It seems backwards to almost everybody. Me too. So much so that this little conundrum pushed me to take a deeper look into information theory.

The key for me was realizing that I.T. is addressing how much information THERE IS in a "situation" (probability distribution) - rather than how much information YOU HAVE (one has) about that situation.

I think Owen is right: taking a look at Shannon's "The Mathematical Theory of Communication" is good. Try to get the edition with the Warren Weaver essay in the front - an essay /about/ Shannon's paper. Weaver talks about the measure in section 2.2 (p. 9 in my copy). He talks in terms of logs of "the number of available choices" rather than inverses of probabilities. Weaver refers to what is being measured as "information".

Most telling, on page 50, Shannon uses the terms "information", "choice" and "uncertainty" in the same breath as being measured by his entropy formula.

Another very good popular-level book is "Decoding Reality: The Universe as Quantum Information [2010]" by Information Theorist Vlatko Vedral. He begins the book with this conversation.

Grant


On 6/6/11 8:17 AM, Owen Densmore wrote:
Nick: Next you are in town, lets read the original Shannon paper together.  
Alas, it is a bit long, but I'm told its a Good Thing To Do.

        -- Owen

On Jun 6, 2011, at 7:44 AM, Nicholas Thompson wrote:

Grant,

This seems backwards to me, but I got properly thrashed for my last few 
postings so I am putting my hat over the wall very carefully here.

I thought……i thought …. the information in a message was the number of bits by 
which the arrival of the message decreased the uncertainty of the receiver.  
So, let’s say you are sitting awaiting the result of a coin toss, and I am on 
the other end of the line flipping the coin.  Before I say “heads” you have 1 
bit of uncertainty; afterwards, you have none.

The reason I am particularly nervous about saying this is that it, of course, 
holds out the possibility of negative information.   Some forms of 
communication, appeasement gestures in animals, for instance, have the effect 
of increasing the range of behaviors likely to occur in the receiver.  This 
would seem to correspond to a negative value for the information calculation.

Nick
From: friam-boun...@redfish.com [mailto:friam-boun...@redfish.com] On Behalf Of 
Grant Holland
Sent: Sunday, June 05, 2011 11:07 PM
To: The Friday Morning Applied Complexity Coffee Group; Steve Smith
Subject: Re: [FRIAM] Quote of the week

Interesting note on "information" and "uncertainty"...

Information is Uncertainty. The two words are synonyms.

Shannon called it "uncertainty", contemporary Information theory calls it 
"information".

It is often thought that the more information there is, the less uncertainty. 
The opposite is the case.

In Information Theory (aka the mathematical theory of communications) , the 
degree of information I(E) - or uncertainty U(E) - of an event is measurable as 
an inverse function of its probability, as follows:

U(E) = I(E) = log( 1/Pr(E) ) = log(1) - log( Pr(E) ) = -log( Pr(E) ).

Considering I(E) as a random variable, Shannon's entropy is, in fact, the first 
moment (or expectation) of I(E). Shannon entropy = exp( I(E) ).

Grant

On 6/5/2011 2:20 PM, Steve Smith wrote:


"Philosophy is to physics as pornography is to sex. It's cheaper, it's easier and 
some people seem to prefer it."

Modern Physics is  contained in Realism which is contained in Metaphysics which 
I contained in all of Philosophy.

I'd be tempted to counter:
"Physics is to Philosophy as the Missionary Position is to the Kama Sutra"

Physics also appeals to Phenomenology and Logic (the branch of Philosophy were 
Mathematics is rooted) and what we can know scientifically is constrained by 
Epistemology (the nature of knowledge) and phenomenology (the nature of 
conscious experience).

It might be fair to say that many (including many of us here) who hold Physics 
up in some exalted position simply dismiss or choose to ignore all the messy 
questions considered by  *the rest of* philosophy.   Even if we think we have 
clear/simple answers to the questions, I do not accept that the questions are 
not worthy of the asking.

The underlying point of the referenced podcast is, in fact, that Physics, or 
Science in general might be rather myopic and limited by it's own viewpoint by 
definition.

  "The more we know, the less we understand."

Philosophy is about understanding, physics is about knowledge first and 
understanding only insomuch as it is a part of natural philosophy.

Or at least this is how my understanding is structured around these matters.

- Steve

On Sun, Jun 5, 2011 at 1:15 PM, Robert Holmes<rob...@holmesacosta.com>  wrote:
> From the BBC's science podcast "The Infinite Monkey Cage":

"Philosophy is to physics as pornography is to sex. It's cheaper, it's easier and 
some people seem to prefer it."

Not to be pedantic, but I suspect that s/he has conflated "philosophy" with "new 
age", as much of science owes itself to philosophy.

marcos

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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org

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