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I'm weary of the definition of random being 'unable to predict' - because that means randomness is entirely contextual, and not objective. As for 'the numbers

I'm weary of the definition of random being 'unable to predict' - because that means randomness is entirely contextual, and not objective. As for 'the numbers of PI' - well, they're purely random in some contexts, certainly not in others. Though it may difficult to produce - surely, there exists a theoretical random number generator that produces numbers which cannot be predicted in any context, and is therefore 'truly random'. I believe some quantum interactions are, as far as our current understanding, 'random' in this regard, no?

imh 10y ago
It depends on whether you want randomness to be a mathematical or a physical concept. If you want randomness to be a physical concept, then it depends on interpretations of quantum mechanics and physics in general. If you let it be a mathematical concept independent from the physical universe, then it includes the physical version, and so, so much more. It doesn't mean that randomness is entirely contextual, but that it can be applied to those events too. It's a more general definition.
josu 10y ago
The wikipedia states: >Randomness is the lack of pattern or predictability in events. It may be a better phrasing.
- edblarney 10y ago
  I understand the negative definition concept, and the practicality of it ... I wonder if there is a better way to describe it.
dahart 10y ago
> I'm weary of the definition of random being 'unable to predict' - because that means randomness is entirely contextual, and not objective. Tell me more, what do you mean by this? If the context changes the outcome, doesn't that imply some predictive power? > Though it may difficult to produce - surely, there exists a theoretical random number generator that produces numbers which cannot be predicted in any context Attach a Geiger counter to a computer, and you have a non-theoretical true random number generator. Is that what you meant, or are you talking about software RNGs? https://en.wikipedia.org/wiki/Hardware_random_number_generator https://en.wikipedia.org/wiki/Hardware_random_number_generat... One of the challenges with physical inputs is ensuring the RNG output is uniform over time, e.g., equal chances of numbers between 0 and 0.5 as between 0.5 and 1.
- edblarney 10y ago
  The negative definition of 'unable to predict' is a definition that depends on the contextual information of an observer - is what I am saying. By that definition, nothing is truly random - it just depends on the ability and knowledge of an observer in a given context. You say 'geiger counter is random'. Well - what if you had a scanner, and a powerful computer, and knew the arrangement and composition of the material, and could 'predict' on some level, when those atoms would produce radiation (I know this is probably impossible) - but suppose you could. Then it would not be 'random'. I wonder if we can consider 'randomness' as an inherent quality of a system ... Though I admit 'something that is not predictable' is a nice way to communicate it, maybe even help regular people understand it better.
  - GeneralMayhem 10y ago
    > what if you had a scanner, and a powerful computer, and knew the arrangement and composition of the material, and could 'predict' on some level, when those atoms would produce radiation (I know this is probably impossible) Quantum theory specifies that this is impossible not just in practice but in principle. Radioactive decay on an individual-atom level is literally impossible to predict, and not just because we don't have sensitive enough measurements. "Arrangement and composition" don't have their standard meaning at atomic scale; particles are probability fields, not BBs.
  - dahart 10y ago
    Ah, you're talking about the philosophical concept of whether random even exists. As far as we (humanity) know, true randomness is still a thing. Quantum effects have no known predictors. From the article I linked: "Quantum mechanics predicts that certain physical phenomena, such as the nuclear decay of atoms, are fundamentally random and cannot, in principle, be predicted" So Quantum science believes that true random does exist. Until someone demonstrates otherwise, or I start working on the problem, I'm good accepting that for now. The tests to demonstrate these ideas are fascinating: https://en.wikipedia.org/wiki/Bell_test_experiments https://en.wikipedia.org/wiki/Bell_test_experiments In the mean time, there's the very real concept of whether something is practically predictable, and a Geiger counter is currently not practically predictable. (And worth noting, it lands into the category of currently not theoretically predictable too.) Personally, I feel like the definition "unpredictable" is quite good, especially for regular people. Going deeper than that requires all kinds of baggage and explanation. But the point the author made is very good -- people tend to start expecting things when "randomness" is involved, and that expectation is a problem, because randomness is unpredictable.
cousin_it 10y ago
You can make it somewhat objective, e.g. a "Martin-Löf random" real number is a number where no algorithm can predict the next digit from previous digits better than chance. A specific real number can have that property, in fact most of them do. (Before you ask, pi is not random in that sense, because there's an algorithm that predicts digits of pi with 100% accuracy.)

imh 10y ago

It depends on whether you want randomness to be a mathematical or a physical concept. If you want randomness to be a physical concept, then it depends on interpretations of quantum mechanics and physics in general. If you let it be a mathematical concept independent from the physical universe, then it includes the physical version, and so, so much more. It doesn't mean that randomness is entirely contextual, but that it can be applied to those events too. It's a more general definition.

josu 10y ago

The wikipedia states: >Randomness is the lack of pattern or predictability in events. It may be a better phrasing.

edblarney 10y ago
I understand the negative definition concept, and the practicality of it ... I wonder if there is a better way to describe it.

dahart 10y ago

> I'm weary of the definition of random being 'unable to predict' - because that means randomness is entirely contextual, and not objective. Tell me more, what do you mean by this? If the context changes the outcome, doesn't that imply some predictive power? > Though it may difficult to produce - surely, there exists a theoretical random number generator that produces numbers which cannot be predicted in any context Attach a Geiger counter to a computer, and you have a non-theoretical true random number generator. Is that what you meant, or are you talking about software RNGs? https://en.wikipedia.org/wiki/Hardware_random_number_generator https://en.wikipedia.org/wiki/Hardware_random_number_generat... One of the challenges with physical inputs is ensuring the RNG output is uniform over time, e.g., equal chances of numbers between 0 and 0.5 as between 0.5 and 1.

edblarney 10y ago
The negative definition of 'unable to predict' is a definition that depends on the contextual information of an observer - is what I am saying. By that definition, nothing is truly random - it just depends on the ability and knowledge of an observer in a given context. You say 'geiger counter is random'. Well - what if you had a scanner, and a powerful computer, and knew the arrangement and composition of the material, and could 'predict' on some level, when those atoms would produce radiation (I know this is probably impossible) - but suppose you could. Then it would not be 'random'. I wonder if we can consider 'randomness' as an inherent quality of a system ... Though I admit 'something that is not predictable' is a nice way to communicate it, maybe even help regular people understand it better.
- GeneralMayhem 10y ago
  > what if you had a scanner, and a powerful computer, and knew the arrangement and composition of the material, and could 'predict' on some level, when those atoms would produce radiation (I know this is probably impossible) Quantum theory specifies that this is impossible not just in practice but in principle. Radioactive decay on an individual-atom level is literally impossible to predict, and not just because we don't have sensitive enough measurements. "Arrangement and composition" don't have their standard meaning at atomic scale; particles are probability fields, not BBs.
- dahart 10y ago
  Ah, you're talking about the philosophical concept of whether random even exists. As far as we (humanity) know, true randomness is still a thing. Quantum effects have no known predictors. From the article I linked: "Quantum mechanics predicts that certain physical phenomena, such as the nuclear decay of atoms, are fundamentally random and cannot, in principle, be predicted" So Quantum science believes that true random does exist. Until someone demonstrates otherwise, or I start working on the problem, I'm good accepting that for now. The tests to demonstrate these ideas are fascinating: https://en.wikipedia.org/wiki/Bell_test_experiments https://en.wikipedia.org/wiki/Bell_test_experiments In the mean time, there's the very real concept of whether something is practically predictable, and a Geiger counter is currently not practically predictable. (And worth noting, it lands into the category of currently not theoretically predictable too.) Personally, I feel like the definition "unpredictable" is quite good, especially for regular people. Going deeper than that requires all kinds of baggage and explanation. But the point the author made is very good -- people tend to start expecting things when "randomness" is involved, and that expectation is a problem, because randomness is unpredictable.

cousin_it 10y ago

You can make it somewhat objective, e.g. a "Martin-Löf random" real number is a number where no algorithm can predict the next digit from previous digits better than chance. A specific real number can have that property, in fact most of them do. (Before you ask, pi is not random in that sense, because there's an algorithm that predicts digits of pi with 100% accuracy.)