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How is a system informed by an input that 'carries information'? It processes the input to determine what actions to take next. What details is the system abl

by kd0amg 15y ago

How is a system informed by an input that 'carries information'? It processes the input to determine what actions to take next. What details is the system able to 'learn about' from that input/information? Some facility for conditional execution (not just something like an "if...then...else" control structure -- the ability to compute non-constant functions). What's happening there is just a physical interaction of the 'inputs' interacting with the system. So? How is that information related to the meaning of the information - how does that work? If the brain is just computation, how does the "semantic information" in the brain work? What is "meaning of the information"? What is "semantic information"?

jamesrcole 15y ago
How is a system informed by an input that 'carries information'? -> It processes the input to determine what actions to take next. So what qualifies as an input? What qualifies as an action? How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? What's happening there is just a physical interaction of the 'inputs' interacting with the system. So? See my last point. How is that information related to the meaning of the information - how does that work? If the brain is just computation, how does the "semantic information" in the brain work? -> What is "meaning of the information"? What is "semantic information"? Information informs about certain details, a system can take the information and understand its meaning. 'semantic information' - sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process.
- kd0amg 15y ago
  So what qualifies as an input? That which affects the system What qualifies as an action? Changes in the system's internal state or output How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? You can test whether its state changes in response to external stimuli (n.b. this is no way to test this perfectly). See my last point. Looking back, it seems like you think I've made some claim about the system having "learned" something. Information informs about certain details, a system can take the information and understand its meaning. I agree that a system which computes can take the information and act in a way that depends on it, but what do you mean by "understand"? sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process. This is not a definition of either term I asked about.
  - jamesrcole 15y ago
    So what qualifies as an input? -> That which affects the system That applies to any causal interaction with the system. What do you mean by 'system'? How do you objectively determine whether some physical details are a 'system'? What qualifies as an action? -> Changes in the system's internal state or output Same kinds of issues. What is the objective criteria for 'system', 'internal state', 'output'? What are the relevant sorts of 'changes' - there's all sorts of physical changes that are not relevant. How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? -> You can test whether its state changes in response to external stimuli (n.b. this is no way to test this perfectly). but you need some objective criteria for what changes count as stimuli and what are just "meaningless" interactions with the system. Information informs about certain details, a system can take the information and understand its meaning. -> I agree that a system which computes can take the information and act in a way that depends on it, but what do you mean by "understand"? Act in a way that is appropriate to what the information is about. and btw this is an imprecise and vague description of 'understand'. a proper theoretical account would be a lot more precise. sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process. -> This is not a definition of either term I asked about. these aren't my terms/notions. if you really want to know what people mean by them there's stuff online.
    - kd0amg 15y ago
      Pretty much anything can be considered as a "system," any aspect of it its "internal state," any aspect of it which can affect something else its "output," and any phenomenon that can affect it as "input" or "stimulus" (there is no need for any of these to have any higher "meaning"). The fundamental problem here is that any definition broad enough to encompass everything that can be considered "computation" is going to be too broad to say anything meaningful about the nature of the class of phenomena it describes. Yes, asking what the nature of computation is requires a definition of computation in order to be a well-posed question, but the whole song and dance then reduces to asking about the nature of things that fit some chosen definition (and any definition suffices for playing that game). If you want to learn anything substantial, you'll generally have to pick some particular model of computation to study. You could choose to study deterministic pushdown automata, and then you will learn about computation that fits in that model. Or you could study Markov algorithms and learn about computation that fits in that model. Or you could even study something like Turing machines augmented with halting oracles. For computers that fit a particular model, you can discover things like what they can and can't compute, how quickly they can compute various things, what it takes to convert a computation system defined in that model into another model, etc., and this will all follow from properties of the model you've chosen to study. The only thing common to all models is that they have some way of mapping "input" to "output" via some change in "state." That is not specific enough to draw much further insight, so computation theory tends to talk about particular sets of models (e.g. "anything equivalent to a Turing machine").

by kd0amg 15y ago

jamesrcole 15y ago

How is a system informed by an input that 'carries information'? -> It processes the input to determine what actions to take next. So what qualifies as an input? What qualifies as an action? How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? What's happening there is just a physical interaction of the 'inputs' interacting with the system. So? See my last point. How is that information related to the meaning of the information - how does that work? If the brain is just computation, how does the "semantic information" in the brain work? -> What is "meaning of the information"? What is "semantic information"? Information informs about certain details, a system can take the information and understand its meaning. 'semantic information' - sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process.

kd0amg 15y ago
So what qualifies as an input? That which affects the system What qualifies as an action? Changes in the system's internal state or output How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? You can test whether its state changes in response to external stimuli (n.b. this is no way to test this perfectly). See my last point. Looking back, it seems like you think I've made some claim about the system having "learned" something. Information informs about certain details, a system can take the information and understand its meaning. I agree that a system which computes can take the information and act in a way that depends on it, but what do you mean by "understand"? sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process. This is not a definition of either term I asked about.
- jamesrcole 15y ago
  So what qualifies as an input? -> That which affects the system That applies to any causal interaction with the system. What do you mean by 'system'? How do you objectively determine whether some physical details are a 'system'? What qualifies as an action? -> Changes in the system's internal state or output Same kinds of issues. What is the objective criteria for 'system', 'internal state', 'output'? What are the relevant sorts of 'changes' - there's all sorts of physical changes that are not relevant. How do you tell if some physical system, e.g. some biological system, contains 'inputs' and 'actions'? -> You can test whether its state changes in response to external stimuli (n.b. this is no way to test this perfectly). but you need some objective criteria for what changes count as stimuli and what are just "meaningless" interactions with the system. Information informs about certain details, a system can take the information and understand its meaning. -> I agree that a system which computes can take the information and act in a way that depends on it, but what do you mean by "understand"? Act in a way that is appropriate to what the information is about. and btw this is an imprecise and vague description of 'understand'. a proper theoretical account would be a lot more precise. sometimes people use this notion to distinguish between 'data' and 'information' that is more meaningful, like the sort of information that humans can process. -> This is not a definition of either term I asked about. these aren't my terms/notions. if you really want to know what people mean by them there's stuff online.
  - kd0amg 15y ago
    Pretty much anything can be considered as a "system," any aspect of it its "internal state," any aspect of it which can affect something else its "output," and any phenomenon that can affect it as "input" or "stimulus" (there is no need for any of these to have any higher "meaning"). The fundamental problem here is that any definition broad enough to encompass everything that can be considered "computation" is going to be too broad to say anything meaningful about the nature of the class of phenomena it describes. Yes, asking what the nature of computation is requires a definition of computation in order to be a well-posed question, but the whole song and dance then reduces to asking about the nature of things that fit some chosen definition (and any definition suffices for playing that game). If you want to learn anything substantial, you'll generally have to pick some particular model of computation to study. You could choose to study deterministic pushdown automata, and then you will learn about computation that fits in that model. Or you could study Markov algorithms and learn about computation that fits in that model. Or you could even study something like Turing machines augmented with halting oracles. For computers that fit a particular model, you can discover things like what they can and can't compute, how quickly they can compute various things, what it takes to convert a computation system defined in that model into another model, etc., and this will all follow from properties of the model you've chosen to study. The only thing common to all models is that they have some way of mapping "input" to "output" via some change in "state." That is not specific enough to draw much further insight, so computation theory tends to talk about particular sets of models (e.g. "anything equivalent to a Turing machine").