Tuesday, June 03, 2008



Fuzzy logic of human language and evolution

Fuzzy logic is now a big deal in mathematics, in engineering, but I perceive fuzzy logic as typically human system of logic. It might be even possible that fuzzy logic is innate to all biological organisms not only to humans.

Let’s start with the fuzzy logic in the human language and human logic. Usually, you do not say to somebody sitting next to you on a couch: “Move 15 inches closer to me.” What we usually say instead is. “Move a bit closer to me.” But the same sentence can be used with totally different contexts. First, you just want to make place for the third person coming to take place on that couch. In the second case it is a sentence that a female can say to a male when desiring sexual relationship and body contact, whereas in the first case the body contact is not permitted.

When comparing these two cases we can see that there is seemingly no fixed point that would perfectly explain that the word “bit” means, as it means in both cases something else. But there is a common point; it is the fact that the speaker knows that the other person knows in what situation the sentence is said. In the first case, both persons already sitting on the couch see the third person coming and wanting to take place. Both of these people can see the person, they can see how is the place meant for sitting on the couch divided and how it must be changed so that the third person can take place there too. In the second case both the female and the male know in what situation they are and that the moment of physical contact is approaching, they also now there is nobody around and that they both would like to have sex.

So fuzzy logic is actually logic based on the fact that the other person or persons know in what situation they are and what exactly the imprecise sentence means. Fuzzy logic is the logic based on relation to the situation, to the status quo, and also based on the prediction of what is going to happen and what must be done that it this predicted future is permitted or prohibited by one’s own behavior.

Using the two examples described before, if the male would not like to have sex with the female, then he would not move as close as to touch her and have body contact with her, but only a “bit” so that he does not touch her and he would not permit the body contact. In the “couch” case if I do not want to permit that the third person comes and takes place on the couch as well, I just move too little so that there is still not place enough for the third person to take place.

In opposite cases the male moves as close as possible so that their both bodies come to direct contact and one person on the couch moves so much aside, so that there is enough space for the third person to take place.

Especially in the “couch” case, the person that moves can decide to move in two direction, either the person moves away from the person already sitting there, so that the third person can take place between them two, or, this person can move closer to the person that is already sitting there, so that the third person must sit at the other end of the couch. This is then already psychology, as the person that moves can decide whether the third person will sit in the middle or at the edge. Sitting at the edge can mean being “expelled” from talking as the first two will speak to each other and the third person sits away from the discussion place. If the person to move permits the third person to sit in the middle that it can be explained as not wanting to sit next to the first person, or it can mean high esteem for the third person as sitting in the middle gives this person both options open with whom the person wants to talk, or if the third person wants to talk with both persons sitting there already before.

Most probably this fuzzy logic is also the basis of evolution; it only permits for some changes based on the already “known” or presently existing situation. A cell being exposed to some informational input from its environment “knows” its present state and also “knows” how many times this signal has appeared before and acts accordingly in a fuzzy type of logical action. It permits only for “a bit” of a change. Actually, the evolutionary development of eye presented by Dawkins shows exactly this step by step fuzzy revolutionary development.

In human language there are incredibly many “fuzzy” actions or reactions and they are always based on the fact that the other person or persons is or are familiar with the situation to which the fuzzy remark is linked to.

Just imagine winter and you are heating and the other person says:”It is too warm for me.” It is perfectly fuzzy statement as it does not says by how many grades it is too warm. So you cannot know exactly by how many grades you should decrease the temperature. You must try or you already know the person and you know what the usual temperature is the person likes, e.g. your wife.

There are many other examples where we go “fuzzy”. For example, when we start to learn basketball, there is no way of your trainer telling you that you should throw the ball under some exact angle and use specific force of 2.5Nm, even when he did, most probably you would not understand.

When driving a car you never compute the formulas of speeding up when passing a truck or formulas of decelerating when you try to slow down, we do it in the fuzzy way, constantly comparing to the other stuff in the given situation. When accelerating you may decide to press the gas pedal more if you “feel” that the speeding up is to slow for safe passing. On the other hand you may “feel” that the slower speed is still to high as you cannot read all the names of the streets in an unknown town.

Fuzzy logic is the logic of constant comparing and constant adjusting to the situation that has changed based upon one’s own action or the action of somebody else: like new person coming and wanting to take place on the couch.

When speaking about something that changes the situation like no electricity suddenly or some accident on the road or some rock avalanche we have the problem of determining whether the author of this action is another human, animal or a thing. A supernova explosion is definitely not caused by human beings, but snow avalanche can be. The increase in the activity of sun is also definitely not caused by humans. So we can have really different authors of a changed situation: humans, animals, and non-living entities.
It really doe not matter at all who is the other of the change in situation that we perceive but we always react in a fuzzy way as that is the way the whole evolution has happened.
Even some jobs are based on fuzzy actions; anytime you have something repaired where the flaw in the system is not obvious the repair person must try.

This system of trying is normal in computer repairs, car repairs, but the car industry seeks to get rid of this uncertainness and places many sensors into the car system and it is then possible to “ask” the car :”What is wrong with you?” using some computer capable of reading the signals of the sensors in the car.
One might think of many other systems that function as fuzzy systems, but humans and their means of communication, the language is the best one. Just think of notes like: I’ll be back soon.”, “Wait a moment.”, “Go little bit more to the right.” and many other examples.

I believe that that what we call fuzzy logic is actually the normal logic based on the one’s own situation or upon the fact that we know that the other person knows that we know etc. I also strongly believe that this way of thinking is basic for all organisms, to start with a simple cell, and most probably some changes in DNA might be fuzzy logic driven. The reason for this might be the fact that the nature uses the system that has approved. That means we are using system that has been approved through millions of years. And if it so then, of course, the fuzzy logic must be seen also in other systems not only in humans. I believe animals also use fuzzy logic, as well as cells.

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