26 April 2007

When is information not information?

As a child I often grappled (as, no doubt, did you) with the question of whether space ever ends or whether it goes on forever. Common sense told me that nothing goes on for ever ... so there had to be an end. But when I tried to visualise that end, it always took the form of a barrier of some kind ... and common sense told me that the barrier must have another side ... and something beyond it.

Then, of course, as I grew, I discovered that not every question has a clear-cut answer ... and that, as questions get further from common experience and human scale, so common sense becomes less reliable as a guide.

I found myself running in similar mental circles, three weeks ago, around the mulberry bush of Jim Putnam's question of whether or not Dr C can refer to "information" being transferred between eye and brain. (Alas, other events in life prevented me from addressing the issue in here until now.) And the unsatisfactory answer for which I've eventually had to settle is the same one which I would now have to offer my childhood self over the finiteness of space: it depends on your point of view, your frame of reference, and your definition of terms.

Dr C takes the straightforward view and concedes the point: that whatever is transferred is not information until used by the brain. It's not a simple as that, however.

First, Dr C points out that some information processing takes place before the pulses are despatched down the optic nerve. What leaves the eye, whether information or not, is "signal". Now ... if I codify and transmit a signal with intent to communicate (for instance, I write this post and despatch it to the web server), does that signal constitute information?

Each word is what linguists call an "arbitrary signifier". Each character in the word is, in its turn, an arbitrarily assigned symbol representing a sound or other structural communicative component. And each character is, in turn, replaced for digital transmission purposes by an arbitrarily assigned bundle of electronic bits. But the precise combination of bits which leaves me, and reaches you, is not random: it is designed (by me, by human cultural history, by digital coding agreements) to enable my verbiage to arrive in front of your eyes for reading as they did before mine as I wrote. If the result is not information, perhaps it should be described as "potential information".

The same is true of signal passed from the retina along the optic nerve to the brain.

But, secondly, I am not convinced that we can really speak of an information (or potential information) carrying signal being passed between eye and brain, in the same way as it is between you and I. In a cybernetic sense, the eye and brain are not discrete units; they are, to at least some degree, parts of a single integrated system; in some ways, the eye is part of the brain. Nor is the brain itself (disregarding the eye) really a single entity; it is a collection of (in many ways partially autonomous) parts. Given all of this, the whole question of information, or impulses, or signal passing between eye and brain is a fraught one - at the same time both true and untrue in complex combinations.

Then again, the universe is probably nothing but information anyway; I, my brain, my eye, are all nothing but small information structures within a larger sea of it.

Having thoroughly confused myself, I shall now go to bed.

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