Editing Fuzzy logic (section)

==== IF-THEN rules ====
{{Main|Fuzzy rule}}
IF-THEN rules map input or computed truth values to desired output truth values. Example:
<syntaxhighlight lang="text">
IF temperature IS very cold THEN fan_speed is stopped
IF temperature IS cold THEN fan_speed is slow
IF temperature IS warm THEN fan_speed is moderate
IF temperature IS hot THEN fan_speed is high
</syntaxhighlight>

Given a certain temperature, the fuzzy variable ''hot'' has a certain truth value, which is copied to the ''high'' variable.

Should an output variable occur in several THEN parts, then the values from the respective IF parts are combined using the OR operator.