Mr Rudd's Homework — Rules Run One Way

About this lesson

Two students, Wei and Dylan, both hear the same two rules about their teacher. Dylan uses the rules forwards and gets it right. Wei uses them backwards and gets it wrong. The important lesson here is that a conditional rule ("if A then B") only tells you what happens when A occurs — it never tells you that A is the only thing that can cause B. This mistake — reasoning backwards and assuming the cause — is one of the most common errors in OC TS.