Fuzzy Logic

There seem to be plenty of answers to the question of WHAT fuzzy logic

is, and HOW it works. There are several good primers that provide

a good introduction to those questions.

I want to know WHEN I should use it, and WHY. What will I gain from it?

Some say shorter and more simplified development time. But that is a

rather, um, vague answer.

There are many devices which [regretably?] can only be turned on or off.

Examples are an electric water heater, electric stove, and an air

conditioner. I do not understand how fuzzy logic can do anything but

complicate these matters.

One explanation was that if you set your AC on say, 75F, you don't want

the AC to oscillate on and off as the temp goes below and above that

point. But that's not how thermistats work anyway. Either they have

a trigger point and a setting for how long the AC stays on, or they

have two trigger points, one for turning it on, the other for turning

it off. Either way, you've basically defined "too cold" and "too hot".

Okay, so now we use fuzzy logic, and we start by defining how cold and

how hot each degree is. Then we fuzzify everything, apply rules, and

then defuzzify it. In the end, we still have one basic binary decision:

either