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

Please verify the authenticity of this law

  1. May 10, 2007 #1
    Law - "Every physical, observable effect has a physical, observable cause preceding it and the cause and effect are related by the laws of interaction of physics"

    Is the above law correct? Has it been published? Can it be disproved? Please give a proof for your argument.

  2. jcsd
  3. May 10, 2007 #2


    User Avatar
    Homework Helper

    So what what the observable cause of the big bang?
  4. May 10, 2007 #3
    May be there was one and we just lack the knowledge of it or didn't get the oppurtunity to observe that observable cause. Can we get into terms with daily life stuff where we can have accurate data?

    I desperately want someone to either disprove the law with adequate data( and not with rhetorical questions) or give me the name of the law and the year when it was published( if it ever was).

  5. May 10, 2007 #4


    User Avatar
    Homework Helper

    It seems to me that the definition of "effect" implies there was a "cause".

    There are effects that current physics don't have an answer for (can't determine the cause), just some theories. This doesn't mean there isn't a cause, but it does mean that there are observable effects that don't have an observable cause.
  6. May 10, 2007 #5
    That 'law' cannot successfully be applied to certain areas of physics, such as quantum mechanics.
  7. May 10, 2007 #6
    Can you be more elaborate? Which part are you exactly reffering to?
  8. May 10, 2007 #7
    Where did you see this 'law' posted? Because the way it is phrased is weird.

    But it looks basically like the definition of Cause and Effect, although, it wouldn't say that they follow the laws of "physics" because "physics" is a study. Maybe if it didn't have the "laws" part, or said "Universe" instead of physics or something, it would make more sense.

    Sure you haven't misquoted it? Or maybe you pulled this particular wording of it out of your ass? :-)
  9. May 10, 2007 #8


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Couple of examples of events without cause:
    - There is no known cause for an atom undergoing radioactive decay.
    - There's no known cause for an electron that changes energy states and emits a photon.
    I believe there are many more in the quantum world, just as Moridin mentions. Perhaps others can name a few more.
  10. May 10, 2007 #9
    First, this is no law. It is a philosophical assumption which is surelly only philosophical and is not meant to be taken literary, as was shown partially that there are many many things which this assumption is not valid. At best this may apply to classical mechanics and I bet thats where we would trace this quote's origin to.

    If one really wants to dig in: What is the difference between cause and effect? What is observable? What does it mean preceeding (consider GR)? Well, this is surelly for first year physics textbook simplification, so they dont get their head spin around in confusion.
  11. May 10, 2007 #10
    This OP as semantically difficulties. By effect do you mean "Change in state"? Also by "Laws of interaction by Physics" i assume you mean "governing principles of the physical world" and since C/E is a relation that is in the physical world by definition it would be a "Laws of interaction by Physics".

    If you mean what i think you mean though, this question can not be proved or disproved.

    It's very close to Hume's question, "Is the past representative of the future"? (we'll call the proposition of an affirmation of this question Q)

    To prove Q true you would need to make a claim about the future (since it's general to all times) but you only have access to the past and present. Thus if P was to offer evidence for Q you would need to assume that P is valid evidence in the future - but to make this assumption you would need Q to be true. So any proof would be circular.

    Suppose now that Q is false, and that P' offers evidence for the falsity of Q. In order for P' to be "evidence" P' is going to have to appeal to some universal fact in/about the physical world (it is clearly that Q isn't NECESSARLY false). But we would have no possible way of knowing this universal fact if Q were false, since information about the physical world is acquired through induction. i.e. We would have to assume that this fact holds in the future in order for it to be truly universal, and it needs to be universal since Q is a universal claim. So the only possible way to prove that Q is false would be if Q were true.

    Thus Q can never be proven or disproved.
  12. May 10, 2007 #11
    I have to admit that the wording in my first post easly allowed chances for
    misinterpretation, so this time let me make it very clear.

    "Is the initiation of an independent chain of events possible?" i.e.
    "Can a chain of events be unconnected to the events that occured in
    the past?"

    Here, i'm not questioning the way you relate two adjacent events in
    space-time(like most of you assumed). I'm merely asking, "Is it
    possible for an event to occur without the necessity for initiation
    from the "already-occured events"? Can there be an instance where
    event 'A' can either occur or not occur and still obey the fundemental
    laws of the universe?

    Is that allowed? If it is, then is it caused by our lack of knowledge
    of the conditions required for the initiaion of A or just that the
    event 'A' can act at its will?

    Hope its clearer this time.
  13. May 11, 2007 #12
    I don't think not "knowing" a cause is equal to not having a cause.
  14. May 11, 2007 #13
    Again this will get you nowhere. If I say that it is possible that chain of events can be unconnected I would be wrong. Since this universe (existance) is already here, thats the primar cause of anything that can happen. Without that, the answer to your question is no.

    However, within the universe (just like creation of universe itself) there are possible events without prior "chain of events". Here you need to sort out the apparent contradiction as I pointed out already, but once you understand that the answer is yes as we already know. And it has nothing to do with our lack of knowledge, its fundamental phonomenon.

    Allow me to digress: When ppl claim that "lack of knowledge does not mean that there is no cause at all", they are already failing to see the prior cause, ie. existance of universe to begin with. Hence we have always knowlege of prior cause. So, I can comfortably claim that any event would not be possible without prior existance of universe and that is its primary cause. Problem solved! Hmmm, but thats not what your question is about I think.

    So even events that do not have immediate causes still are "caused" by the existance of something already. Here Im just repeating myself to show, that things without cause within universe are such only relativelly not absolutelly. But, now we get to the problem of original cause! Well, moder physics interpretors will claim all kind of esotheric explanation but philosophically its unsolved, I its subject to pure belief! :tongue2:

    Needless to say that there are other types of relationships than cause and effect. There are processes where these two are not even definable when cause and effect could be substituted , where causality can by cyclic witch makes effects inseparable from it and hence in classical thinking non-detectable, etc.
  15. May 11, 2007 #14
    The problem with this is, we don't know all the laws of physics yet. Do this statement is neither true or false. Just like Schrodinger's cat.
  16. May 11, 2007 #15


    User Avatar
    Staff Emeritus
    Gold Member

    I think what you're looking for is something close to John Stuart Mill's formulation of the Law of Causation:

    Although his formulation, which he calls the "Principle of the Uniformity of Nature" goes further to assert that similar causes are always succeeded by similar effects, which allows for the possibility of induction. Thus, we can effectively predict the future by having observed enough cases in the past. If set of conditions X obtains, event Y will occur.

    The closest thing I can think of in physics is the law of conservation of momentum, or perhaps just inertia. No massive object can be made to change its motion without the intercession of an outside force. I suppose that doesn't apply to massless particles, which might explain how they can come into and out of existence for no apparent reason, but I don't know jack about physics, so the rest here will need to help with that.

    Oh yeah, Mill formulated his thesis well before the advent of quantum theory, in ignorance of such events.
  17. May 11, 2007 #16
    Actually, that's the symmetry of the laws of nature that you're referring to - not just conservation of momentum. It's the fact that (as far as we know) if you do an experiment in a different place, or a different time, or at a different angle, then as long as the experiment is the same, you will get the same result (except for quantum uncertainty, but we need not get into that).
  18. May 11, 2007 #17
    There is no basis on which to posit a law of causality, accoording to the argument that we never observe causes . When two billiard balls collide all we observe motion, and apparent contact (?), but what does the cause look like? Can you describe 'the cause'?

    More specifically, let us say that there is a moment in time T when the two balls are in contact. We imagine them (as Newton would) as mathematical circles tangent at exactly one point. At any time t > T we have the circles moving apart. The question is: at time T, what happens that we call the cause?

    Some descriptions of classical physics say that something is transfered, but we do not observe the thing which is transfered; this supposed transfer is analogous to epicycles, or some other such positivist mechanism. Its no concern because we have alternatives to sloppy language.

    Now, as for this nonsense about QM and causality, please do not repeat what you read in popular level books, and what you have seen qualitatively described in lectures. If it upsets you that those books contain false information, lies for you to 'learn', then please do your part to stop repeating the information, so that lies from the newspapers of the first half of the century can finally die.

    Lets examine:
    What you are saying is exactly right, on a differentiable manifold with certain properties. Don't confuse nature with a differentiable manifold! All of theoretical physics, including QM, assumes the law of causality (and much more that is no philosophically taken for granted), so Physics does not apply to this thread.

    In fact, the problem with causality is that it is a necessary part of the human experience, but we mistakenly extrapolate it to something real in the world, which it is not (just like emotions are not real in the world).
  19. May 11, 2007 #18
    I dunno. You seem to be saying that there is no objective reality. Earlier, you say that we can't know the cause of a ball's movement because we can't know the underlying "what" of kinetic energy/interia/etc. All this leads to reduction ad nauseam to helplessness.

    We know the ball moves be"cause" something hit it. Otherwise, we might as well just give up. Don't we use cause/effect as a conceptual tool for such events? If this is "sloppy language", I'm missing what we're supposed to use instead.

    In QM, there are situations where causality becomes pretty strange (even setting aside all the popularized junk), but history will show whether QM has the final say.
    Last edited: May 11, 2007
  20. May 12, 2007 #19
    Does anybody have anything to say about zero-point energy effects and causality? I don't follow it well enough to know whether having a minimum energy that can exert a force, but never depletes, is something relevant here.

    P.s. Does anybody know what this is:


    It was on the Wikipedia page. It smacks of a "free energy device", but last I heard, they don't give out patents for those :confused:
    Last edited by a moderator: Apr 22, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Similar Threads for Please verify authenticity
What is the name of this field of science please?