Smart future

look at a heap of sand. Remove a grain from it. Is it nonetheless a heap? Keep on removing grains from it, till what point it's a heap and exactly at what point it ceases to be a heap? Exactly which grain changes it from heap to non-heap? This is called Sorites Paradox.

If a person starts plucking hair from his head, the person is not bald after plucking first hair, nor after plucking second hair. Then exactly when we are able to say that person is starting to get bald?


Aristotelian logic i.e the binary logic defines everything in TRUE or FALSE, BLACK or WHITE way. An element either belongs to the set A or it doesn't belong to set A, i.e A or not-A, it is able to not be both. A statement can only be true or false, there is nothing in between.

If we observe the world around us, there is vagueness, there is ambiguity. Things can not always be classified as Black or White but most of the times they have shades.Most of the times human beings think and communicate in gradation and not in crisp way. In our thought process or the natural languages, meaning of the words is often vague and even when it's well defined, while using the word as a label for a set, the boundaries inside which objects belong to or don't belong to a set are vague. A person X doesn't totally dislike strawberry ice cream, but is not very fond of it either, so she likes it to some degree. Some kids like school very a lot, some kids entirely dislike it, but there are a lot of kids who like some aspects of it and dislike some. Person with age 90 years, is old and person with age 20 years is young, but what about the person with age 35? Is he young or old?

Aristotelian logic falters in the scenario, when terms are not precisely defined. This is where Fuzzy Logic comes into picture.Fuzzy logic defines the terms in more-or-less way rather than yes-or-no way.

If we wish to define the set A of tall persons, then we would set a criterion to decide if a person is tall or not. Suppose we decide a person with height 5 feet 9 inches or more belongs to this set then a person with height 5 feet 8 inches doesn't belong to this set neither does person with height 4 feet 1 inch. So, both these folks belong to set not-A.

But does that mean the person having height 5 feet 9 inches is tall and person with height 5 feet 8 inch is not tall? rather than this crisp definition of sets, Fuzzy logic defines the concept of membership. Every element has a membership in the set, taking value between 0 and 1. The person having height 6 feet may have membership value 1, where as the person having height 5 feet 8 inches, may have 0.8 as membership value to this set and then on. So every element belongs to set A and set not-A as well, to some degree. each of cloth can not always be either dry or wet, it is able to be dry to some extent and wet to some extent, weather can be cold to some degree and hot to some degree.

In 1964, Professor Lotfi Zadeh developed the theory of Fuzzy sets. He was the first one to give this theory a definitive form, though a lot of thinkers in the past had pondered on this question of non-crisp sets. Buddha, founder of Buddhism, who lived in India around 500 BC, says that world is full of contradictions and almost everything contains some of its opposite, i.e things can be A or not-A at the same time. Bertrand Russell had encountered this theme of fuzziness when he stated his paradox.

Today, Fuzzy logic is used in a lot of day-to-day appliances, since it provides more human-like interpretation and reasoning in machines by regarding intermediate values between True/False, hot/cold, bright/dark, clean/dirty etc.

Fuzzy washing machines decide the washing cycle required to wash the laundry depending upon its degree of dirtiness. If it's 100% dirty, then say 2 minutes will be added to the basic washing cycle and 1 minute if it's 50% dirty and then on. it is able to also decide the amount of detergent to be added depending on the above degree of dirtiness of the laundry.

Smart Air-conditioners use fuzzy logic to adjust flow of air due to degree of hotness or coldness. Smart TVs adjust the colour and contrast modes. Japan is the leader when it comes to making use of Fuzzy Logic to make systems more intelligent.

In future, more and more systems can be built using Fuzzy Logic which incorporate human thinking, experience and reasoning rather than limiting it to only true/false values.