• Jeremiah
    212
    I keep running into two different concepts of randomness, so I wanted to see what you all think.

    Is random the unpredictable?

    Or

    Is random a situation with various possible outcomes?
  • Cavacava
    886
    I think what is unpredictable ("behaving or occurring in a way that is not expected") is not the same as what is random, even though their usage is frequently interchangeable. I can't predict when the next volcano will erupt, but this phenomena is localized to volcanoes. The idea randomness ("made, done, happening, or chosen without method or conscious decision") does not seem to have any specificity beyond its unpredictability.

    Perhaps 'unpredictability' contains a bit of anthropomorphism of experience, while randomness suggests a state of affairs?

    Doesn't unpredictability suggest an unsuccessful attempt to predict, while random seems to have no such implication.
  • apokrisis
    1.4k
    Randomness can be described equally well as either epistemic uncertainty or ontic indifference. We don't know which number the roulette wheel will roll. And the design of the roulette wheel has a symmety that makes it indifferent as to which number it rolls.
  • Jeremiah
    212
    But there are various variables that influences the number it rolls, which we simply are unable to see. We assume symmetry, but how precise is that symmetry? For all we know the cycle of the moon, or the time of the day could affect the number it lands on. So is it our inability to see all the variables and how it plays out that makes it unpredictable?

    If so, then what does this mean when we select something at random? That we don't know what we are gonna get?

    But what if we select something at random out of say 10 possible choices? Then we know what we are gonna get; we are gonna get one of the 10 possible choices, but it was still a random selection. Is that saying we have simply removed the decision form our hands, and allowed variables we can't see to make the selection?
  • apokrisis
    1.4k
    But there are various variables that influences the number it rolls, which we simply are unable to see. We assume symmetry, but how precise is that symmetry?Jeremiah

    Nature doesn't produce dice. Only humans do. However they still illustrate the essential principle of how to understand randomness or spontaneity in nature.

    So you are making the standard Laplacian complaint that, in principle, complete knowledge of nature is possible, and so all future events can be calculated from determinate microphysical laws.

    Well firstly, we now know that Newtonianism in fact fails at the limits. Quantum mechanics says existence is irreducibly indeterministic - and that ontic claim can even be phrased epistemically in terms of this being due to the fact we can't ask two different (non-commutating) questions of reality simultaneously. Like where are you exactly/what is your momentum exactly?

    And complexity theory shows that the very idea of calculation is also self-limiting in this fashion. Because calculation is a digital way of describing an analog world, there is always round-up error in any attempt to model real world events.

    No computer could ever specify the initial conditions of a calculation to an infinite number of decimal places. And if error compounds exponentially while the calculation proceeds in linear time (polynomially), then error must swamp any claims to accuracy in a few steps if it is describing a non-linear or chaotic event (one with less constraints than the kind of regular dynamics that Newtonian mechanics was designed to describe).

    So we know that this idea of a mechanically deterministic universe is itself an idealisation. It is not the "natural state" of nature. Newtonian physics describes the world after it has reached the limit of a process of symmetry breaking and thus spent its many degrees of freedom. It is the world in as determinate state as it can get - yet not actually determinate, as quantum physics and complexity theory reveal.

    Anyway, back to dice and how they illustrate this.

    We make dice as perfect and symmetrical as we need them to be. Which in turn means we are matchingly indifferent to imperfections that are beyond what might affect our purposes in having a die.

    What we want is a die that a thrower can throw in a fashion which leaves them with no way of telling what number will roll. So it must spin easily (bevelled edges) and yet fall flat on one face (break the symmetry of spinning) without favouring any one outcome. So if you are really concerned about dice being fair, you buy machined dice. You pay extra for the engineering and certification.

    You insist on certainty that the die will break symmetry in a way that is entirely spontaneous to you.

    But if you wanted to insist on that level of spontaneity in terms of nature itself, then you would have to get down to harnessing some kind of quantum noise or quantum emission process. Even nature doesn't know when an atom will decay - just that it has a completely exact and predictable poisson distribution. (The propensity to decay remains constant in time - which tells us something deep about the constraints that form nature, that is, our particular Universe.)

    For all we know the cycle of the moon, or the time of the day could affect the number it lands on. So is it our inability to see all the variables and how it plays out that makes it unpredictable?Jeremiah

    When it comes to dice, we could in theory measure these further variables. But until gamblers start troubling casinos with such high tech approaches to beating the house odds, no one has reason to care.

    So the human situation shows directly that randomness is about how much we have practical reasons to care about constraining the physics of events. We don't let gamblers drop dice. They must roll them properly.

    The difficult mental leap - the one I've argued for - is to see that this principle is true of nature also. And quantum physics is the best argument. Nature can only ask questions of itself (hey little particle, what's your exact location/momentum?) to a limited degree of precision. And yet this doesn't really matter on the general scale of things.

    Quantum fluctuations only disrupt nature on the tiniest or hottest possible scale of being. The Universe itself is now so cold and large that it is pretty much entirely classical in practice. There is infinitesimal chance of it doing something "quantum" like winking right out existence, or fluctuating into some other bizzare arrangement.

    So indeterminism is basic to existence. And yet existence has become a place where everything is more or less as good as determined.

    The question then becomes, why do humans still find randomness useful? Why do we invent ways of introducing chance back into the world of dull mechanical routine?

    Obviously it is because we enjoy creating zones of freedom in which we can pit our wits. Games of chance are a way to practice our skills at strategy and prediction against "unpredictable nature". And so the kind of randomness we are really modelling there is the unpredicability, or non-computationality, of complexity.

    We can try to calculate the future. But also such calculation is impossible. Which is where the pleasure and pain of being lucky/unlucky comes in.

    But what if we select something at random out of say 10 possible choices? Then we know what we are gonna get; we are gonna get one of the 10 possible choices, but it was still a random selection. Is that saying we have simply removed the decision form our hands, and allowed variables we can't see to make the selection?Jeremiah

    Yes, you are describing epistemic uncertainty - something we have got mathematically and mechanically good at "manufacturing".

    And then the deeper issue you want to address is ontic uncertainty - the randomness of nature itself.

    And as I say, we can either rely on our own actions to result in our desired level of uncertainty (as i insisting gamblers roll dice properly, and don't bring moon gravity measuring devices with them into the casino). Or we could try to harness uncertainty by tapping into nature's own level of physical indifference. We could get down to quantum level processes. Or step up to uncomputable non-linear or chaotic processes.

    Of course, people will still insist that at the bounding extremes of nature - the micro-physical and the macro-complex - Newtonian determinism must still reign.

    But that is simply old-hat physics. We know that at the limit, things are actually different. The physics of the classical middle ground - the computationally simplest possible physics - no longer applies.
  • Jeremiah
    212
    Nature doesn't produce dice. Only humans do.apokrisis

    Humans are part of nature so if they do, then nature does.

    "So you are making the standard Laplacian complaint that, in principle, complete knowledge of nature is possible, and so all future events can be calculated from determinate microphysical laws."

    No, I am not. I never made any such claim.
  • apokrisis
    1.4k
    Humans are part of nature so if they do, then nature does.Jeremiah

    But nature is an emergent mix of constraints and freedoms. So humans are free to do stuff that nothing else in nature can manage.

    No, I am not. I never made any such claim.Jeremiah

    OK, well you can make it clearer exactly what your ontic commitments are when you say stuff like.....

    For all we know the cycle of the moon, or the time of the day could affect the number it lands on. So is it our inability to see all the variables and how it plays out that makes it unpredictable?Jeremiah
  • Jeremiah
    212


    "OK, well you can make it clearer exactly what your ontic commitments are when you say stuff like..."

    Sure it is right at the start: "For all we know" And also, "our inability to see. . . "

    But it was interesting watching you debate with yourself.
  • apokrisis
    1.4k
    So why mention lunar influences except that it seems reasonable that they might be influences?

    If you actually thought you were suggesting the kind of constraint on the physics of tumbling dice that is patently irrelevant, you should have made that clear. The fact you mentioned it can only be taken to imply you felt it was a likely, if not a definite, ontic possibility.

    Sorry to be so logical about this. To be taken seriously is obviously not what you really want here.
  • Jeremiah
    212


    "Sorry to be so logical about this."

    Is that what you are calling it?
  • apokrisis
    1.4k
    You're a peevish kind of chap, aren't you? But I see that at least you haven't attempted to deny the implications of your choice of words.
  • StreetlightX
    738
    Is random a situation with various possible outcomes?Jeremiah

    Something like this is probably the most useful way to grasp the concept of randomness: as 'equiprobability', or the equality of probable outcomes. Conversely, 'non-randomness', or order, would be the culling of probable outcomes so that some are more likely than others. This 'culling' can be thought of in terms of putting 'restraints' on the range of possible outcomes. Gregory Bateson uses the lovely old image of the monkeys on a typewriter to get the point across:

    "If we find a monkey striking a typewriter apparently at random but in fact writing meaningful prose, we shall look for restraints, either inside the monkey or inside the typewriter. Perhaps the monkey could not strike inappropriate letters; perhaps the type bars could not move if improperly struck; perhaps incorrect letters could not survive on the paper. Somewhere there must have been a circuit which could identify error and eliminate it." (Steps To an Ecology of Mind, "Cybernetic Explanation").

    If, however, one thinks of randomness in terms of equiprobability, the properly interesting question is what the 'ontological status' of 'probability' is. Are there probabilities in nature, or is probability an epistemic concept that has to do with the motivations of an inquirer? I lean towards the latter answer, but there you go.
  • apokrisis
    1.4k
    Are there probabilities in nature, or is probability an epistemic concept that has to do with the motivations of an inquirer? I lean towards the latter answer, but there you go.StreetlightX

    That's surprising. I'm sure you said once you believed that spontaneity was a proper part of nature. Or is equipotential in fact physically impossible for some reason?

    (And "restraints"? LOL. What is this weird jargon you've picked up?)
  • StreetlightX
    738
    It's the word Bateson uses - and yes, I know you like 'constraints'. And I do believe that spontaneity is a part of nature, but probability or possibility isn't the best way to go about thinking it.
  • apokrisis
    1.4k
    So how is spontaneity ontic unpredictability but randomness only epistemic unpredictability?

    Not sounding very thought out.
  • StreetlightX
    738
    Because as per Bergson, possibility as a modal category is always a back-formation: it takes what exists and then retrojects it's possibility as an explanation for it's being. 'Spontinaiety' or rather novelty isn't the realization of abstract possibilities - it's the very creation of possibilities to begin with. Thinking in terms of possibility always forecloses any thought of novelty. It can be useful, but it isn't good metaphysics.
  • apokrisis
    1.4k
    So again - if the issue here is merely epistemic vs properly ontic sources of unpredictability - how could we know when nature is being random and when it is being spontaneous?

    You didn't answer the question, just introduced the further thing of abstract possibility.

    And in mentioning Bergson, are you really wanting to treat chance as a matter of panpsychic will rather than pansemiotic indifference or equipotential?

    Again that is confusing as I didn't think you were in to woo.
  • StreetlightX
    738
    One can accept Bergson's critique of possibility without subscribing to his metaphysics wholesale. Nuance isn't hard. As for your question, I never said anything about predictability or unpredictability - this is a term you seem to have read in to my comments. Feel free however, to clarify what you think you mean by the distinction between ontic and epistemic unpredictability. Given that novelty just is the interruption of any regime of predictability, I don't really have much use for that concept. But then, singularity does seem a concept alien to your whole framework...
  • apokrisis
    1.4k
    So when one observes the world, how can one tell the difference between a random event and a spontaneous event? How do we know that the one is the result of what you call equiprobability, which you say is likely in the mind of the observer, and the other due to spontaneity, which apparently has something to do with wilful nature?

    What is it that you are really trying to say?
  • StreetlightX
    738
    So when one observes the world, how can one tell the difference between a random event and a spontaneous event?apokrisis

    But this is a misformed question: the point is that randomness (qua equiprobability) is indexed to motivations and expectations of an inquirer (not 'mind', btw, a word with much too much metaphysical baggage), and that it's category error to speak of nature as being either random or not random. Nature is a-random, if you like. Hence the malformed question. Perhaps the reason you are so perplexed is that your whole framework of thought is tethered to the notion of possibility, but that's not my problem.

    As an aside, the very idea of the 'will' is also one of the worst posed notions in all of philosophy, so despite your attempt - as per your usual manner - to pin things on me that I don't hold, well... nope, no will here.
  • Terrapin Station
    2.7k


    A random event is an event that isn't determined by antecedents, because there's some degree of acausality involved in antecedents leading to the event in question. An upshot of this is incorrigible unpredictability, at least beyond probabilistic predictability.
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