- Russell Standish wrote:
> Information is never negative. However, information is not additive -

I don't think I_{1,2} can be >= I_1 + I_2, so I_{1+2} cannot be zero as

> ie if there are two systems with information contents I_1 and I_2, the

> combined information I_{1+2} differs in general from

> I_1+I_2. Therefore it is possible to have I_{1+2}=0 with I_1>0 and

> I_2>0.

>

> (From memory the information formula can be expressed as sopmething

> like:

>

> I_{1+2} = I_1 + I_2 - I_{1,2}

>

> where the last term is joint information)

far as I understand it. (Look at the two limiting cases where the

processes are independent or fully correlated.) In fact I don't think

I_{1+2} can be < either I_1 or I_2. But I could easily be wrong; I'm

not an expert on this stuff.

-- Gary >Well, if the universe contained nothing but two 'apples' of the same size

No. That's just an artefact of a definition. A play with mathematical

>and mass - yet one apple was made of matter and the other, identical apple

>made of anti-matter, then you would have two apples. But the 'net' result is

>that the universe actually contains no matter (or antimatter) -no?

concepts. Certainly a reality containing nothing is a different one from

one containing an apple plus an anti-apple. For information it makes even

less sense to talk about negative information.

[Non-text portions of this message have been removed]- In a message dated 12/30/2002 6:53:19 PM GMT Standard Time,

brhall@... writes:

> Well, if the universe contained nothing but two 'apples' of the same size

Depends if you consider photons to be matter, I suppose.

> and mass - yet one apple was made of matter and the other, identical apple

> made of anti-matter, then you would have two apples. But the 'net' result

> is

> that the universe actually contains no matter (or antimatter) -no?

>

> I'm still yet to fully understand the notion that the multiverse contains

I *think* the idea is that "all possible information" is like white noise -

> zero net information, so these analogies are groping in the dark, I know.

> Who is it who argues for this theory, and for what purpose? I seem to

> recall

> some posts which allude to the idea.

you can't actually get any information out of it unless you know that it

contains a message, and what the compression code is, and so on ("any

sufficiently advanced communications look like white noise" - Clarke's Nth

law?) Or something like that. A bit like this email perhaps....

If you could put together all possible information - say every possible book

(e.g. in "The Library of Babel") then *somewhere* you have every book that

will ever be written (in any universe) or ever COULD be written. If you put

together every physically possible universe then you have the multiverse.

Does the thing as a whole contain any information? I don't know, but I don't

see how it's meaningful to say that it does because there's no way to extract

the information, or do anything with it.

Hm, I need to think about this some more.....

:-)

Charles

[Non-text portions of this message have been removed]