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Author | Topic: The value of Gitt information | |||||||||||||||||||||||||||
Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
For now, I'll offer this hint: I'm suggesting that DNA transcription is, ultimately, as deterministic a process as is a rock rolling down a hill. I'm not sure it is transcription that is the relevant point when we are talking about the origin of the information within DNA, if there is any. TTFN, WK
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Percy Member Posts: 22499 From: New Hampshire Joined: Member Rating: 4.9 |
Cal writes: Well, if we want to be really pedantic, the strictest possible interpretation of Gitt might be said to include the implication that information (which cannot exist without a code, transmitter, etc) isn't actually information when it isn't being encoded, transmitted, or decoded. What it is the rest of the time, I can't imagine. I wasn't saying anything about Gitt information. I don't know that a consistent and valid interpretation of it is possible - Gitt information seems to me just a bunch of unsupported assertions. The context of my reply was the encoding and decoding of Shannon information.
Actually, information is one of a set of messages that you wish to communicate. Apologies for not finding that very... well, informative. "Wish" seems to be the key word there. The principle that you find uninformative is at the core of Shannon information. This is from the 2nd paragraph of Shannon's original paper:
Shannon writes: The significant aspect is that the actual message is one selected from a set of possible messages. Moving on:
Cal writes: I guess the whole metaphor must not have worked for you then. I don't have time to unpack it fully right now; maybe this evening. For now, I'll offer this hint: I'm suggesting that DNA transcription is, ultimately, as deterministic a process as is a rock rolling down a hill. I think just your saying this clarifies your meaning, which at heart is about making an interpretation of which constitutes signal and which noise. But that involves assigning meaning, which as Shannon correctly states, is irrelevant to the engineering problem. Once you've made your choices about what constitutes signal and noise, then you can begin solving the information engineering problem. --Percy
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Cal Inactive Member |
WK writes:
Agreed. Haste is my excuse. "Transcription and translation" would have been better.
I'm not sure it is transcription that is the relevant point when we are talking about the origin of the information within DNA, if there is any. Percy writes:
Oh, sorry. I guess I let the thread's title lead me astray.
I wasn't saying anything about Gitt information. Percy writes:
There's always going to be a teleological referent, which (again) is precisely my point. Here, it is the word: "selected". "As in natural selection?" (did I hear you say?) Yes, but remember, the term "natural selection" is a metaphor; no entity is required to make the choices, the choices make themselves. I stand by my claim that Shannon -- by the very act of explicitly excluding semantics from his model -- implicitly acknowledges the existence of some entity or entities with the capacity to find "meaning" (hopeless to define anyway) in symbols. If I axed you to relay a message for me, and it contained sum miss pelled words, would you have a reilable way of knowing whether those apparunt errors were kritical to the meaning of the "aksuall message"?
The principle that you find uninformative is at the core of Shannon information.[from the 2nd paragraph of Shannon's original paper]: The significant aspect is that the actual message is one selected from a set of possible messages. Percy writes:
Meaning isn't merely irrelevant to Shannon's purpose. It is assumed that among the set of all possible messages exists one which is the most meaningful, but it is not only unnecessary to choose between them on that basis, it is absolutely imperative that no attempt be made to do so; the message must be considered to have been at its maximum fidelity at the signal end.
I think just your saying this clarifies your meaning, which at heart is about making an interpretation of which constitutes signal and which noise. But that involves assigning meaning, which as Shannon correctly states, is irrelevant to the engineering problem. Once you've made your choices about what constitutes signal and noise, then you can begin solving the information engineering problem. Edited by Cal, : No reason given.
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Percy Member Posts: 22499 From: New Hampshire Joined: Member Rating: 4.9 |
Cal writes: Percy writes: I wasn't saying anything about Gitt information. Oh, sorry. I guess I let the thread's title lead me astray. Well, now I'm confused. Are you saying that when you wrote this in Message 13:
Cal in Message 13 writes: My problem is in the circular way "information" is defined: What is a code? That which contains information.What is information? That which is represented by a code. What is DNA? Coded information. That you were talking about a problem with Gitt information, not Shannon information? It was written in response to a paragraph from WK about Shannon information.
If I axed you to relay a message for me, and it contained sum miss pelled words, would you have a reilable way of knowing whether those apparunt errors were kritical to the meaning of the "aksuall message"? Yes, of course, but that's because of redundancy. The correct letters are only one of the many cues for the correct information.
Meaning isn't merely irrelevant to Shannon's purpose. It is assumed that among the set of all possible messages exists one which is the most meaningful,... No, this is not assumed. As Shannon correctly states, meaning is irrelevant to the engineering problem.
...but it is not only unnecessary to choose between them on that basis, it is absolutely imperative that no attempt be made to do so; the message must be considered to have been at its maximum fidelity at the signal end. My guess is that you're making the mistake of thinking that communicating information in the presence of noise is somehow associated with meaning. If an encoding of information contains insufficient redundancy such that after transmission through a noisy medium it is ambiguous which message from the set was originally sent, selecting a message from the set based upon some criteria is not an exercise where meaning has any role. --Percy
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Cal writes: I stand by my claim that Shannon -- by the very act of explicitly excluding semantics from his model -- implicitly acknowledges the existence of some entity or entities with the capacity to find "meaning" (hopeless to define anyway) in symbols. But that isn't what you claimed, you claimed that Shannon made ...
Cal writes: ... the tacit assumption that the message originated with an intelligent source which is quite distinct from acknowledging that entities exist which can ascribe meaning to symbols. After all the reciever alone can ascribe meaning to the symbols they receive, and I might suggest that is what is happening in this case. We can find shannon information in DNA but the meaning we attach to it is our own interpretation and understanding of its physico-chemical function. And if we remove the neccessity for intelligence at the source then natural selection is a perfectly valid mechanism for 'selecting' a specific message from all the possible messages. TTFN, WK Edited by Wounded King, : No reason given.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Agreed. Haste is my excuse. "Transcription and translation" would have been better. Again I would disagree. Transcription and translation are the appropriate stages if we are looking at the transmission of information from the genome being used to 'inform' the synthesis of proteins but not if we are interested in the origin of the information in the genome itself. For that we surely have to look at mutation and natural selection. TTFN, WK
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Percy Member Posts: 22499 From: New Hampshire Joined: Member Rating: 4.9 |
I think Message 20 from WK was intended as a response to you, not me.
--Percy
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Oops, sorry Percy.
TTFN, WK Edited by Wounded King, : No reason given.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Just to bring this up again since the topic has arisen in Ned's thread.
TTFN, WK
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