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Quantum Mechanics and Determinism?

  1. Jul 29, 2006 #1
    Is quantum mechanics deterministic? It argues that probabilistic events occur, does it not? However, if these events occur, couldn't one say that the result of a probabilistic event was not caused? If it was caused, it would be determined and not probabilistic, would it not? Given this assumption, does quantum mechanics believe in randomness? If randomness is the absence of causation, how can one argue logically that something can happen without giving a causation?


    Very Confused
  2. jcsd
  3. Jul 29, 2006 #2


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    In a quantum interaction SOMETHING is caused. The probability is of what particular thing that is.
  4. Jul 29, 2006 #3
    Ok, that helps. However, how can something be caused to have more than one possible cause? Shouldn't the variables ultimately be predictable?

    Here is an example of what I mean. There is a probability of 50% that either A or B will be the result. However, A is the resultant. Therefore, A becomes the cause. However, the fact that A is the cause, consequently ddue to causation, must have a cause itself.

    If that cause is probability, what is the cause or probability? If probability has a cause, isn't the resultant or probabalistic events really the result of a deterministic universe?

    In short, I am trying to reconcile hard determinism with quantum mechanics as Einstein (for a reason I am unsure of) and others seem to say they cannot be combined.
  5. Jul 29, 2006 #4
    The cause of quantum probability is still a fringe area of study and has many controversial ideas. One such controversial idea is that probabilities are Bayesian, or that they are caused by other probabilities.

    That may not be immediately satisfying, so perhaps what you're looking for is an interpretation of probability itself and what it means. Bayes defined probability as a "degree to which a person believes a proposition."

    So the cause of quantum probability, according to Bayes, would be something in nature that causes a person to have that degree of belief in a proposed measured value in quantum mechanics.
    Last edited: Jul 29, 2006
  6. Jul 30, 2006 #5
    Necessary and Sufficient Causation

    Determinists often claim 'everything has a cause' as both a self-evident principle, and as one which has significant philosophical import. However, the truth of the latter depends, as philosophical questions tend to, one what one means by 'cause'. Sufficient cause: If A, then B. A's cannot occur without B's following on. A's are sufficient to cause B's. But something else, A* could also cause B. Necessary Cause: If B, then A. If B has occured, A must have occured. A is necessary for B. Peter D Jones 13/01/02

    Causation and Explanation

    What caused Smith's death ? According to the coroner, the arsenic he ingested. According to the counsel for the prosecution, his wife. The accounts do not contradict each other, they simply reflect different areas of concern. What causes something is not simply given, it depends on what we are interested in.

    Peter D Jones 08/09/05
    Trigger And Background Causes

    We commonly say that a fire was caused by a dropped match, but that is far from being the one and only cause involved; fires,for instance do not start without oxygen. That sort of consideration is of little interest for many purposes; what is of interest is what isunusual, what is changed, not background conditions that never vary. However, this rule often does not apply to historical or social situations. What is of interest is not so much what triggered a riot, but what led up to it. The assassin of Archduke Ferdinand does not bear the brunt of responsibility for WWI.

    Peter D Jones 08/09/05
    Causality And Corelation
    "Correlation is not causality" is mantra taught to all scientists, sometimes to the point where they cease to believe in causality at all. The problem is that if A is correlated with B it could be that A causes B, B causes A, or both are caused by something else, C. Often the gap is filled in by prejudice. According to the theory of spontaneous generation, decay causes maggots to appear. To the moder understanding, it is the action of organisms that causes decay.

    Strict And Probablistic Causation
    In the present day we have good reason to think of causation as probablistic, as influenceing without determining completely, as in phrases like 'smoking causes cancer', which means 'smoking makes cancer more likely', not '100% of everybody who smokes will get cancer'. If causality really is probablistic, then it is quite prossible to derive causal laws empirically by noting that repeated correlations of events, that events of type B tend to follow on events of type A, what are called 'empirical laws' in science.

    Adherents of the strict version of causality, who believe that for a cause to be a cause it must necessitate its effects, often say that in the case of probablistic causality it is only lack of fine-grained information about the details of a physical situation that causes the appearance of merely probalistic causation. This is not a claim about what probablistic causation means, since probablistic causation is equally well understood by people who don't believe in hidden determining factors. It is not an empirical fact either, since, by definition, hidden determining factors are not apparent. It can hardly be claimed as something that can be argued for logically either, since arguments for strict determinism need to refute non-strict, probabilistic causation, and cannot do that without appealing, in a vicious circle, to the very assumption of underlying determinism in question.

    Peter D Jones 13/01/02
    Natural And Agentive Causation.

    Natural causation seeks to bring all events under a set of universal laws. Agentive causation appeals to the irreducible individuality of agents.

    Natural causation works from the past to the future. Agentive causation is puposive and works, concpetually at least towards the future.

    Natural causation is factual. Agentive causation is evaluative.

    Natural causation is external -- the cause of an event is always outside it. Agentive causation is internal -- agents are self-determining.

    Peter D Jones 08/09/05
    Occurrent and Metaphysical Causation

    (From "A Defense of Emergent Downward Causation" by Teed Rockwell)

    "I am going to refer to this common sense concept of causality as occurrent causality, and I want to distinguish it from what I will call metaphysical causality. When I refer to the metaphysical cause of an event, I mean everything in the universe that was responsible for that event taking place, whether anyone knew about it, or was able to have any control of it. A metaphysical cause, unlike a occurrent cause, cannot be described with a single sentence. But it is ontologically more fundamental, because it is less dependent on particular perspectives and projects than is occurrent causality."

    Implementational and Higher-Level Causation

    In the same way that causally relevant factors sink into the background as far as "occurrent" or "trigger" causation, so there is a class of systems in which the "implementation" or "hardware" sinks into the background compared to a high-level functional description. Computers are one example of such a system; to know what a computer will do under certain cicumstances, you only need to know how it is programmed. There is a sense in which what is going on is really being done by the hardware, and in which the software is a "mere abstract description" of the hardware. However, from the point of view of Occurent Causation, what is of interest is compact descriptions bringing out salient features of the situation, features which are likely to change, and changes in which are likely to make a difference. A "software" or "abstract" or "high level" description is able to fulfil those criteria admirably.

    And what of the mind ? Even if (token-token) identity is true, even if mental states have no real existence of their own, they are still suitable to feature in causal explanations. We might think that the total physical state is the "real" cause, but we never actually give explanations in terms of real, metaphysical casuation -- there is just too much of it. Moreover, the apparent falsehood of type-type identity (ie the idea that there is no straightforward relationship between a type of mental state, such as anger, or believing oslo is the capital of Sweden, and a type of brain-state) reinforces the explanatory relevance -- and hence the occurent-causal relevance -- of mental states. We can confidently say that John would have behaved differently if his mental state had been different. We cannot confidently say that he would have behaved differently if his brain-state had been different, because considerations of anti-parochialism impell us to believe that there is more than one way of implementing an "angry" state, and therefore the different brain state might be *another* "angry" state. Peter D Jones 22/11/05

  7. Jul 30, 2006 #6


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    By that, do you mean that every event is created by a preceding cause as in "cause and effect"?

    What is the most commonly accepted understanding of radioactive decay? Is radioactive decay:
    1. Caused by some prior indeterministic event.
    2. Caused by some prior deterministic, yet unknowable event.
    3. Not caused by any event, and only the probability of the event occurring is knowable.
  8. Jul 30, 2006 #7


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    Tournsel, thanks for the post, that's a nice review of causation.

    In the past, I've generally called such causes as "smoking causes cancer" or "the reduction of oil and higher demand caused prices to increase" as loose causal relationships. Here, I believe you've defined such things as a "trigger" or "background cause".

    On the other hand, I've also generally defined "strict causal relationship" as those where an effect is directly initiated from a cause and are governed by physical law. Further, those physical laws are essentially determinate and calculable at a classical level. For example, the flow of air around an aircraft wing and the wing's response (often called "wing flutter") can be accurately determined using a combination of computational fluid dynamics and finite element analysis applied to the structure. Granted, the phenomena may have some exceedingly slight and from the perspective of an engineer, insignificant differences which one might suggest are the result of the fact we are modeling molecular level interactions at the classical level. But regardless of this fact, we can suggest these types of interactions are true cause and effect or "strict" cause and effect relationships. Much more strict may be the operation of a computer which has the ability to mask any minor deviations by having set limits as to the operation of its individual parts.

    What then would you call these types of causal relationships? Are you saying these are "natural and agentive causation"? Do you have any other references for such definitions, something in the published literature?
  9. Aug 8, 2006 #8
    This simply reflects macroscopic indeterminability in cause and effect. What we call "causation" at the macroscopic level is very often nothing more than a (less than 100%) correlation between states.

    Again, because macroscopic observations of "causation" are often no more than correlations rather than strict causation in the microphysical sense.

    The problem, as you have highlighted, is in delineating simple correlation from strict causation.

    It does not follow from this macroscopic observation that causation itself is probabilistic. I would argue that we have no more reason to think causation is probabilistic than to think it strictly deterministic.

    That's a big "if".

    The same argument can be applied to the assumption of probabilistic causation! The fact of the matter is that both "probabilistic causation" and "deterministic causation" are premises which must be assumed either true or false - it is not possible to prove either one true or false.

    And therein lies the infinite regress of ultimate responsibility - see for example :


    again "self-determination" leads to infinite regress - see above reference.

    Best Regards
  10. Aug 8, 2006 #9
    Originally Posted by Tournesol
    It is intended to rebut the argument that causaion is detemimnistic by definition. Refuting an argument against X is of course not quite the same
    thing as proving X.

    The overal point is that there are many ways of thinking about
    casuality, so questions like "do quantum events have causes" need
    to be made more precise before they can be answered.

    That is not the point. Again, this addressed against an arguemtn
    against probalsitic causality. The argument has it that only
    scientific methodology can only work with determinism.
    However scientific methodology works without even knowing
    whether underlying determinism or indeterminism is the case.

    Can you definitively state that another genius like the late J.S Bell
    will not come along with a method to test them ?

    I submit that the ultimate extent to which they can be demonstrated is itself unknown.
    Last edited: Aug 8, 2006
  11. Aug 8, 2006 #10
    This definition...

    "Ultimate Responsibility is the premise that an agent is able to act
    autonomously of all external circumstances (past and future) and
    yet still be in control of its actions."

    ...may well involve a regress, but it is not the definition I am using,
    which is this...

    "(UR), the idea that there is a genuine sense in which you are the originator of your voluntary acts, and therefore bear responsibility for them. "

    Note also the defintion of FW I am using

    "the power or ability to rationally choose and consciously perform actions, at least some of which are not brought about necessarily and inevitably by external circumstances".

    "at least some of which"...that's all.
  12. Aug 9, 2006 #11
    Hi Tournesol

    As I have tried to explain, what we observe at the macroscopic level is often correlation rather than causation. To say that “smoking causes cancer” is thus an incorrect use of the verb “to cause”, to argue that this incorrect use of the verb provides evidence which allows us to refute the premise that causation is deterministic is (imho) false and misleading. All it actually means is that the common English expression “smoking causes cancer” is misleading because it is an inappropriate use of the verb “to cause”. It would be just as incorrect to say that “smoking is responsible for cancer” (but many people do).

    I agree completely. Which is why I disagree with your suggestion that “we have good reason to think of causation as probabilistic”. We don’t. We actually have good reason to think that we often use the verb “to cause” in inappropriate and imprecise ways in common speech, such as “smoking causes cancer”.

    Which “argument has it that” scientific methodology can only work with determinism? I have never seen such an argument, and I would certainly disagree with it if I did see it.

    The point I am making is that we have no way of knowing for certain (at a fundamental level) whether “causation” is either strictly deterministic or probabilistic. But postulating that it is probabilistic does not actually add anything in terms of explanatory power – everything we observe and know about the universe can be explained assuming strict determinism – the hypothesis of probabilistic causation is simply not needed to explain anything at all (except in the minds of libertarians who need the premise of “alternate possibilities”). “Je n'ai pas besoin de cette hypothèse“ as Pierre-Simon Laplace once said to Napoleon.

    Just as definitively as you can say that the premise of probabilistic causation cannot be refuted.

    If you truly believe this, how can you say definitively that the premise of probabilistic causation cannot be refuted?

    The problem is that this simply begs the question of how one is to define “originator”. Surely a genuine “originator” must be able to act autonomously of all external circumstances (past and future) - if not, if the “originator” is in turn determined by other states external to itself, then how can it be genuinely an “originator”?

    How am I to tell whether an agent possesses this “genuine sense” of UR or not? What are the necessary and jointly sufficient conditions for this “genuine sense” of UR? To simply define it as a “genuine sense” begs the question as to how we are to determine whether this sense of UR is “genuine” or not?

    To be ultimately responsible for what you do, you must also be ultimately responsible for the way you are (because the way you are, in absence of mere caprice, determines what you do). But to be ultimately responsible for the way you are, you would have to have intentionally brought it about that you are the way you are. Intentionality is a fundamental aspect of UR (if what we do is not what we intend to do, how can we be held ultimately responsible for what we do?). But to intentionally bring about a certain state N, you must have had a prior state N-1 which led to the intentional development of your state N (if N is an arbitrary state in the sense that you had no state prior to N which intentionally brought about state N, then you can hardly be responsible for state N, can you?). But this also means that state N-1 must have been brought about intentionally in a similar fashion, which means there must have been some prior intentional state N-2…… and so on ad infinitum. UR thus entails an infinite regress of intentional states. The only escape from such regress is to postulate either some arbitrary intentional starting state, or that the self is somehow magically and mystically able to pull itself up by its own bootstraps, the original causa sui (cause of itself).

    Your definition does not mention UR. Do you believe one can have free will without UR?

    Best Regards
    Last edited: Aug 9, 2006
  13. Aug 9, 2006 #12

    This is all rather beside the point. Less-than-strictly-deterministic causation is clearly conceivebale, even if you insist that it is not the proper use of the word "cause". (Which, BTW looks like a "true scotsman"
    argument to me).

    If there is a problem with probablistic causation , it is not that
    it is conceptually incoherent.

    That doesn't follow. Just becuase there is a plurality of ways
    of thinking about causation, it doens't mean that some
    are 100% correct and others are 100% false, and even
    if they are, you have given no reason to think they would
    divide according to your preconceptions. Oh, and you *still*
    can't determine what is real or not just by the "correct" use
    of words. Even if the word "cause" only refers to classical-style
    determinism, quantum physicists are prefectly entitled
    to claim there is empirical evidence of another connecting principle
    between events -- which they would
    repsumably have to call somethign else, a quause, perhaps.

    That is wrong on a number of counts. The Aspect experiment shows tha
    tte universe can only be determinstic if it it is also non-local. Relativity
    indicates that it is local. Indeterminism is also
    useful in explaining spontaneous symmetery-breaking.the large-scale
    structure of the universe and so on.

    Where did I say that ? Perhaps you think probablistic causation
    should not be entertained as a possibility unless it is shown
    to be irrefutably true, whereas determinism should be maintained
    even in the face of countervailing evidence; but that is
    just your prejudice again.

    Well, I define it in terms of "uncaused cause". And I avoid the regress problem by seperating the uncaused causes, in the RIG,
    from ther Rational Self Control in the SIS.

    No. Look at the defintion of FW again.

    "the power or ability to rationally choose and consciously perform actions, at least some of which are not brought about necessarily and inevitably by external circumstances".

    The originator is partly determined and partly undetermined.

    The opposite of "all" is "some or none", not "none".

    By studying the phsyics of indeterminism and the human brian, I suppose.

    As distnguished from a merely conventional sense, e.g. that certain
    pieces of paper are money.

    No it doesn't. I have expalined this issue
    in http://www.geocities.com/peterdjones/det_darwin.html

    Bearing in mind that that only means something other than
    external forces is *partly* responsible for what you are.
    Your "infinite regress" comes about from your -- not my --
    requirement that internal fators at time T-1 are *entirely*
    responsible for my state at time T. If they are only
    partly responsible then the causal chain can "fade put" or
    "taper off". (cf Dennett's "first mammal").

    "the power or ability to rationally choose and consciously perform actions, at least some of which are not brought about necessarily and inevitably by external circumstances".

    An action that is not brough about externally, is brough about
    Last edited: Aug 9, 2006
  14. Aug 10, 2006 #13
    Hi Tournesol

    The above comment is a straw man. Pink fairies at the bottom of my garden are also “conceivable”, but mere “conceivability” is not the issue here. You stated in post #5 :

    and I disagree with that statement. This IS the point. We do not have good reason to think of causation as probabilistic – we have good reason to think that the verb “to cause” in common usage is often misapplied, that many people talk of causation when they should be talking of correlation.

    I have not said that “probabilistic causation” is conceptually incoherent – this is a straw man (and YOU talk about true scotsman arguments)! My argument has been that probabilistic causation is explanatorily inefficacious and unnecessary – everything can be explained on the premise of strict determinism.

    I could say exactly the same about your preconceptions. You choose to define “causation” as probabilistic and to hang on to the notion that smoking causes lung cancer; I instead choose to define “causation” as deterministic and prefer the notion that smoking is correlated with lung cancer. It’s a matter of opinion as to which one is the “better” explanation of the relationship between smoking and lung cancer.

    I am not saying that probabilistic causation cannot exist – I am saying that we do not need to posit its existence in order to explain anything about the world, and lack of clarity in the meaning and use of words in common language leads to the kinds of misconceptions that you have been discussing – such as the strange conclusion “we have good reason to think of causation as probablistic”.

    I’m not sure that many quantum physicists DO talk about causation (or quausation) when talking about the quantum world. John Bell famously used the words “speakable” and “unspeakable” in reference to the differences in epistemology between classical and quantum mechanics. Bell was a determinist – he supported and promoted David Bohm’s views on hidden variables – and I am sure he would have said that it doesn’t matter what name you “call” it, as long as you are consistent and rigorous in your application of that name. To suggest that the verb “to cause” means the same thing when we say “smoking causes lung cancer” as it does when we say “the photon caused the atom to go into an excited state” is not necessarily correct and can lead to misunderstanding.

    The strict interpretation of quantum phenomena is that we see regularities and correlations between quantum states. I doubt that many physicists use naïve language such as “state X causes state Y”. Instead they refer to the probability of consequent state Y given antecedent state X, but in so doing they are not necessarily claiming that this probabilistic relationship is ontic. All we know, all we can know, is limited by our epistemic horizon – we (epistemically) see probabilistic relationships but we cannot safely infer from this that the relationship is (ontically) not strictly deterministic. The correct interpretation is that we just do not know.

    In what way does the theory of relativity indicate that the world is strictly “local”? If you are referring simply to the restriction on speed of information transfer in relativity then this is NOT in contradiction with quantum non-locality as understood in entanglement experiments (what Einstein called “spooky action at a distance” and led to the Aspect experiment via the EPR “paradox” based on naïve relativistic interpretations in the first place).

    There is nothing in this that cannot be explained by indeterminable as opposed to indeterministic effects. Its often a useful approximation to assume strict indeterminism (when I play a game of cards I usually assume the hand I am dealt is genuinely random – but its actually quite determined. The point is that neither I nor anyone else in the game can determine what my hand will be in advance, hence my assumption of randomness is a good approximation).

    I have never said.that determinism should be maintained in the face of countervailing evidence, thus to accuse me of prejudice in this particular respect is just a little disingenuous. The “evidence” points to limits in our ability to know, it points to the world being epistemically indeterminable, but it is simply a leap of faith to jump from this to the conclusion that the world is therefore ontically indeterministic. If anything, I am a free will skeptic and not necessarily a hard determinist. See here for a detailed explanation of the difference :


    If you read my above post #11 you will see the following :

    To my mind, “prejudice” is exemplified by an irrational belief in the premise of probabilistic causation when there is no need for such a premise.

    A genuinely random (indeterministic) event is an “uncaused cause” – but I am sure you are not saying that UR is grounded in random events – or perhaps you are?

    The only way to avoid the problem of infinite regress is either by appeal to supernatiural forces, or by postulating an arbitrary “starting state”. In your RIG/SIS this arbitrary statrting state is the indeterministic nature of the RIG. Are you seriously suggesting that one can be ultimately responsible for a chain of events which originates in indeterminism? I have shown how your model of RIG/SIS does not give rise to anything which could be called UR at :


    Who is using “true scotsman” now? The word “originator” appears in your definition of UR, not in your definition of FW. In fact your definition of FW does not even refer to responsibility, much less ultimate responsibility. Thus I ask again, in reference to your definition of UR, surely a genuine “originator” must be able to act autonomously of all external circumstances (past and future) - if not, if the “originator” is in turn determined by other states external to itself, then how can it be genuinely an “originator”?

    This is the “smoke and mirrors” juggling tactic of the naturalist libertarian magician – to claim that UR is somehow a mysterious combination of determinism and indeterminism (hopping on the determinism foot when his explanation is accused of leading to caprice, and then hopping on the indeterminism foot when his explanation is accused of being deterministic – and hoping that by hopping fast enough from one foot to the other he can somehow “create” an illusion of ultimate responsibility where it doesn't actually exist), without showing exactly how these two can actually combine to produce genuine UR. Your “Darwinian model” certainly doesn’t do it.

    How could we tell whether your Darwinian model gives rise to UR? Or perhaps you are not claiming that it does give rise to UR?

    Is this supposed to be an answer to the question?

    I cannot see an explanation of UR in there. Could you be more explicit? Your website focuses on the need for CHDO and APs as alleged necessary (but not sufficient) conditions for free will, it does not go into much detail on the explanation of how we are to distinguish genuine from non-genuine UR.

    All you seem to explain on the issue of UR is the following :

    But this simply gets back to my question above –

    Are you seriously suggesting that one can be ultimately responsible for a chain of events which originates in indeterminism?

    Again the smoke and mirrors wriggling and hopping of the naturalist libertarian. Where exactly does the UR actually arise? You are saying not in indeterminism, and not in determinism, but in some mysterious conmbination of the two. But there is no such combination which gives rise to UR. Your “fading out” explanation is simply an ackowledgement that UR is grounded in some arbitrary starting state – that we cannot in fact be ultimately responsible for what we are because “what we are” ultimately “fades out” in arbitrariness. I have no problem with this explanation – but this is not “ultimate responsibility” in the sense that most libertarians would wish for.

    From your website :

    The above libertarian “explication” of UR reads more like a determinist’s argument for the incoherency of the notion of UR. To say that Mary’s reasons are simply part of who she is, and that’s that, is exactly what the determinist says. To say that Mary’s reasons are simply part of who she is, is to say that these reasons of Mary’s are not created by any other of Mary’s reasons, and it begs the question of “how did Mary get to be who she is in the first place, and how can it come about that she can be held responsible for who she is?”. The determinists and free will skeptics would agree with the libertarian that Mary’s reasons must be grounded in some X which has no antecedent causal states which may be further attributed to Mary as a responsible individual. Where the libertarian differs is that she assumes there are no antecedent states prior to this X, and that X somehow brings itself into existence not arbitrarily but (somehow) under Mary’s control and therefore responsibility; whereas the determinists and free will skeptics claim that X is itself the consequence of antecedent causal states “outside of or prior to Mary” (or, in the case of free will skeptics, X may simply be arbitrary), and thus Mary cannot possess UR for X.

    To the non-libertarian, the concept that an agent’s reasons may be ultimately grounded in something which is neither determined nor arbitrary is simply inconsistent or incoherent. If determinism and indeterminism are all we have to choose from, then these fundamental reasons X that Mary possesses, the reasons which cannot be traced back to any other of Mary’s reasons, must themselves either have a source which is either determined or arbitrary (this is the approach taken by all camps except for the supernaturalist libertarians), or if neither determined nor arbitrary then the source of Mary’s X must be supernatural (ie beyond rational or logical explanation – this is the approach taken by supernaturalist libertarians).

    Quite. But my question was in fact :
    Best Regards
    Last edited: Aug 10, 2006
  15. Aug 10, 2006 #14
    Commonly accepted understanding is a guide to common acceptance of understanding, and not necessarily a good guide to truth.

    imho the correct (ie true) understanding is a combination of (2) and (3) (they both say that the "cause" is unknowable). imho we cannot in principle know what "causes" the decay, therefore any further attempt at explanation in terms of hidden variables or genuine probabilistic dynamics is mere speculation.

    Best Regards
  16. Aug 10, 2006 #15
    It depends what you mean by "cause". You don't get a radioactive decay event without having a radioisotope in the first place, so such
    events certainly have necessary causes.
  17. Aug 10, 2006 #16
    here we have a "chicken and egg" situation.

    Is it the fact that the atom is a radioactive isotope which "causes" it to decay (what it seems is what you are suggesting), or is it the fact that the atom decays which then "makes it" a radioactive isotope?

    The former assumes a "prescriptive" view of the laws of nature (atoms are necessarily caused to decay because they are radioactive isotopes), and the latter assumes a "descriptive" view of the laws of nature (whatever it is that causes an atom to decay, the fact that it decays then makes it a radioactive isotope by definition).

    Best Regards
  18. Aug 10, 2006 #17


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    Isn't this kind of situation what Aristotle invented his classification of causes for? The fact that the atom is of a radioactive substance is a formal cause. The material cause is that an up quark somewhere in one of the nuclei emits an antineutrino and a W particle and turns into a down quark. What is asked for is an effective cause, of the form "A thingy-bob is struck by a stray antineutrino and fissions into two what-ya-callums, one of which strikes an up quark causing it to emit a W particle and a balancing antineutrino and turn into a down quark." Then the randomness would be reduced to the unpredictability of stray antineutrinos.
  19. Aug 10, 2006 #18
    What makes an atom unstable is the ratio of protons to
    neutrons in the nucleus.
  20. Aug 10, 2006 #19


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    I think this is the best responce to what causes radioactive decay. I'm assuming selfA is not actually suggesting the antineutrino being an actual cause but an example of a potential "effective cause" as he's putting it. One can break the concept down into there being some "formal cause" which is that the atom is a radioactive substance. This is not unlike saying "smoking causes cancer" in that smoking isn't the "effective cause" but what Tournsel describes as a "trigger".

    Regardless of what words you want to define the "effective cause" - for the case of radioactive decay, we don't know if there is such a cause or not. It may be there is a effective cause, and selfA has given an example of what it might be, or it may be there is no effective cause. SelfA, please correct me if I'm miss-quoting you.
  21. Aug 10, 2006 #20


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    Q_Goest you have my meaning exactly. My use of "thingy-bob" and "what-ya-callums" was to indicate that I wasn't proposing a serious explanation, just suggesting the kind of explanation, if one were ever to be discovered, that would fulfill the idea of an effective cause.
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