Stephen Law

Many of us are familiar with the Post Hoc Ergo Propter Hoc Fallacy (' after this, therefore because of this) - Post Hoc Fallacy for short). It's the fallacy of supposing that, because B occurred after A, A must be the cause of B. For example: My car stopped working after I changed the oil, so changing the oil caused it to stop working. Or:  I wore my red jumper to the exam and I passed, so that jumper is lucky: it caused me to pass. This fallacy is so common, it gets a latin name. However, there's a related common fallacy that I think also deserves a name. I am going to call it the Non Post Hoc Fallacy (' not after of this, therefore not because of this), or, perhaps more memorably, the David Cameron Fallacy. Every now and then someone desperate to ‘prove’ that X is not causally responsible for Y – e.g poverty is not a cause of crime, will commit the following fallacy. They will argue that as X has often occurred without Y following, therefore X was not the