What's the definition of 'information'?

The Dictionary is always the best resource for definitions. Words become meaningless if we each invent our own definition.

Definition of INFORMATION

1   : the communication or reception of knowledge or intelligence
2   a (1) : knowledge obtained from investigation, study, or instruction (2) : intelligence, news (3) : facts, data
    b : the attribute inherent in and communicated by one of two or more alternative sequences or arrangements of something (as nucleotides in DNA or binary digits in a computer program) that produce specific effects
    c (1) : a signal or character (as in a communication system or computer) representing data
      (2) : something (as a message, experimental data, or a picture) which justifies change in a construct (as a plan or theory) that represents physical or mental experience or another construct
    d : a quantitative measure of the content of information; specifically : a numerical quantity that measures the uncertainty in the outcome of an experiment to be performed
3   : the act of informing against a person
4   : a formal accusation of a crime made by a prosecuting officer as distinguished from an indictment presented by a grand jury

Data

@msbcd If you want personal opinions on what defines information, rather than the actual definition, the Social section is probably your best bet.

I think information theory defines it as something which changes your view on the probability of various states of the world being true.

So, for example: the statement “it is raining” reduces the probability that Billy is playing baseball.
The statement “1+1=2” does not change the probability of any state of the world being true or false (assuming you already know that 1+1=2).

In general, information is a special kind of data:

I recall from my information classes something akin to:

Information is data that influences an agent/system/actor decisions, evaluations or opinions and that is recognizable and processable as such to that agent/system/actor.

So whether data is information can only be judged subjectively from the one the data is information to.

We often refer to our current business environment her in our company as data rich but information poor

Wherever you have something rather than nothing you have information. It is the most basic building block of existence.

@whitenoise I would call that “relevant information” instead of just “information” but maybe that’s too nit-picky.

I was told that information that is not relevant is no information at all.

Relevant information is a pleonasm, in line with “round circle”, “big giant”, “nice Dutchman”.

Bah, sorry, I missed the words “evaluations or opinions” in your original definition.

As long as “evaluations or opinions” is read broadly, I think our two definitions are equivalent.

Everything you know is information, no matter it’s wrong or right

Information is…....
Knowledge decoded /Encoded to suit the perspective of the observer.

We have to assume the existence of a free agent, by which I mean a being that can react to something without beyond physical coercion. For example, if someone throws a ball through a window, this does not impart information to the ball or the window, because they cannot react beyond the direct physical impact. On the other hand, the unlikely occurrence of someone throwing a ball through the window provides information to anyone watching that can cause them to act accordingly.

@whitenoise If your company has loads of data and little information, then it needs to hire someone like me to extract information from that glob of undifferentiated data.
Or maybe you already have such a person, but they aren’t a wizard with Perl. Anyone who is tasked with Practical Extraction of data and Reports thereon should know Perl intimately (those who don’t know Perl all that well use it as a Pathologically Eclectic Rubbish Lister). All of us who use regular expressions frequently recognize our debt to Perl.

Information Theory as linked by @roundsquare above gives a good overview of that particular discipline, but is silent on what “information” means in a physical sense (that is, to the discipline of physics). I will attempt to give an idea of this here, but I will probably get it wrong and hope someone will later correct me. @jerv are you listening?
The basic unit of information is the “bit”. A bit is dimensionless and contains one of two values. In certain physical cases a bit may contain an indeterminate value (either one or zero, not yet determined).
The basic physical unit of information is the event. An event is a point in n-dimensional space at a particular moment in time. Thus events are more complex to describe the more spatial dimensions are used. Also the addition of extra temporal ‘dimensions’ would complicate the definition of an event- but extra temporal definitions are rarely called-for in the physical theories with which I’m familiar.

I prefer to think about information in terms of entropy and complexity. For example, you have some atoms floating in space. These atoms contain certain bits of information—their numbers of protons and neutrons, the spins of their electrons. They are ordered systems which convey discreet signals based on the complexity of those systems. Each nucleus of an atom, each quark in that nucleus, contains discreet bits of information. More importantly, every part of this system—every electron, each electron’s spin and charge—interacts with every other part and it can even interact with stuff outside the system.

Now if all these atoms get sucked into a black hole, that information seems to disappear. All that complexity and all the information it conveys is absorbed into singular properties of the black hole. Black holes don’t have discreet atoms, nuclei, electrons, each with their own spins and charges and whatnot. The entire black hole acts like a single particle; the whole thing has just one mass, spin, and charge, and this is the only information we can glean from a black hole.*

*Hawking radiation implies that the information doesn’t actually vanish into a black hole.

@Qingu According to Susskind and others, all the information that has fallen into the hole is maintained on the surface of the hole’s horizon. Cf. The Black Hole War by Dr. Susskind.
Here’s a video on the subjects covered by the book: My Battle to Make the World Safe for Quantum Mechanics

@koanhead, yeah, I tried to qualify my statement. :) That’s where the idea of holography comes from, right?

@Quingu I didn’t mean to take anything away from your statement except for the implication that information vanishes into a black hole, which you had already repudiated.
I don’t think that the idea of holography actually came from this theory. I think, rather that holography was a happy accident of folks playing around with lasers and photographic plates. I suspect, actually, that the Holographic Theory was inspired by the real-world method of holography rather than vice versa.
I could check Dr. Susskind’s book and tell you for sure (I seem to remember he addresses this idea in the book) but it’s nearly bedtime. If you want me to check, please remind me and I’ll do so.

@koanhead
Thanks for the suggestion, appreciate that. :-)

We actually have a department with a couple of people and two external companies working on processing that glob.

The problem is that we are still learning what to look for. After all, whether data is information is not merely dependent on the data, but also on the agent/actor that should process the information into a decision.

What may be a sunny sky with a couple of clouds to you and me, may be just the information that the Inuit fisherman is waiting for, before he departs on his two day fishing trip.

At school I was taught one of the ways to make a point is to take the data from a source, and make it useful somehow, then it becomes information. Information is useful data.

thanks for the feedback. Interesting to see what you all think :)