Radium atoms decay by emitting alpha particles at random. Are these events without cause?

Of course one may take a closer look at radium nuclei to determine a possible reason why they decay; for example a hidden-variables model of QM may provide an explanation.

But the essential question I'm driving at is this: if random events occur in nature are they then by definition without cause? (The above example being simply a concrete illustration).

example: If we find a particular atom decays, and we later find out that its a Radium atom - we could say it decays because it is a Radium atom. In fact this is a tautological statement. We still haven't found the cause.


If an event is determined by its circumstances, only that event occurs and no other. If its undetermined by circumstances, then given something must happen, a range of possible events present themselves. Either all occurs, or one of these possible events occur and this choice must be taken at random, ( for if not, it is determined, and we're not interested in this case here).

An epistemologicaly random event is one which has only the appearance of randomness, given more precise knowledge of the events circumstances, one can determine why this event occurs as opposed to another. For example, a dice throw given Newtonian Mechanics is such an event. If one could precisely know how the dice is thrown and thus model its trajectory one can explain why a five occurs rather than a six.

An ontologically random event is one which knowledge of circumstances is not a barrier; it is random by fiat. In principle completely precise knowledge of circumstances will not enable prediction in a precise sense (a statistical prediction is still possible).

  • Lightnings fall randomly through the most conductive paths, that depend on the random placement of the particles in the air. What is random? What is a cause?
    – Trylks
    Sep 16 '13 at 21:37

Randomness and causation are in different categories. Something can be both random and caused, or random and uncaused (if you believe in such things). Randomness is not a property of origin (cause) but of comprehension (understanding the origin).

Random can mean simply "unpredictable", or "of or characterizing a process of selection in which each item of a set has an equal probability of being chosen." The roll of a die is sufficiently complex such that the outcome is effectively random, but that doesn't mean the outcome was uncaused. It just means the cause was not reasonably predictable with human faculties alone.

EDIT: Response to the updated question
I see how you are defining randomness now, but I can't conceive of any examples in practice because I can't conceive of a universe in which such randomness exists. Radioactive decay is, in my opinion, only stochastic because our science hasn't figured the causal chain yet. I hold that this is more likely than the opposite case because we already have innumerable examples of causation and non-randomness yet we have no examples of the latter. Occam's razor compels me to chose the one that rests upon the least new assumptions.

That said, I can vaguely conceive of a world like you describe. In this world, for something to be truly random, it cannot be part of any causal chain. This suggests to me the answer to your question is yes, ontologically random events are causeless. But this is all very counter-intuitive; we tend to not like the idea that something can come from nothing...

  • I'm not asking about epistemological randomness but ontological. "but, that doesn't mean the outcome was uncaused". You're using an implicit assumption that nature is determinstic; this is something that I specifically said I'm not assuming in the question. Sep 14 '13 at 13:58
  • Could you explain the distinction more clearly in your post? I'm not sure I understand the difference.
    – stoicfury
    Sep 14 '13 at 20:30
  • I've edited the question to try and bring out the differences. Sep 16 '13 at 22:24
  • @stoicfury - Right now there is something and if it did not come from nothing then something has always existed (something is eternal). When something has always existed, then there is no first cause and no finite description how or why everything came to be. Our modern views have an internal disagreement - on one hand, we assert that something cannot come from nothing, on the other hand we assert everything must have a beginning but that contradicts with the logical consequences of the first assertion.
    – Saul
    Sep 17 '13 at 8:59
  • @Saul - Yes, that is the one area we still don't really understand yet. But everything else, turtles, stars, corndogs, pencils.... these things all have causes. I can grant we don't know what the deal is with the very first cause but still rationally hold that everything else does indeed seem to be caused. To me, it's still more rational to believe this than to believe in uncaused events, purely from the number of examples we have in reality alone.
    – stoicfury
    Sep 17 '13 at 21:54


The intuition (as given in one response) that this question involves a distinction between an objective 'origin' and a subjective 'comprehension' is obviously correct, but making such a distinction does not answer the question so much as identify what makes it difficult.

It is true that when we speak about randomness in observed results, we are speaking about limits to our own understanding. However, we dismiss what this question is really asking about if we simply say that everything is caused in reality, and that therefore what we experience as random could and would be experienced as non-random if our faculties were sufficiently powerful.

The question was posed about "actually random events."

This question is related to the old question: is it the case that everything is caused, and do we mean by that that someone or some thing with sufficient faculties could accurately predict the location and qualities of every particle in the universe at some arbitrary date in the future? The current problem begins by assuming up front that the answer to this question is 'no.'


They key to this whole set of related questions is making them even more difficult: just like randomness, the concept of a 'cause' is also an element of our understanding, and therefore a 'cause' is not something straightforwardly real or 'actual.' (The use of the word 'origin' as a substitute for 'cause' tries and fails to avoid this problem by connoting the object which presents itself to us.) The important idea is that "causes and effects are merely a semiotics of the results" of a real process which is more complex and which exists independently of schemas that try to represent it with concepts like 'cause' and 'chance.'

From this perspective, I take the question to be one about (a) the existence of randomness in nature, (b) how we might detect randomness in nature, and (c) whether observed randomness is an observation of the absence of causes.

Limited answer.

My own intuition about these things is that we necessarily experience the world in terms of causes and effects, and that observed randomness is a way of experiencing orders of reality which are not and cannot be experienced directly. They are causeless in the sense that they are not experienced.

There does appear to be a trade-off between how randomly observed variables behave and our ability to explain them in terms of causality. But this speaks to deeper epistemological problems, rather than simply identifying a way of dividing phenomena into two classes: caused and un-caused.


Here is an answer from István Zachar on the physics.SE site which seems to directly answer your question:

It was John Stuart Bell in 1964 who proved by simple arithmetics that there are no hidden local variables behind the statistical nature of quantum processes, and behind the spooky non-locality displayed by entangled particles. Consequently, the paradox presented in the 1935 Einstein-Podolsky-Rosen paper upon which they claimed that quantum physics cannot be complete ("since it relies on statistical laws, it cannot give the ultimate full description of nature") is inherently wrong.

We understand causality as a relation that links post-events (effect) to prior-events (cause) (note that this does not necessarily mean similar chronological sequence, see here). In this sense, observable phenomena are dependent on deeper, possibly hidden variables, that nevertheless can be usually uncovered, at least at the macroscopic level. However, as Bell has proven, there are no hidden variables responsible for lowest-level quantum processes e.g. the random decay of radioactive elements. Therefore I would say that there exist no lower-level, ultimate cause for these processes.

  • 2
    If this is solely a quote from another site (and I see that it is), this is not an answer. You could have just posted the link in a comment.
    – iphigenie
    Sep 16 '13 at 10:02
  • 2
    @iphigenie - I quoted it simply for the sake of convenience.
    – Saul
    Sep 16 '13 at 11:09
  • For the record, to my knowledge we have no specific policies on this (reposting someone else's answer from another site). In this case, it's clear that Saul is not trying to make any claim that the answer is his and is correctly referencing it as an answer from elsewhere, so I think it's fine. That is to say, this answer is useful and does not violate any known policies (again, to my knowledge). :)
    – stoicfury
    Sep 17 '13 at 20:27
  • Why do hidden variables need to be local in order for them to be relevant in causality?
    – labreuer
    Oct 12 '13 at 22:23
  • @labreuer - What else could they be when referring to events local to the observed particle?
    – Saul
    Oct 13 '13 at 9:10

The answer depends on how you define causation. The question 'are random events causeless?' is the result of conflating causation with necessitation. If 'to cause' simply means 'to bring about', then the problem is dissolved. Whether or not the events are random has no bearing on whether or not they have a cause. If the random events are brought about by something, then they are not causeless.

"Causality consists in the derivativeness of the effect from the cause. This is the core, the common feature, of causality in all its kinds” and "Causation, then, is not to be identified with necessitation". These are two quotes (p. 136) from G.E.M. Anscombe's paper ‘Causality and Determination’, The Collected papers of G.E.M. Anscombe Vol. II Metaphysics and the Philosophy of Mind (1981), pp. 133-147, Blackwell). This excellent paper is a great critique of theories of causation which identify causation with necessitation.

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