For many situations, we reason about a problem using information that is static.
During the course of solving the problem, the state (i.e., true or false) of the various facts remains constant. This type of reasoning is known as monotonic reasoning.
In some problems, the state of facts changes.
For example,
When the wind blows, the cradle will rock.
IF The wind blows.
THEN The cradle will rock.
Next, and with another borrow, consider what happens with our rule:
Auntie Em, it’s a twister! -> Wind blows -> Cradle rocks