball forward at 10 miles/hour, the ball will be going at 20 miles/hour." You may think that's what logic says, but experiment says otherwise.
  20. Jul 16, 2012 #19
    Randomness is an assumption even in quantum physics, the OP is right about that.
  21. Jul 16, 2012 #20

    No, it's not falsifiable. This thread belongs to philosophy.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Is random a valid scientific cause?
  1. Scientific honesty (Replies: 5)

  2. Scientific Experiments (Replies: 77)

  3. The Scientific Method (Replies: 19)