Contrapositives

A contrapositive is basically the equivalent to the original argument. The book uses "A" and "B" to explain this. "If A then B" and "If  not B then not A". It is a pretty concept overall and is something we run into all the time in our daily lives. Being able to identify the contrapositive sometime makes it easier to understand the original argument. It was kind of hard to grasps at first, but the example of getting a drivers licenses really cleared things up. That is, to be able to recieve a license, one must first pass the driving test. If you do not pass the driving test, then you do not have a license. As you can see, it is simply broken down using the "A" and "B". From this I was able to easily draw onto other examples such as "If the street light is green, you go" and "If you do not go then the light is not green".