Anthony: It has been established that over 80 percent of those who use heroin have a history of having used marijuana  Such evidence would seem to prove that smoking marijuana definitely leads to heroin use  Judith: Maybe smoking marijuana does lead to heroin use, but it is absurd to think that citing those statistics proves that it does
After all, 100 percent of the people who take up heroin had a previous history of drinking water
demonstrating that Anthony's line of reasoning is flawed by showing that such reasoning can lead to clearly false conclusions