The cart pulls the horse

Luís Ángel Fernández Hermana - @luisangelfh
12 December, 2017
Editorial: 157
Fecha de publicación original: 2 marzo, 1999

Where there is suspicion, there is caution

Fisher Information” is not a key piece of information that belongs to this gentleman. Quite the opposite in fact. It is the information that is missing from our understanding of how things work. And, according to Fisher, in all the systems that surround us that information deficit exists and despite this fact we make laws about how the universe, our world and even our virtual worlds work. And, apparently, they work. Which is a mystery even greater than those the Vatican subscribes to. Unless there is a mistake, either in Mr Fisher’s concept or in the way that we understand nature and decide the way it works via fundamental laws that is. And, it is this that Roy Frieden suggests in a book which is bound to shake the cosmogony of science at the turn of this century and fairly far beyond. In “Physics from Fisher Information, a Unification” (Cambridge University Press), Frieden suggests that all attempts to extract information from nature determine the answers we get. Which, if true, makes for an interesting vision of the world we live in where information is becoming the omnipresent monarch of a society submitted to its rule.

Ronald Aylmer Fisher was a statistician at Cambridge who, some time in the 1920’s, noticed a small but fundamental thing: no matter how hard we try, we can never obtain all the information we want about a particular system. Or, to put it another way, all the information to be obtained from a physical system is so-called “Fisher Information”, which despite not being complete — or fully explaining — the system, is used to make laws about the way it works. Logically enough, we never find out where that law comes from and, even less so, why the devil it works. Nevertheless, it is on this disparity that all laws from electromagnetism to gravity, through particle physics, gases, and, of course the birth of the Universe, space/time and, to cut a long story short, ourselves, are based.
We do not know if Fisher came to this conclusion after long reflection on the innate tendencies in human nature towards making mistakes, although, it is almost certain that it was his well-known experience as a statistician that put him on the road to this essential piece of information. No matter how he got there, Fisher realised that all phenomena, all systems, all natural events contain a determinate amount of information and that our efforts to acquire this are prone to errors. For a start, there is always a margin of error in measuring and observation equipment in addition to the inherent errors of the system itself, such as transitory chaotic phases induced by internal or external changes or, something we all know only too well, jolts caused by the observation process itself. In other words, nature is not very inclined to let us find out all there is to know about her and we only manage to understand a part, however sizeable that might be, of all there is to know.

Using this as his point of departure, Frieden came to the conclusion that, according to him, put him on the road to discovery of the Mother of all Laws, in other words, that which could explain where the laws of physics that “govern us” come from. This renowned researcher from the Optical Sciences Center at the University of Arizona, thinks that every physical phenomenon occurs in reaction to how we measure it, or in other words, it acts as a catalyst for the effect obtained. To put it another way, laws of physics are no more than the answers to questions posed. Consequently, information precedes the world that we are discovering, which, in turn, does not necessarily correspond to the information we possess to describe it. This, if true, is very interesting.

Nature has a peculiar inclination for producing action. And scientists follow this inclination by being incessantly on the look out for them. No sooner is a fundamental law of physics discovered, for example, than a race to discover the specific action necessary to corroborate its functioning begins. But nobody really knows for sure why nature is so concerned with actions. For the same reason, nobody can get to them and establish them directly without observing them. The only methodology at hand is to backtrack over the steps of the law, once it has been discovered, to find the actions that verify its functioning. This path, although the most well-worn, does not appear to be the most recommendable.

Frieden, who has spent more than twenty years cleaning up blurry images in order to extract the maximum amount of information from them, everything from galaxies to car licence plates, has turned this method around and suggested that the most important thing is not the action we are trying to discover, but the best description we are able to make of it. We know that the information for this description exists and we want to extract the most possible about it from our measurements and observations. We want the difference between what we obtain and that which the system possesses, to be as small as possible. When we consider that we have reached the optimum point in this process, we call it a law of physics and determine that this is the way nature works. However, in reality, the attempt to extract the information has determined the answer we have got. So, as some outstanding thinkers in the XVII century maintained, the participation of the observer creates information and the information creates physics.

Frieden’s ideas are beginning to gain ground in the scientific community, although predictably slowly given the modification of existing paradigms it implies. Nevertheless, his attempt to explain the origin of the laws of physics has come at a very opportune moment, just when information is starting to occupy the epicentre of a society which tries to explain itself through the information it self-generates. And, along the same lines, we know quite a lot about the close relationship between action and the information that tries to back it up. In the light of Frieden’s ideas, we should be extremely careful about what goes before, the cart or the horse, the effect or the cause, the bit or the fact.

Translation: Bridget King.