mind, matter, meaning and information

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physical information

Information” is very closely related to “form,” and form is what separate but similar physical objects share. Form is very different from substance, or matter: a certain shape, for instance, can occur in more than one place at one time. However many copies of an item of form or information exist, it remains one single item. This is its “numerical identity”.

The numerical identity of physical objects only allows each to occupy one place at one time—if they're in more than one place, there's more than one object. But Mozart wrote an opera called The Marriage of Figaro, no matter how often it has been produced. Every production is slightly different, but these are considered versions of the same opera, rather than different operas, due to what they have in common: the information they share. A particular performance of it remains just that—a particular performance—even if it was recorded, and thousands of CD's made.

It was once reported that, while someone was threatening to sell the secret recipe for Coca Cola to the highest bidder, a company representative claimed it was actually secure in the safe at headquarters—apparently confusing the recipe itself—the information—with the paper it was written on.

Form is most often thought of as shape: we might say that any two coins of the same denomination have the same form, meaning they are of the same thickness and diameter, with the same or very similar decorations. But they also weigh about the same and have roughly the same electrical resistance, and these specifications are equally important characteristics of the coins.

Physical information is a generalisation of the usual concept of form, covering any quality of matter that can be determined by any kind of experiment, and that might be shared with other material things: shape, size, weight, colour, electrical resistance, chemical composition and so on. Think of an experiment as a kind of interrogation, intended to extract information from its subject. This is what we are interested in.

Physical information is basically the form, or structure, of physical things. The advantage to physicists of considering form/structure as information is that they can use mathematical techniques on it. An example is the relationship between physical information and entropy.

According to Roy Frieden, the laws of physics are generated by the attempt to minimize the difference between an entity or system's own, physical information, and the information that physicists can obtain about it. This account does not get awfully technical, at least as regards physics—we've just gone as deep into Frieden's work as we're going to go—but this distinction he draws is vital: between physical information, which exists for its own sake, and the more usual sort, information that's about something.

To view physical structures in terms of information is to see every object as embodying its own description. Any information we might have about the object has that intrinsic description as its ultimate source and refers back to it. The physical information is the ideal, the absolutely perfect description. While other descriptions can approach it, in terms of accuracy and completeness, they can never quite reach it. See subjective and objective information.

Information, or form, might be “just” an aspect of matter. But to think in terms of form rather than those of substance is a winning strategy in many situations—even in physics, never mind communications, computation, etc. Following Daniel Dennett, this strategy can be called “the formal stance”.

The formal stance can be taken not only towards static physical structures and energy flow/causation, but also any physical process. Information processing is not a special sort of operation, but just an aspect of any physical process. (Though some are, obviously, more usefully viewed that way than others.) When we take the formal stance towards what would otherwise be seen as a physical process, we see information processing.

Any two entities about to interact can be considered carrier and decoder, while the result of the interaction is the decoded message. There is no reason to confine the concept of physical information to individual entities, and in fact to do so would be inconsistent. The distance between any two entities, say two asteroids orbiting the sun, is an item of physical information, as is the way that distance changes over time. And the outcome of a collision between these things that has not yet occurred but will do so, is physical information too: what will happen in the future is implicit, or encoded, in what is happening now.

Collisions, from the physical stance, correspond perfectly, believe it or not, to en- or decoding operations from the formal stance. Whilst every thing, such as an asteroid, “carries” its own physical information, information also exists implicit in the relationships between different things, even as such relationships change over time: before, during and after an actual interaction. All coded information is a function of the relationship between the carrier and the code as embodied in the decoding mechanism: in effect, it predicts the outcome of the interaction between them. That's what “encoded” means: it describes not a snapshot, the way things are at this instant, but the way they're “smeared” over time: what's happening now with what has happened and what will happen. To say that one thing is encoded in another is to predict that the former will emerge from the latter. The outcome of an asteroid collision is encoded, prior to the actual event, in the characteristics of the asteroids and the relationship between them.

Generalising from that, we get this: the relationship between matter and physical information is such that every material thing, every entity, encodes the outcomes of all of its potential interactions, where the decoding key in each case is its environment at that time.

Information technology is specifically designed to process information, but natural processes such as biological evolution can also be illuminated when we adopt the formal stance towards them.

Physical information is discussed also under subjective and objective information.

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Copyright © 1998--2005 by Robin Faichney. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder. Last modified 26-May-2005 11:52:52 by Robin Faichney.