Information about information

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We live in a golden age of information. Never has so much of it been available so easily to so many of us. Information is power, it's money and, given how much of our life is lived online, defines part of our reality.

But what exactly is information? We tend to think of it as human made, but since we're all a result of our DNA sequence, perhaps we should think of humans as being made of information. We like to think of it as abstract, but there's no information without physical manifestation, be it in the neurons in our brains, the pages of a book, or the electrical circuits in a computer. We like to think of it as floating on top of reality like a cork on an ocean, but insights from quantum physics suggest that reality might itself be made up of it. Perhaps we do live in a matrix after all.

In this project, brought to you in collaboration with FQXi, we'd like to take you on a journey through the fascinating world of information. But we'd like you to tell us what you'd like to know about information. To start you off we've chosen a few key questions philosophers, physicists and mathematicians are currently thinking about. There's a little background on each of them below, and a poll on the right in which you can choose your favourite one. At regular time periods we'll put the most popular question to the world's leading experts and come back to you with their answers. If you've got a question that's not on our list then please let us know by posting a comment below.

The question that won the first poll is "Can information be turned into energy?". Here is the answer, based on an interview with MIT physicist Seth Lloyd.

Is there a universal language of information?

When NASA launched the Pioneer spacecrafts in the 1970s it equipped them with plaques showing the nude figures of a man and a woman, a schematic representation of the solar system, as well as other drawings designed to impart information to aliens that might intercept the crafts. Whether or not alien life forms could actually make sense of these is debatable. Is it possible at all to develop a language that every intelligent being is sure to understand?

Are there fundamental laws of information processing?

It seems that computers double their processing power roughly every two years. So reliable is that rate of increase that it's got its own name: Moore's law, named after Gordon Moore, a co-founder of Intel. Of course, Moore's law is not a law in the same way as, say, Newton's laws of motion are. The latter are a features of reality, while Moore's law is just an accidental pattern in human made activity. Or is it? More generally, is information processing subject to fundamental laws that can't be broken? Are there ultimate limits on information storage and processing power? Could such laws be used to predict the future or figure out what super-advanced civilisations might be doing elsewhere in the galaxy?

Is the world made up of information?

It's tempting to think of information as something that describes the physical world around us. However, since the end of the nineteenth century we have known that that physical world is not as solid as it may seem. Tiny particles of matter, such as electrons, can be in several places at once, they behave like waves in some situations and like particles in others, and they can also exhibit a range of other properties we'd normally deem mutually exclusive. The reason why we never see this superposition happening is that as soon as we perform an experiment to measure, for example, where an electron is, this strange superposition of states seems to collapse to give just one definite outcome. We can't say with certainty which outcome that will be, although we can compute the probabilities that we'll observe a particular one (see this article for more information).

This is the central message, as well as riddle, of quantum mechanics. It suggests a new way of looking at reality: since what we actually experience depends on us observing the world (via our measuring devices), reality is shaped by answers to yes/no questions. For example, is the electron here or is it not? Is its spin pointing up or pointing down? Answers to questions are information — the yes and no in English language correspond to the 0 and 1 in computer language. Thus, information is fundamental to physical reality. As the famous physicist John Archibald Wheeler put it, the "It" we observe around us comes from the "Bit" that encodes information: "It from bit". Is this really true?

What is quantum information?

The conventional computer you're looking at right now works with bits: little units of information that can be either 0 or 1. In the murky world of quantum mechanics, however, information could be held in systems that are in superposition, taking several values simultaneously. How exactly do we define such quantum information? What are the rules that govern it? And what light does it shed on the power and scope of quantum computing?

Can information be destroyed?

What happens to a book when you burn it? For all practical purposes its content is lost to the world. In theory, though, it is possible to reconstruct the book from its ashes and smoke — it's not impossible for the burning process to be reversed, it's just highly unlikely. In that sense information is never lost. That's indeed one of the basic tenets of quantum mechanics. In the 1970s, however, Stephen Hawking and Jacob Bekenstein came up with an argument which suggested that information can be gobbled up by black holes. Their prediction split the physics community and led to the "black hole war" between Hawking and his colleagues. So what exactly is this black hole information paradox and can it be resolved?
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Comments

QUESTION: What Is the Relationship Between Entropy and Info?

I'd like to have more on the relationship between Entropy and Information. On first blush, they seem like opposites. More entropy, more chaos and disorder; more information, more order and regularity. And yet, I have read more and more about the relation between certain interpretations of information and entropy, how a lot of complex stored information will raise the entropy of the medium storing that info. But does it work the other way? If a gridboard of black and white squares (digital, 1 or 0) has a high entropy (pretty mixed up in appearance, nothing all that different between one section and another), is there necessarily information behind the way those squares are? Maybe I'm asking, does information have to be "informative" to be information? If you take the word in syllables, you get IN -- FORM -- ATION. Implying that something is being formed from within. Implying that information is relative, if the tree falls in the forest and nothing else is there to be informed about it . . .

Oh, and then there is all that stuff about black holes and entropy and information, how the info that went into a black hole is proportional to the surface area of the black hole horizon and not the volume . . . cool stuff, but what is it all pointing to? Just what do they mean by "info", when a book falls into a black hole? Is it just the quantum state of every particle in the book, or does it include the letters and words and numbers on the book pages, the size of the pages, the thickness of the cover, etc? Thx, JIM G.

Fisher Information

I've heard of fisher information before-- I don't really understand it, but apparently Fisher does! Here's the introduction on the website, followed by the link:
Enjoy!

Over the past 15 or so years, it has become increasingly clear that the fundamental laws of science are expressions of the concept of information. This includes laws governing the small (at subatomic scales), the large (astronomical scales), and everything in between. In between are chemistry, biology and even higher-level effects involving willful human activity, such as economics and sociocultural organization. These laws all derive from a principle of information optimization called extreme physical information, or EPI.*

*Although long in coming, the EPI principle has only recently been derived. (See Sec. 9, Recent Papers). This is in the paper by Frieden and Gatenby,"Principle of maximum Fisher information from Hardy's axioms applied to statistical systems," Phys. Rev. E 88, 042144 (2013), 6 pages. This shows that EPI follows from the very mathematical axioms that are the basis for all known physics. A sketch of the derivation is in Section 4.

http://fp.optics.arizona.edu/frieden/fisher_information.htm

information

Our consciousness is like a wormhole that can reach out to every bit of information in the past perhaps once we can also reach out to the future and leave our causal life-line.
Wilhelmus

Is the world made up of information?

I have been thinking that what is important is the "extraction" of information from the universe. We extract information via some sort of measuring device - be it our own eyes or high tech devices to peer into the very small or very large. This is what I take from Wheeler's "It from Bit"

That red chair we see - is it anything more than an artefact formed by our brains based on the information we receive via our retinas?

When we try to "see" which hole the electron went through in the double slit experiment - we extract information from the system under consideration, hence forever changing the system under consideration. We pump energy into the system (measurement) and get information in return.

QM suggests that prior to our extraction, the electron exists in a superimposed state - and the extraction causes the "collapse of the wave function" and we see the electron at one slit or another. The state of the electron went from probability to certainty - due to the extraction. Taking something from a system usually means the system changes - yet taking information usually seems sort of "soft" - yet things like position, momentum, charge, spin, etc. can only be known by information extraction. But by "known" - what do we mean? Sometimes we mean that something gets stored in a storage device - be it a computing storage device or a human brain. I think Bohr suggested this at least meant "registration" - like the trail of a charged particle through a cloud chamber or a piece of crystal (not necessarily a conscious human brain). Registration usually means exchange of energy leaving behind information about the event.

Being educated in Physics yet spending a lifetime in Information Technology - I find it fascinating there may be convergence of these technologies - and indeed the universe may indeed be made up of information.

What is thought??

I think that the real question that must be asked is, "What is thought?

Is thought energy and can it be captured?? I believe that though is energy and that it can be captured. Most prevalent example of this information that can be shared between people who love each other or share strong relationships. It is not a coincidence that people who work in teams "know" what team members are thinking, nor is it a coincidence that mothers can be awoken at night when tragedy may befall one of their children that may have occurred 1,000s of kilometres away.

So if thought is energy, then information cannot be destroyed!! However what is the point of information if it cannot be communicated or transferred/captured to another person?? It is like giving me a scientific journal that is written in Icelandic. However I can learn Icelandic over a decade and therefore it is possible for that information to become useful. With thought you get one shot!!! Unless we have the learn the ability to capture someone's thought, then travel at a speed faster than the speed of thought to a point where we can get a second chance to absorb and decrypt that thought, then that thought becomes as pointless as a deaf person speaking in a soundproof room.

The example of burning a book as the destruction of information is quite childish, and the use of quantum physics to reassemble the book from the resultant ash, carbon dioxide and water is ludicrous. At least you could have been a little historical and spoke of Babylonian text on a clay tablet that is smashed, or given it some modern day relevance with a computer magnetic memory passing through an intense magnetic field.

But what about the killing of a person!!! And with their death, the killing of their thoughts and ideas!!! Isn't that the basic notion and outcome of political assassination??? The destruction of ideas and thought??? But in today's world we often do not have to kill a person to kill the the thought, governments and media simply bombard us with other ideas and thoughts that are contrary to how they do not want us to think. And the thought is lost or unheard.

Information is merely thought that is recorded/captured in a manner that may be transferred to another persons consciousness at a later time. It is the original thought that is important.

Information & the philosophy of mathematics

The ancient debate between Platonists and Aristotelians, it seems to me, is germane to this topic. Platonists would argue that information transcends human minds and material reality but is still real. Aristotelians would agree that it is real but see it as a property of material things. The idea that somehow the world *is* information seems to assume Aristotelianism. But what if Plato was right? How would that affect the nature of these investigations?

Information

I think all your information questions are interesting.

I would like to pose a couple of related ones:
"Is information part of the material world?"
"Is information subject to the laws of physics?"

QUANTUM COMPUTING

Will quantum computing facilitate artificial intelligence? How far into the future before that becomes a reality; 10 - 15 - 20 years? And, what does AI mean for us - the end of humanity? "Will we dream, HAL?".,
James ( Jim ) Oss
Wa Keeney, Kansas USA
jamesoss@gmail.com

you're missing the woods for

you're missing the woods for the trees: what role does the (architectural?) ambience of a place like Cambridge play in creating the best maths environment in the world? that ambience creates this website which allows you to pose this question about physics and cosmology in the first place.

Can information ... etc.

One answer might answer another question. e.g. 'can info be turned into energy'? If yes then it tells us that info cannot be destroyed ... etc.